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Efficacy of Continuous Dosing of Tadalafil Once Daily vs Tadalafil On Demand in Clinical Subgroups of Men With Erectile Dysfunction: A Descriptive Comparison Using the Integrated Tadalafil Databases

This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Associated Data

Abstract

Introduction

Various factors play a role in the development of erectile dysfunction (ED).

Aim

To provide a descriptive comparison of erectile function response for tadalafil on-demand (PRN) and once-daily (OAD) dosing regimens in patients with common comorbid conditions, treatments, or risk factors that can be considered when treating ED.

Methods

In total, 17 PRN and 4 OAD placebo-controlled studies were included in the integrated database in these pooled analyses. Data were analyzed from patients treated with placebo, tadalafil 10 mg (low dose), and 20 mg (high dose) for the PRN studies and placebo, tadalafil 2.5 mg (low dose), and 5 mg (high dose) for the OAD studies.

Main Outcome Measures

The effects of tadalafil were measured using the International Index of Erectile Function administered from baseline to week 12. A descriptive comparison of the efficacy of tadalafil PRN vs OAD was examined in the clinical populations.

Results

Baseline characteristics of 4,354 men were comparable between the PRN and OAD groups, with differences seen only in the variables of race, body mass index (BMI) of at least 30 kg/m 2 , and alcohol use. Tadalafil was efficacious at improving erectile function for all clinical populations, except for the low-dose OAD group, which demonstrated a weaker effect vs placebo than the high-dose OAD group, and the low- and high-dose PRN groups vs placebo for patients with BMI of at least 30 kg/m 2 for patients without a cardiovascular disorder, smokers, patients with ED duration shorter than 1 year, and patients without previous phosphodiesterase type 5 inhibitor use. Tadalafil was efficacious for patients with or without diabetes mellitus, arterial hypertension, hyperlipidemia, and alcohol use at baseline.

Conclusion

Tadalafil OAD and PRN regimens showed efficacy in patients with ED. No clinical populations of patients with ED seemed to benefit overwhelmingly from one dose regimen over the other.

Keywords: Erectile Dysfunction, Phosphodiesterase Type 5 Inhibitors, Tadalafil, Data Pooling, Treatment Efficacy

INTRODUCTION

Numerous factors such as age, weight, diabetes mellitus, cardiovascular disorders, smoking, arterial hypertension, and alcohol use can play a role in the development of erectile dysfunction (ED). 1–6 Owing to the various physical and psychosocial aspects of ED, 7 treatment of ED extends beyond improving erectile function (EF) response and satisfaction. 8–11

Phosphodiesterase type 5 (PDE5) inhibitors represent the first-line drug treatment for ED. 12,13 The PDE5 inhibitor tadalafil, with on-demand (PRN) 14–17 and once-daily (OAD) 18–22 dosing regimens, has demonstrated efficacy and safety in the treatment of ED. Psychosocial outcomes, spontaneity, and time concerns have shown significant improvement after treatment with long-acting compared with short-acting PDE5 inhibitors. 23,24 Treatment with tadalafil OAD has improved EF in patients with mild and mild to moderate impairments in EF after PRN PDE5 inhibitor therapy. 21,25 Other studies have shown that the OAD dosing regimen leads to high treatment satisfaction for the patient and his partner 19,25–27 and allows patients to have spontaneous sexual activity, thereby changing the requirement for dosing and sexual activity to be linked. An OAD dosing regimen also improves the patient’s ability to achieve and maintain erections and improves treatment satisfaction and psychosocial outcomes. 28 In addition, early initiation of the tadalafil OAD regimen protects against penile length loss after nerve-sparing radical prostatectomy. 29

Few clinical trials have compared the OAD and PRN regimens in the same study directly. Some researchers have reported the tadalafil OAD regimen is more efficacious in treating ED compared with the PRN dosing regimen, 30,31 whereas others have reported no significant differences between tadalafil OAD and PRN dosing regimens in improving erection and sexual satisfaction of patients with ED. 32 In 2014, Porst et al 33 reported on an integrated analysis of data from six placebo-controlled studies (OAD 2.5 or 5 mg) in patients with different ED characteristics and comorbidities and determined that treatment with the tadalafil OAD regimen resulted in clinically important improvements in patients with mild, moderate, or severe ED. In that study, there was an improvement in International Index of Erectile Function erectile function domain (IIEF-EF) scores in patients with arterial hypertension, cardiac disorder, or hyperlipidemia after treatment with tadalafil 2.5 or 5 mg; however, patients who were obese, smokers, and those with psychogenic ED reached a minimal clinically important difference (MCID; defined as mean improvement in IIEF-EF scores of at least four points 34 ) only after treatment with tadalafil 5 mg. Lewis et al 35 evaluated the efficacy of tadalafil in men with ED by demographic and ED characteristics and determined that the tadalafil PRN dosing regimen improved EF across a broad range of patients with ED, including patients with different comorbid conditions.

To our knowledge, there are no published integrated analyses that have looked at the efficacy of tadalafil PRN and OAD dosing regimens in the same context. Clinicians often seek prescribing information and guidance on the two regimens to provide the patient with information to assist in making appropriate treatment decisions.

AIM

In this article, we provide a descriptive comparison of EF and orgasmic function (OF) response to tadalafil PRN and OAD dosing regimens using the integrated tadalafil clinical trial databases. The purpose of this report is to offer this descriptive comparison of pooled data from tadalafil ED studies in patients with common comorbid conditions, treatments, or risk factors that might be considered when treating ED.

METHODS

Studies

In total, 17 PRN 14–17,36 and 4 OAD 19–21,37 placebo-controlled studies in men with ED were included in the integrated (March 2013) database that was used in these pooled analyses. Tadalafil studies in men with lower urinary tract symptoms associated with benign prostatic hyperplasia were excluded from these analyses owing to differences in the study population. Details about the general study design for these studies have been published. 14–17,19–21,36,37 For the 17 PRN studies that had identical study designs, data were analyzed from patients treated with placebo, tadalafil 10 mg (low dose), and tadalafil 20 mg (high dose). For the OAD studies, data were analyzed from patients treated with placebo, tadalafil 2.5 mg (low dose), and tadalafil 5 mg (high dose). The 5-mg PRN dose was not included in the analyses for this report because it is not a globally approved dose by regulatory authorities for the treatment of ED; therefore, for this report, the 10-mg PRN dose is considered low-dose PRN. Two studies were OAD registration studies that included men with ED, 19,20 and one study determined the impact of OAD treatment for men with ED on the sexual quality of life of their female partners. 21 One study evaluated OAD treatment in PDE5 inhibitor-naive men with ED. 37

Patient Population

Patients were men (≥18 years old) with at least a 3-month history of ED who remained sexually active with the same heterosexual partner. Some exclusion criteria included a history of certain cardiovascular diseases (eg, unstable angina, recent myocardial infarction, recent myocardial revascularization, and poorly controlled blood pressure), a history of radical prostatectomy with subsequent failure to achieve erections, and patients who had penile implants or deformities, clinically significant renal or hepatic insufficiency, and current treatment with nitrates, cancer chemotherapy, or antiandrogens. The details about the inclusion and exclusion criteria for some of these studies have been published. 14–17,19–21,36,37

Clinical Populations

Statistical Analyses

MAIN OUTCOME MEASURES

The effects of tadalafil on EF were measured with the IIEF, 39 which is a 15-item questionnaire that assesses domains of male sexual function that include EF, OF, sexual desire, intercourse satisfaction (IS), and overall satisfaction (OS). The IIEF was administered at baseline and at 4-week intervals during the treatment period (after baseline). In this study, patient scores were examined on the EF and OF domains of the IIEF. The EF domain score (sum of questions 1 [erection frequency], 2 [erection firmness], 3 [frequency of partner penetration], 4 [frequency of maintaining erection after penetration], 5 [ability to maintain erection to completion of intercourse], and 15 [confidence in achieving and maintaining erection]) ranges from 1 to 30. The OF domain score (sum of questions 9 [frequency of ejaculation] and 10 [feeling of orgasm and climax frequency]) ranges from 0 to 10. An increase in the EF or OF score indicates an improvement in these IIEF domains. Patient scores also were examined for SEP3 (successful completed intercourse attempts). In addition, patient scores were examined for the IIEF-IS domain (questions 6–8) and IIEF-OS domain (questions 13 and 14; supplement section).

RESULTS

Demographics and Baseline Characteristics

Table 1

Demographics and baseline characteristics *

Variable PRN OAD
Placebo (N = 1,002) Low dose (10 mg; N = 527) High dose (20 mg; N = 1,816) Total (N = 3,345) Placebo (N = 296) Low dose (2.5 mg; N = 96) High dose (5 mg; N = 617) Total (N = 1,009)
Age (y), mean (SD) 55.0 (11.2) 56.5 (11.5) 54.1 (11.4) 54.7 (11.4) 55.5 (11.2) 59.8 (11.5) 55.1 (10.8) 55.6 (11.1)
Age group, n (%)
320 (31.9) 149 (28.3) 625 (34.4) 1,094 (32.7) 86 (29.1) 22 (22.9) * 199 (32.3) 307 (30.4)
50–64 y 485 (48.4) 241 (45.7) 855 (47.1) 1,581 (47.3) 150 (50.7) 36 (37.5) * 309 (50.1) 495 (49.1)
≥65 y 197 (19.7) 137 (26.0) 335 (18.5) 669 (20.0) 60 (20.3) * 38 (39.6) * 109 (17.7) 207 (20.5)
Race, n (%)
White 473 (47.2) 235 (44.6) 979 (53.9) 1,687 (50.4) 256 (86.5) 80 (83.3) 515 (83.5) 851 (84.3)
Black 16 (1.6) * 3 (0.6) * 61 (3.4) * 80 (2.4) 6 (2.0) * 9 (9.4) * 12 (1.9) * 27 (2.7) *
Asian 443 (44.2) 274 (52.0) 603 (33.2) 1,320 (39.5) 1 (0.3) * 0 (0.0) * 3 (0.5) * 4 (0.4) *
Other 70 (7.0) 15 (2.8) * 173 (9.5) 258 (7.7) 33 (11.1) * 7 (7.3) * 87 (14.1) 127 (12.6)
BMI (kg/m 2 ), mean (SD) 26.7 (4.1) 26.6 (4.3) 26.9 (4.3) 26.8 (4.2) 28.2 (4.4) 28.5 (3.9) 28.2 (4.5) 28.2 (4.4)
BMI group, n (%)
817 (81.5) 439 (83.3) 1,451 (79.9) 2,707 (80.9) 214 (72.3) 73 (76.0) 447 (72.4) 734 (72.7)
≥30 kg/m 2 185 (18.5) 88 (16.7) 365 (20.1) 638 (19.1) 82 (27.7) 23 (24.0) * 170 (27.6) 275 (27.3)
Systolic BP (mmHg), mean (SD) 130.4 (14.5) 129.9 (14.6) 130.8 (15.0) 130.5 (14.8) 130.4 (13.8) 127.6 (13.3) 131.4 (13.9) 130.8 (13.9)
Diastolic BP (mmHg), mean (SD) 81.3 (8.5) 80.5 (8.6) 81.2 (8.3) 81.1 (8.4) 79.6 (9.1) 78.4 (8.6) 79.9 (9.0) 79.7 (9.0)
ED duration, n (%)
109 (10.9) 60 (11.4) * 248 (13.7) 417 (12.5) 36 (12.2) * 5 (5.2) * 72 (11.7) 113 (11.2)
≥1 y 893 (89.1) 467 (88.6) 1,568 (86.3) 2,928 (87.5) 260 (87.8) 91 (94.8) 545 (88.3) 896 (88.8)
IIEF-EF score, mean (SD) 14.4 (6.3) 14.2 (6.2) 14.6 (6.2) 14.5 (6.2) 14.6 (6.5) 13.1 (6.5) 14.9 (6.1) 14.6 (6.3)
IIEF severity, n (%)
Mild 380 (38.0) 202 (38.4) 721 (39.7) 1,303 (39.0) 119 (40.3) 33 (34.4) * 254 (41.6) 406 (40.6)
Moderate 284 (28.4) 147 (27.9) 515 (28.4) 946 (28.3) 82 (27.8) 24 (25.0) * 174 (28.5) 280 (28.0)
Severe 336 (33.6) 177 (33.7) 580 (31.9) 1,093 (32.7) 94 (31.9) 39 (40.6) * 182 (29.8) 315 (31.5)
Diabetes, n (%)
Yes 227 (22.7) 98 (18.6) 399 (22.0) 724 (21.6) 46 (15.5) * 17 (17.7) * 98 (15.9) 161 (16.0)
No 775 (77.3) 429 (81.4) 1,417 (78.0) 2,621 (78.4) 250 (84.5) 79 (82.3) 519 (84.1) 848 (84.0)
Hypertension, n (%)
Yes 274 (27.3) 138 (26.2) 506 (27.9) 918 (27.4) 110 (37.2) 39 (40.6) * 203 (32.9) 352 (34.9)
No 728 (72.7) 389 (73.8) 1,310 (72.1) 2,427 (72.6) 186 (62.8) 57 (59.4) * 414 (67.1) 657 (65.1)
Hyperlipidemia, n (%)
Yes 149 (14.9) 68 (12.9) 217 (11.9) 434 (13.0) 64 (21.6) 23 (24.0) * 111 (18.0) 198 (19.6)
No 853 (85.1) 459 (87.1) 1,599 (88.1) 2,911 (87.0) 232 (78.4) 73 (76.0) 506 (82.0) 811 (80.4)
Cardiovascular disorder, n (%)
Yes 358 (35.7) 187 (35.5) 638 (35.1) 1,183 (35.4) 135 (45.6) 48 (50.0) * 255 (41.3) 438 (43.4)
No 644 (64.3) 340 (64.5) 1,178 (64.9) 2,162 (64.6) 161 (54.4) 48 (50.0) * 362 (58.7) 571 (56.6)
Alcohol use, n (%)
Yes 554 (55.5) 312 (59.2) 953 (52.8) 1,819 (54.6) 144 (66.1) 68 (70.8) 238 (67.4) 450 (67.5)
No 444 (44.5) 215 (40.8) 851 (47.2) 1,510 (45.4) 74 (33.9) 28 (29.2) * 115 (32.6) 217 (32.5)
Smoking, n (%)
Yes 266 (26.7) 156 (29.6) 476 (26.3) 898 (26.9) 38 (19.5) * 12 (12.5) * 83 (28.2) 133 (22.7)
No 732 (73.3) 371 (70.4) 1,333 (73.7) 2,436 (73.1) 157 (80.5) 84 (87.5) 211 (71.8) 452 (77.3)
Previous PDE5 inhibitor, n (%)
Yes 441 (44.0) 165 (31.3) 977 (53.8) 1,583 (47.3) 148 (50.0) 86 (89.6) 300 (48.6) 534 (52.9)
No 561 (56.0) 362 (68.7) 839 (46.2) 1,762 (52.7) 148 (50.0) 10 (10.4) * 317 (51.4) 475 (47.1)
Any antihypertensive medication, n (%)
Yes 324 (32.3) 173 (32.8) 614 (33.8) 1,111 (33.2) 131 (44.3) 41 (42.7) * 248 (40.2) 420 (41.6)
No 678 (67.7) 354 (67.2) 1,202 (66.2) 2,234 (66.8) 165 (55.7) 55 (57.3) * 369 (59.8) 589 (58.4)
Antihypertensive medications, n (%)
0 678 (67.7) 354 (67.2) 1,202 (66.2) 2,234 (66.8) 165 (55.7) 55 (57.3) * 369 (59.8) 589 (58.4)
1 199 (19.9) 108 (20.5) 352 (19.4) 659 (19.7) 81 (27.4) 15 (15.6) * 126 (20.4) 222 (22.0)
>1 125 (12.5) 65 (12.3) 262 (14.4) 452 (13.5) 50 (16.9) * 26 (27.1) * 122 (19.8) 198 (19.6)

BMI = body mass index; BP = blood pressure; ED = erectile dysfunction; IIEF = International Index of Erectile Function; IIEF-EF = International Index of Erectile Function erectile function domain; N = number of randomized subjects; n = number of subjects with non-missing data; OAD = once a day; PDE5 = phosphodiesterase type 5 inhibitor; PRN = as needed.

Efficacy

IIEF-EF Domain

Treatment with tadalafil 5 mg (high dose) OAD and 10 mg (low dose) and 20 mg (high dose) PRN demonstrated significantly improved EF as measured by the placebo-adjusted IIEF-EF LS mean improvements ( Figure 1 ) for all variables examined. Tadalafil 2.5 mg (low dose) did not demonstrate significantly improved EF in several clinical populations ( Figure 1 ). In some clinical subgroups, there was insufficient powering owing to small numbers. The results were consistent across all doses and regimens, with few exceptions. There was a difference in response in the low-dose OAD regimen across different age groups, with a weaker effect seen for the low-dose OAD regimen for patients younger than 50 and at least 65 years old. There was a weaker effect seen in the low-dose OAD regimen for patients with BMI of at least 30 kg/m 2 , patients without a cardiovascular disorder, patients who smoked, patients with ED duration shorter than 1 year, and patients without previous PDE5 inhibitor use. Tadalafil was efficacious across all doses and regimens for patients with or without diabetes mellitus, hypertension, hyperlipidemia, and alcohol use at baseline. There was a numerical difference in response for low-dose OAD and PRN regimens compared with high-dose regimens in patients taking more than one antihypertensive agent.

Efficacy of tadalafil PRN vs OAD in various clinical populations as demonstrated by IIEF-EF: (A) age, (B) baseline BMI, (C) baseline diabetes, (D) cardiovascular disorder, (E) baseline hypertension, (F) hyperlipidemia, (G) smoking, (H) alcohol use, (I) previous PDE5 inhibitor use, (J) number of antihypertensive medications, (K) ED duration.The lower dose is 10 mg for PRN and 2.5 mg for OAD, and the higher dose is 20 mg for PRN and 5 mg for OAD.The numbers within the bars indicate the number of patients with non-missing data at baseline and at least one visit after baseline. The x indicates fewer than 64 patients in the subgroup. The dotted line represents the minimal clinically important difference of at least 4 change from baseline to end point (no clinically meaningful cutoff value has been defined for International Index of Erectile Function orgasmic function domain or other ED indicators; hence, dotted lines are not included in the other figures). The error bars represent 95% CIs. *P P P

The proportion of patients achieving MCID at end point in the IIEF-EF domain and the odds ratios of tadalafil low-dose (OAD 2.5 mg or PRN 10 mg) and high-dose (OAD 5 mg or PRN 20 mg) groups vs the respective placebo groups are presented in Table 2 . The odds ratios were significant for all clinical populations examined, and the results were fairly consistent across all doses and regimens, with the exception of the low-dose OAD regimen in the clinical populations at least 65 years old, with baseline BMI at least 30 kg/m 2 , and who smoked.

Table 2

Proportion of patients achieving minimal clinically important difference (change ≥ 4 from baseline to end point) at end point (week 12, last observation carried forward) in the international index of erectile function erectile function domain *

Variable PRN OAD
Low dose (10 mg; n = 527) High dose (20 mg; n = 1,816) Low dose (2.5 mg; n = 96) High dose (5 mg; n = 617)
N n OR (TAD vs PBO) N n OR (TAD vs PBO) N n OR (TADA vs PBO) N n OR (TAD vs PBO)
Age (y)
139 96 3.34 § 597 456 4.24 § 21 * 13 3.00 † 191 151 5.27 §
50–64 219 146 5.20 § 813 613 6.72 § 35 * 22 4.25 § 299 207 4.65 §
≥65 128 82 4.99 § 298 217 6.56 § 37 * 16 2.47 103 68 6.22 §
Baseline BMI (kg/m 2 )
408 279 4.68 § 1,368 1,027 5.70 § 71 42 3.84 § 427 314 5.64 §
≥30 78 45 3.47 § 341 260 5.73 § 22 * 9 1.37 166 112 3.62 §
Baseline diabetes
Yes 88 51 3.93 § 372 246 4.41 § 17 * 9 3.78 † 93 55 3.78 §
No 398 273 4.61 § 1,337 1,041 6.30 § 76 42 2.99 § 500 371 5.34 §
Baseline cardiovascular disorder
Yes 174 100 3.32 § 596 434 5.51 § 47 * 26 3.70 § 244 163 5.15 §
No 312 224 5.36 § 1,113 853 5.79 § 46 * 25 2.31 † 349 263 4.88 §
Baseline hypertension
Yes 127 68 2.80 § 477 345 5.35 § 38 * 18 2.84 † 193 126 4.90 §
No 359 256 5.36 § 1,232 942 5.87 § 55 * 33 3.04 § 400 300 5.00 §
Baseline hyperlipidemia
Yes 59 † 42 6.05 § 193 141 5.77 § 23 * 12 3.64 † 105 72 5.92 §
No 427 282 4.30 § 1,516 1,146 5.69 § 70 39 2.86 § 488 354 4.70 §
Smoking
Yes 144 100 4.32 § 455 346 4.94 § 11 * 5 1.04 81 58 2.44 †
No 342 224 4.50 § 1,247 937 6.02 § 82 46 3.50 § 210 148 5.57 §
Alcohol use
Yes 286 197 5.07 § 893 681 6.28 § 66 34 2.95 § 235 172 5.62 §
No 200 127 3.87 § 804 597 5.20 § 27 * 17 2.94 † 114 79 3.03 §

BMI = body mass index; N = number of subjects with baseline and end-point results; n = number of subjects achieving minimal clinically important difference at study end point; PBO = placebo; OAD = once a day; OR = odds ratio; PRN = as needed; TAD = tadalafil.

IIEF-OF Domain

Treatment with tadalafil low-dose and high-dose OAD and PRN regimens demonstrated significantly improved OF as measured by the placebo-adjusted IIEF-OF LS mean improvements ( Figure 2 ) for most clinical subpopulations examined (there is no clinically meaningful cutoff value that has been defined for IIEF-OF or the other ED indicators). The exceptions were with the low-dose OAD regimen in men younger than 50 years, obese men, those who smoked, those who did not have previous PDE5 inhibitor use, those treated with one antihypertensive medication, those with ED duration shorter than 1 year, and those with diabetes mellitus who did not show placebo-adjusted LS mean significant improvements with the low-dose and high-dose OAD regimens. All these groups had insufficient powering, with the exception of the high-dose OAD regimen in patients with diabetes mellitus. There was a difference in response in the low-dose OAD regimen across different age groups, with a greater effect seen for the low-dose OAD regimen in the 50- to 64-year-old group and for patients who had a cardiovascular disorder at baseline. There also was a difference in response in the high-dose OAD regimen across different groups, with a weaker effect seen for patients who had diabetes mellitus at baseline. Tadalafil was efficacious across all doses and regimens for patients with BMI less than 30 or at least 30 kg/m 2 and with or without hypertension, hyperlipidemia, smoking, and alcohol use at baseline.

Efficacy of tadalafil PRN vs OAD in various clinical populations as demonstrated by IIEF-OF: (A) age, (B) baseline BMI, (C) baseline diabetes, (D) cardiovascular disorder, (E) baseline hypertension, (F) hyperlipidemia, (G) smoking, (H) alcohol use, (I) previous PDE5 inhibitor use, (J) number of antihypertensive medications, (K) ED duration. The lower dose is 10 mg for PRN and 2.5 mg for OAD, and the higher dose is 20 mg for PRN and 5 mg for OAD. The numbers within the bars indicate the number of patients with non-missing data at baseline and at least one visit after baseline. The x indicates fewer than 64 patients in the subgroup. The error bars represent 95% CIs. *P < .05; **P < .01; ***P < .001. BMI = body mass index; ED = erectile dysfunction; IIEF-OF = International Index of Erectile Function orgasmic function domain; LS = least squares; OAD = once daily; PBO = placebo; PDE5 = phosphodiesterase type 5; PRN = on demand.

IIEF Satisfaction Domains

The satisfaction results, IIEF-IS (Supplementary Figure 1) and IIEF-OS (Supplemental Figure 2), showed a similar pattern to the IIEF-EF results. Tadalafil 2.5 mg (low dose) did not demonstrate significantly improved IS as measured by the placebo-adjusted IIEF-IS score in several clinical populations, including patients younger than 50 and at least 65 years old, patients with BMI of at least 30 kg/m 2 , smokers, patients with no alcohol use, those without previous use of PDE5 inhibitors, patients with diabetes, patients without a cardiovascular disorder, patients treated with one or more than one antihypertensive medication, patients with ED duration shorter than 1 year, and patients with hyperlipidemia. Tadalafil 2.5 mg (low dose) did not demonstrate significantly improved OS as measured by the placebo-adjusted IIEF-OS score in several clinical populations, including patients at least 65 years old, patients with BMI at least 30 kg/m 2 , smokers, patients with no alcohol use, patients without previous PDE5 inhibitor use, patients treated with one antihypertensive medication, patients with ED duration shorter than 1 year, and patients with diabetes, hypertension, or hyperlipidemia.

Sexual Encounter Profile, Question 3

Treatment with tadalafil low-dose and high-dose OAD or PRN regimens demonstrated significantly improved SEP3 as measured by the placebo-adjusted SEP3 LS mean improvements ( Figure 3 ) for all variables examined with the exception of low-dose OAD in patients who were at least 65 years old, obese patients, patients who smoked, those who were not treated previously with a PDE5 inhibitor, and patients who had ED duration shorter than 1 year (all these groups had insufficient powering).

Efficacy of tadalafil PRN vs OAD in various clinical populations as demonstrated by SEP3: (A) age, (B) baseline BMI, (C) baseline diabetes, (D) cardiovascular disorder, (E) baseline hypertension, (F) hyperlipidemia, (G) smoking, (H) alcohol use, (I) previous PDE5 inhibitor use, (J) number of antihypertensive medications, (K) ED duration. The lower dose is 10 mg for PRN and 2.5 mg for OAD, and the higher dose is 20 mg for PRN and 5 mg for OAD. The numbers within the bars indicate the number of patients with non-missing data at baseline and at least one visit after baseline. The x indicates fewer than 64 patients in the subgroup. The error bars represent 95% CIs. *P < .05; **P < .01; ***P < .001. BMI = body mass index; ED = erectile dysfunction; IIEF-IS = International Index of Erectile Function intercourse satisfaction domain; LS = least squares; OAD = once daily; PBO = placebo, PDE5 = phosphodiesterase type 5; PRN = on demand; SEP3 = Sexual Encounter Profile, question 3.

The proportion of patients achieving MCID at end point in SEP3 and the odds ratios of tadalafil low-dose (OAD 2.5 mg or PRN 10 mg) and high-dose (OAD 5 mg or PRN 20 mg) groups vs the respective placebo groups are presented in Supplementary Table 1. The odds ratios were significant for all clinical populations examined, including age, smoking, alcohol use, and baseline BMI, diabetes, cardiovascular disorder, hypertension, and hyperlipidemia, and the results were fairly consistent across all doses and regimens, with the exception of the low-dose OAD regimen in the clinical populations younger than 50 and at least 65 years old, with baseline BMI of at least 30 kg/m 2 , with diabetes mellitus, with no cardiovascular disorder, and those who smoked.

DISCUSSION

The results of these analyses of men with ED demonstrate that diabetes mellitus, arterial hypertension, hyperlipidemia, and alcohol use at baseline do not appear to have a major impact on the effect of tadalafil treatment on EF with either dose or regimen as measured by the mean change from baseline to end point in the IIEF-EF score in these clinical populations. For the group with baseline diabetes mellitus, there were small patient numbers for the low-dose OAD group; however, because patients with diabetes are usually more difficult to treat, the results suggest efficacy of low-dose OAD in this clinical subgroup. This confirmed the findings from previous studies that demonstrated that OAD and PRN dosing are efficacious across a broad spectrum of clinical subgroups. 33,35

The results were not comparable for the categories of baseline age: there was a weaker (worse) effect seen with the low-dose OAD regimen for patients younger than 50 and at least 65 years old vs placebo compared with the high-dose OAD regimen and low- and high-dose PRN regimens vs placebo. Although it is difficult to compare these groups because of various confounding factors, there might be a signal in patients at least 65 and younger than 50 years old indicating that the tadalafil low-dose OAD regimen might not be optimum for this subpopulation. However, because the patient numbers are small (smaller than the sample size requirement of 64 patients per group to achieve 80% power), it is important to interpret these results with caution. The results from the low-dose OAD regimen in patients who were not treated previously with a PDE5 inhibitor, patients with ED duration shorter than 1 year, and patients who are smokers also have small numbers, making their interpretation less robust. A smaller effect was seen in the low-dose OAD group for patients with BMI of at least 30 kg/m 2 ; however, given the relatively few patients in this category, strong statements cannot be made. This could be of interest for further investigation. The data showed a weaker effect for the low dose for the PRN and OAD regimens in patients with BMI of at least 30 kg/m 2 . The response in the low-dose group with BMI of at least 30 kg/m 2 is predictable compared with the group with BMI less than 30 kg/m 2 or compared with patients taking the higher dose, because a high BMI correlates with the presence of diabetes mellitus, arterial hypertension, hyperlipidemia, and other confounding factors linked to obesity, making this one of the more difficult-to-treat subpopulations. Studies have shown that in obese patients, EF improves after weight loss induced by bariatric surgery or lifestyle intervention. 40,41 There was a weaker effect seen in the low-dose OAD regimen for patients who did not have a cardiovascular disorder and for patients who smoked. Normal erection depends on penile vascular endothelial function, and smoking can have an adverse effect on vascular endothelium and lead to an increased risk for ED. 42–44 Therefore, the weaker effect seen in smokers in this study is not surprising; however, the numbers were small in this subpopulation of patients (

The results suggest low-dose OAD and PRN regimens can have a smaller effect than high-dose regimens in patients taking more than one antihypertensive agent, although this is not conclusive owing to the small patient numbers. Further investigation could be of interest in this clinical subgroup.

The SEP3 results followed a similar pattern to those of the IIEF-EF, in which treatment with tadalafil low-dose and high-dose OAD or PRN regimens demonstrated significant improvement in SEP3 for all variables examined except for low-dose OAD in some clinical populations.

Orgasmic function has not routinely been reported in PDE5 inhibitor studies. In this study, for patients with diabetes mellitus, there was a smaller effect on OF with the high-dose OAD regimen compared with the PRN regimen, suggesting that patients with diabetes mellitus might respond to PRN treatment more than to OAD treatment. This observation should be interpreted with caution, because the low-dose OAD arm was not sufficiently powered. There also was a noticeable difference in the placebo response arms between the different treatment regimens in the diabetes mellitus population.

The baseline characteristics were comparable between the PRN and OAD groups for the variables of age, blood pressure, ED duration, IIEF score, and IIEF severity. There was a difference in the percentage of patients by race between the PRN and OAD groups, with a larger percentage of white patients in the OAD group and a larger percentage of Asian patients in the PRN group. This difference in race reflects the differences in geographic locations where the trials were carried out. Most PRN studies were conducted in Asian countries such as Taiwan, Korea, India, mainland China, Philippines, Singapore, Hong Kong, Indonesia, and Malaysia, which resulted in the discrepancy of 39.5% vs 0.4% of patients being Asian in the PRN vs OAD groups. In addition, some OAD studies were conducted primarily in Europe and the United States, resulting in most men being white in the OAD studies. Studies have shown that ethnicity can be a contributing factor in how men experience patterns of recovery of sexual function after radical prostatectomy 45 and in how they perceive improvements in erection. 35 The differences in race and ethnicity between the OAD and PRN groups in these analyses need to be considered when results are interpreted. Other baseline characteristics that differed between the individual groups included BMI, with more patients classified as obese in the OAD group than in the PRN group, and alcohol use, with heavier use in the OAD group than in the PRN group. In addition, there was a larger percentage of patients who did not have diabetes mellitus in the OAD group than in the PRN group.

This study examined EF response in patients with ED and provided the first descriptive comparison of tadalafil OAD and PRN low-dose and high-dose regimens in multiple clinical populations. However, the study is limited by several variables. Because of the inclusion and exclusion criteria inherent to enrolling patients in clinical trials, patients in these analyses might not completely represent the general population. It is difficult to draw conclusions and make robust inferences for some subgroups with small patient numbers, particularly for those in the low-dose OAD group (a simple power calculation showed 64 patients per group were required to achieve 80% power assuming a 0.5 effect size). In addition, the difference in race in the clinical studies across the tadalafil regimens discussed can introduce bias. A direct comparison between the two regimens is not possible because the PRN and OAD regimens were not studied head-to-head in the same study. Moreover, indirect comparisons were not possible because the placebo treatments were not shared in all studies owing to differences in formulation and regimen. With many potential measured or unmeasured confounders, it is not practically feasible to use a model-based approach, adjusting for those confounding factors, to compare doses across regimens. With all these considerations, we resorted to a descriptive comparison between regimens.

In conclusion, tadalafil OAD and PRN regimens, at low and high doses, showed efficacy in patients with ED across the clinical subpopulations examined. We did not find clear evidence of clinical populations of patients with ED in which PRN performed meaningfully better than an OAD dosing regimen.

Cialis vs Cialis Daily: What’s the Difference?

Wouldn’t it be great if you didn’t have to take your ED med just before sex?

Cialis® Daily (tadalafil) is the only erectile dysfunction (ED) medication that’s intended to be taken once daily, every day, in order to prepare your body for intimacy at any time.

But it can be confusing understanding the differences in Cialis Daily dosage vs Cialis used on-demand. Let’s clear up the confusion.

Quick Facts About Cialis vs Cialis Daily

  • Cialis (tadalafil) is a PDE5 inhibitor like Viagra (sildenafil). They work by the same mechanism in the body and are the two most popular ED medications by volume in the U.S.
  • Cialis (tadalafil) comes in 5 mg, 10 mg, and 20 mg doses for on-demand use (just before sexual intimacy).
  • Cialis (tadalafil) also comes in 2.5 mg and 5 mg doses to be taken once daily (Cialis Daily) without worrying about timing sexual activity.
  • All doses of Cialis and generic tadalafil are available affordably and easily from Rex MD.

Which Cialis Dose is Best?

Cialis is the brand name for tadalafil, the third PDE5 inhibitor approved by the FDA after Viagra (sildenafil) and Levitra (vardenafil). All three are now available as generic drugs for cheaper than ever before, and they’re all effective for most men with ED.

Cialis is available in a wide variety of doses – and not all are to be used the same.

Cialis comes in 5 mg, 10 mg, and 20 mg doses for use directly before sexual intimacy. Eli Lilly reports that Cialis 20 mg has been shown to improve the ability of men with ED to have a single successful intercourse attempt for up to 36 hours after dosing. Cialis also comes in 2.5mg and 5mg doses to be taken once every day, essentially priming your system for sexual intimacy at any time. In these lower doses, it’s often called Cialis Daily.

Because of this, daily Cialis has become a popular option for men with ED who may have frequent sex or simply don’t want to worry about taking a medication before intimacy.

The FDA-approved Cialis prescribing label demonstrates these differences:

The History of Cialis

Cialis was first approved for the treatment of ED in 2003, five years after Viagra’s landmark approval in 1998 as the first medication for ED, and about two months after Levitra (vardenafil).

Five years later, in 2008, the FDA approved Cialis for daily use in new dose forms: 2.5 mg and 5 mg. According to Eli Lilly, the drugmaker behind Cialis, once-daily Cialis may be “most appropriate for men with ED who anticipate more frequent sexual activity (e.g. twice weekly).”

Cialis obtained “blockbuster status” in 2005 when it reached $1 billion USD in worldwide sales, and then went on to generate $2 billion in one year globally a few years later.

How Much Does Daily Cialis Cost?

Cialis, Cialis Daily, and tadalafil in all four doses are available affordably through Rex MD. We carry all major FDA-approved ED meds at industry-beating prices.

With Rex MD, you can get daily Cialis for as low as $3/dose, and our system is set up for simplicity: medications prescribed through our online visit process (if approved), delivered discreetly with 2-day free shipping, and refilled each month with no hassle.

How Does Cialis Daily Work?

Cialis and Cialis Daily are both tadalafil, one of the most effective and popular PDE5 inhibitors. That’s right – all of the medications approved by the FDA for the treatment of ED are PDE5 inhibitors, which stands for phosphodiesterase-5.

PDE5 is an enzyme that breaks down cGMP in the body. What does cGMP do?

CGMP is a substance that’s central to getting a firm erection. It promotes increased blood flow in the penis, leading to more blood (as much as 7x normal!) and swelling. As spongy tissues in the penis fill with blood, the dorsal vein at the top of your penis is compressed, helping to keep blood trapped in the penis. The blood continues to flow in and can’t escape – an erection forms.

PDE5 is the enzyme that breaks down and removes cGMP. It’s a natural enzyme that helps bring erections back to normal after intimacy. It’s a little like the brakes on a car. By stopping PDE5 from doing its usual thing – acting as a brake system – an erection can happen more easily.

That’s how all of the popular and effective ED meds work today.

Cialis and Cialis daily both do this, but Cialis Daily uses a lower dose to keep PDE5 reduced in the body at all times, rather than on-demand as with Cialis or Viagra.

Is Cialis Daily or Cialis Better?

Whether Cialis or Cialis Daily will be better for you is a personal question. Some guys like taking a medication daily so they’re ready for action. Others might prefer taking Cialis when they need it. And, Cialis is already known for how well it works over the course of a day or two compared to Viagra’s effects, which last only a few hours. (That’s why Cialis is often called the weekend pill – its effects can last 36 hours or longer.)

Curious if ED meds are right for you? Rex MD makes getting ED meds easier than ever, with online ordering and discreet, 2-day shipping if approved.

Cialis Daily vs Cialis

Cialis (Tadalafil) is a medication used to treat erectile dysfunction. It is classed as a PDE5 inhibitor, meaning that it relaxes the blood vessels to increase blood flow. As good blood flow is required to achieve an erection, Cialis enables people living with erectile dysfunction to obtain and sustain an erection, adequate for sexual penetration.

Order effective treatment for erectile dysfunction discretely

There are two types of Cialis available, Cialis Daily and standard Cialis. Cialis Daily is available in 2.5mg and 5mg doses and should be taken every day. This should allow you to obtain spontaneous erections as required. Alternatively, you can take Cialis, which is available in 10mg and 20mg doses. This would suit men who have less regular sex, or who have intermittent bouts of erectile dysfunction. It is recommended that first time users take a 10mg dose of Cialis or a 2.5mg dose of Cialis Daily. If you do not find these dosages effective, you may be able to increase your dosage to 5mg of Cialis Daily or 20mg of Cialis. If after changing your dosage, you still do not experience the desired effects, you could change to a different type of erectile dysfunction medication, such as Viagra, Levitra or Spedra. If you are unsure which brand to take, you could try an ED Trial Pack to find out which treatment suits you best.

Buy Viagra, Cialis or Spedra or their generic versions from Dr Felix, your trusted online pharmacy

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Efficacy of Continuous Dosing of Tadalafil Once Daily vs Tadalafil On Demand in Clinical Subgroups of Men With Erectile Dysfunction: A Descriptive Comparison Using the Integrated Tadalafil Databases

Introduction: Various factors play a role in the development of erectile dysfunction (ED).

Aim: To provide a descriptive comparison of erectile function response for tadalafil on-demand (PRN) and once-daily (OAD) dosing regimens in patients with common comorbid conditions, treatments, or risk factors that can be considered when treating ED.

Methods: In total, 17 PRN and 4 OAD placebo-controlled studies were included in the integrated database in these pooled analyses. Data were analyzed from patients treated with placebo, tadalafil 10 mg (low dose), and 20 mg (high dose) for the PRN studies and placebo, tadalafil 2.5 mg (low dose), and 5 mg (high dose) for the OAD studies.

Main outcome measures: The effects of tadalafil were measured using the International Index of Erectile Function administered from baseline to week 12. A descriptive comparison of the efficacy of tadalafil PRN vs OAD was examined in the clinical populations.

Results: Baseline characteristics of 4,354 men were comparable between the PRN and OAD groups, with differences seen only in the variables of race, body mass index (BMI) of at least 30 kg/m(2), and alcohol use. Tadalafil was efficacious at improving erectile function for all clinical populations, except for the low-dose OAD group, which demonstrated a weaker effect vs placebo than the high-dose OAD group, and the low- and high-dose PRN groups vs placebo for patients with BMI of at least 30 kg/m(2) for patients without a cardiovascular disorder, smokers, patients with ED duration shorter than 1 year, and patients without previous phosphodiesterase type 5 inhibitor use. Tadalafil was efficacious for patients with or without diabetes mellitus, arterial hypertension, hyperlipidemia, and alcohol use at baseline.

Conclusion: Tadalafil OAD and PRN regimens showed efficacy in patients with ED. No clinical populations of patients with ED seemed to benefit overwhelmingly from one dose regimen over the other.

Keywords: Data Pooling; Erectile Dysfunction; Phosphodiesterase Type 5 Inhibitors; Tadalafil; Treatment Efficacy.

Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Tips to Get the Most Out of Tadalafil (Cialis)

Cialis is a brand of tadalafil, one of the most popular medications to treat erectile dysfunction (ED). It was first approved in 2003.

Cialis is popular because it offers dosing flexibility, works well, and is convenient to take.

Let’s take a quick look at how Cialis works, then get into how long it takes to act, how long it lasts, and things you can do that affect results.

Taking the medication properly will help you get the maximum effect.

How common is ED?

ED is a common condition. It affects between 5 and 20 percent of men globally.

While there are many causes of ED, studies show the risk of ED increases with certain health issues, including:

Certain surgeries, such as prostate gland removal (radical prostatectomy) or surgeries in the lower pelvic or rectal area, may also cause ED.

Cialis is a phosphodiesterase type 5 (PDE5) inhibitor. It works for ED by relaxing smooth muscle in the blood vessels of the penis, therefore increasing blood flow.

PDE5 inhibitors only work in the presence of nitric oxide, which is naturally released during sexual arousal. PDE5 inhibitor medications work in 60 to 70 percent of people with ED.

Tadalafil is available in several doses in tablet form: 2.5 milligrams (mg), 5 mg, 10 mg, and 20 mg. Depending on the dose for ED, you can use it as needed before sexual activity, or take it once a day.

Let’s look at those two options, since dosing has a big effect on how it works.

Cialis offers two dosing options, which increase flexibility and allows greater choice. Your health, lifestyle, and the dosing of Cialis can affect how well the medication works.

A 2017 review of 16 studies comparing sildenafil (Viagra) and tadalafil found they’re equally effective for ED and have similar safety profiles.

But the review found tadalafil is preferred over sildenafil by users and their partners, and increases confidence.

Two important benefits of Cialis include dosing flexibility and long half-life. Tadalafil is the longest lasting PDE5 inhibitor medication for ED.

As-needed dosing

The usual starting dose for as-needed Cialis is 10 mg. It’s adjusted upward or downward depending on how you react to the medication.

Don’t take more than one dose per day to avoid the risk of a prolonged, painful erection (priapism), drop in blood pressure, or other serious side effects.

Take one tablet 30 minutes before sexual activity as directed by your doctor.

Daily dosing

The usual starting dose for once-daily Cialis is 2.5 mg. Your doctor might increase the dose to 5 mg based on how you react to the medication.

Take one tablet as prescribed at the same time each day. Many people who take Cialis prefer this dosing because it provides flexibility for timing of sexual activity.

For the as-needed dose, plan to take Cialis at least 30 minutes before sexual activity, but bear in mind it may take as long as 2 hours to take effect.

Also, Cialis requires sexual stimulation to be effective, so arousal is an important part of the equation.

There are many considerations that affect how long it takes Cialis to take effect for ED. This includes factors such as:

Tip for use

Take the daily dose at the same time every day to ensure there’s a steady level of the medication in your system.

Since you don’t need to plan ahead for sexual activity, many men and their partners prefer this dosing regimen.

Cialis can last from 24 to 36 hours. In some cases, it can last as long as 72 hours.

This is one of the reasons Cialis has high patient satisfaction ratings in surveys compared to other PDE5 inhibitors: It allows more spontaneous sexual activity.

How long the medication lasts depends on:

  • the dose
  • what kind of dose (as needed versus daily)
  • your age
  • your liver and kidney function
  • other medications you may be taking
  • your health condition
  • your lifestyle and diet

Take as directed

For as-needed dosing, take Cialis at least 30 minutes or more before sexual activity.

If your prescription involves taking Cialis daily, take it at the same time each day. This maintains steady levels of Cialis in your body.

Take as part of a lifestyle with physical activity

Smoking, heavy drinking, unmanaged stress, and an unhealthy diet can affect ED as well as how Cialis works, potentially leading to more side effects.

A healthy diet, increasing physical activity, and quitting smoking are important for wellness, physical health, and can affect the severity of ED.

Strategies to reduce stress and support your relationship with your partner can also improve sexual performance and well-being.

Communicate and stay relaxed

Working with a psychiatrist, therapist, or sex therapist can help you navigate strategies for the mental and emotional side of intimacy.

Other ways to improve your sexual performance include managing stress, working through relationship concerns, and treating performance anxiety.

If you’re anxious, stressed, depressed, or nervous, Cialis may not work as well. It’s important to relax and be aroused for the medication to work best.

High fat foods

Avoid high fat foods or heavy meals before taking Cialis and before sexual activity. High fat foods can affect how well Cialis works. It may also take longer to work.

Nitrates and other medications

Some medications can interact with Cialis and change its effectiveness. They include:

Be sure to talk to your doctor or pharmacist about how to take all your medications to avoid interactions.

It’s important to avoid Cialis if you take chest pain (angina) and blood pressure medications in the nitrate category or alpha blocker drugs. They can lower your blood pressure to dangerous levels.

Alcoholic beverages

Use caution with alcohol consumption when taking Cialis. Too much alcohol can affect your ability to become aroused. It can also cause excessive low blood pressure, leading to headache, dizziness, and fainting.

Grapefruit and grapefruit juice

Avoid grapefruit with Cialis. It can increase the levels of the medication in the blood, causing increased side effects.

Age

In some people over 65 years old, Cialis may last longer because it takes more time for your body to process the medication. This affects how soon it leaves your body.

Poor kidney function can increase Cialis levels in your body, increasing side effects. Your doctor may adjust your dose in this case.

Heart and other conditions

If you’re over 65, have a heart condition, or liver- or kidney-related problems, your doctor may need to adjust your dose of Cialis and monitor how the medication works for you.

Fake Cialis

Avoid buying Cialis without a doctor’s prescription. PDE5 medications are some of the most common counterfeit medications sold online. They can cause serious health risks.

Take as prescribed

Take Cialis exactly as prescribed by your doctor. Don’t take extra doses or change your dosing schedule without talking with your doctor to avoid side effects.

Common side effects

Serious side effects

Serious side effects of Cialis include:

  • priapism, a painful erection lasting longer than 4 hours, which can cause tissue damage
  • low blood pressure
  • changes in hearing and vision

When to get medical help

For more information on drug interactions or side effects of Cialis, talk to your doctor or pharmacist.

If you experience serious side effects, call 911 or your local emergency services.

ED is a common condition and can have many causes, including psychological and physiological reasons.

Risks of ED are higher with certain health conditions, so it’s important to openly talk with your doctor about your concerns. They can help you find the best treatment specific to your situation. This may include the need for ED medications.

Cialis is one of the most popular medications available for ED because it provides two types of dosing and lasts longer than other PDE5 inhibitor medications in this class, like sildenafil (Viagra).

There are several PDE5 inhibitor medications available, so discuss your needs and preferences with your doctor to select the medication best suited to you.

Remember, there are many causes for ED and many treatment options, including Cialis. Don’t be discouraged if Cialis doesn’t work the first time you try it. Your doctor can help adjust the dose or help you find other options to consider.

Last medically reviewed on August 27, 2020