The profile of adverse events also was similar, although with a possible reduction in headache (6.4%–10.5% versus 12%–15% in the 11 pooled studies, and 15.8% in the long-term study) [9,23]. However, given the broad differences between the studies, direct comparisons should be interpreted with caution.
Two independent studies investigated once daily dosing with tadalafil. The first [18] tested once-a-day tadalafil 10 and 20mg as salvage cialis tadalafil 10mg tablets therapy for patients who were unresponsive to tadalafil 20mg on demand. Efficacy endpoints while on once-a-day therapy were all significantly higher than baseline and with endpoints achieved during on-demand dosing. The second [12] directly compared on-demand tadalafil 20mg with once-a-day tadalafil 10mg. The mean change from baseline was significantly higher for once-a-day (11.8 points) than for on-demand (8.7 points).
Based on these results, once-a-day dosing with tadalafil may provide superior efficacy compared with on-demand tadalafil. Also, 72% of patients preferred taking tadalafil once a day [12]. Because of the broad differences between the McMahon studies and the current study, direct comparisons were not made, but both studies show patients respond well to once-a-day tadalafil. Steady-state tadalafil plasma concentrations are attained within five days of once-a-day dosing, and exposure is approximately 1.6-fold greater than after a single dose [11]. Thus, after five days, a cumulative tadalafil plasma concentration equivalent to on-demand doses of 16 and 8mg would be achieved for the 10-mg and 5-mg doses, respectively. The McMahon once-a-day dosing studies reported two [18] and four [12] incidents of MI, all in patients with significant multiple vascular risk factors. All were determined to not be drug related [18].
| Product | Dosage | Quantity + Bonus | Price | |
|---|---|---|---|---|
| Cialis Generic | 40mg | 180 + 10 Pills | 277.29€ 264.09€ | |
| Cialis Generic | 60mg | 60 + 4 Pills | 145.06€ 138.15€ | |
| Cialis Generic | 60mg | 90 + 6 Pills | 196.67€ 187.30€ | |
| Cialis Generic | 40mg | 20 Pills | 59.47€ 56.64€ | |
| Cialis Generic | 10mg | 90 + 6 Pills | 146.17€ 139.21€ | |
| Cialis Super Active | 20mg | 90 + 10 Pills | 314.14€ 299.18€ | |
| Cialis Generic | 5mg | 20 Pills | 41.99€ 39.99€ | |
| Cialis Generic | 5mg | 30 + 4 Pills | 53.56€ 51.01€ | |
| Cialis Generic | 40mg | 120 + 8 Pills | 206.98€ 197.12€ | |
| Cialis Super Active | 20mg | 60 + 8 Pills | 230.32€ 219.35€ | |
| Cialis Professional | 20mg | 360 + 6 Pills | 807.03€ 768.60€ | |
| Cialis Original | 20mg | 64 + 4 Pills | 274.18€ 261.12€ |
The MI rates reported by McMahon are inconsistent with incidence rates of MI recorded in 35 clinical trials of tadalafil, which included four studies of daily dosing with tadalafil and 371 patient-years of exposure. The incidence rate of MI for these 35 studies was 0.33 per 100-patient years (n=10,460 patients, 5,088 patient-years exposure to tadalafil).
| Side Effect | Severity | Commonality | Recommendations |
|---|---|---|---|
| Headache | Mild | Very common | OTC pain relief, hydration |
| Flushing | Mild | Common | Cooling measures, reassurance |
| Nasal congestion | Mild | Common | Decongestants if needed |
| Muscle aches | Mild | Less common | Rest, hydration |
| Vision changes | Rare | Rare | Seek medical advice if occurs |
This rate is no higher than MI rates in placebo-treated patients (0.41 per 100 patient-years; n=2,118; 489 patient-years), or in an age-standardized male population (0.6 per 100 patient-years) [24].
However, since every-other-day dosing was efficacious, and nearly half the men preferred this regimen, every-other-day dosing with tadalafil may be another alternative regimen. In this study, both doses of tadalafil were well tolerated when taken daily. This is corroborated by both the high rate of treatment compliance and the low frequency of discontinuation caused by adverse events. The discontinuation rate in this study (3.4%) is numerically similar to that seen in on-demand studies (tadalafil 10/20mg; 1.6%–5.5%) [9,10,19–22] and in a long-term (18–24 months) study (tadalafil 5/10/20mg 6.3%) [23]. The incidence of adverse events in this study was similar to tadalafil cialis 5 mg that seen in the pooled analysis of 11 on-demand studies. Chronic dosing of PDE5 inhibitors may have medical benefits beyond ED. Chronic administration of PDE5 inhibitor therapy is efficacious in the treatment of pulmonary arterial hypertension [25] and may have cardioprotective effects for ischemia-reperfusion injury [26].
| Contraindication | Explanation | Recommended Action |
|---|---|---|
| Use with nitrates | Can cause dangerous blood pressure drop | Avoid concomitant use |
| Severe liver or kidney disease | Affects drug metabolism | Consult healthcare provider |
| Uncontrolled hypertension | Risk of adverse cardiovascular events | Medical supervision advised |
| Historical priapism | Risks of prolonged erections | Discuss with doctor |
A daily approach also may improve organic ED at the level of vascular endothelial function.
Recent data suggest both sildenafil and tadalafil could exert prolonged beneficial effects on vascular endothelial function if taken regularly [27–30].
| Benefit | Description | Evidence Level |
|---|---|---|
| Improved Erectile Function | Consistent daily use can help maintain erectile stability | Moderate |
| Increased Spontaneity | Reduced planning for medication enhances spontaneity | Moderate |
| Better Confidence | Steady performance may boost confidence | Anecdotal |
| Long-term Health Benefits | Possible cardiovascular benefits with regular use | Limited |
In this context, the FDA recently approved sildenafil citrate 20mg (Revatio®) at three times per day for the indication of primary pulmonary hypertension.
The most common treatment-emergent adverse events reported were dyspepsia, headache, back pain, upper abdominal pain, and myalgia (Table 3). One patient who took tadalafil 5mg reported an incident of “gritty feeling in the eyes.” There were no incidents of myocardial infarction (MI). ED is a chronic disease associated with underlying cardiovascular, neurological, endocrine, and psychological diseases and factors [17]. Historically, pharmacologic ED treatment has been linked to anticipated sexual activity. This required men to inject vasoactive drugs into the penis or apply mechanical devices such as a vacuum device just before sexual activity.
Oral PDE5 inhibitors alleviate many of these inconveniences and complications, but, treatment requires that dosing and sexual activity occur within a restricted time window. The current study suggests daily administration of tadalafil 5 and 10mg is efficacious and well tolerated in the treatment of ED. Patients who took tadalafil cialis without prescription in canada 5 and 10mg daily had significant EF improvement compared with placebo as assessed by IIEF, SEP, and GAQ. Although this study did not compare daily to on-demand dosing efficacy results are comparable to those seen in on-demand dosing studies. In the current study, the mean IIEF EF domain score increased by 9.7 (tadalafil 5mg) and 9.4 points (tadalafil 10mg). This suggests that daily use of PDE5 inhibitors may have further potential for non-ED and ED indications.
Tadalafil taken on demand is efficacious 30 minutes to 36hours after dosing [10]. In most cases, men are able to respond after the first dose, though for some men who need the greatest plasma levels of tadalafil, these would be achieved after the first few days of dosing. Further studies that address this point could be useful for clinicians. Recently, every-other-day dosing with tadalafil 20mg has been investigated [13] The efficacy results for every-other-day dosing are comparable with on-demand and once-a-day dosing, and 42% of men preferred every-other-day dosing. Although McMahon reported 72% of patients preferred daily dosing, once-a-day administration of 10mg (or 5mg) is scientifically difficult to compare with every-other-day administration of 20mg without a cross-over study. The interpretation of our results is subject to limitations.
Based on “yes” responses to GAQ, 84.5% (tadalafil 5mg) and 84.6% (tadalafil 10mg) of men thought treatment improved their erections (28.3% of men who took placebo, p<0.001). Of the men who had an IIEF EF domain score <26 at baseline, 51.5% (tadalafil 5mg) and 50.5% (tadalafil 10mg) achieved an EF domain score 26–30 (“no ED”) at endpoint (8.3% of men who took placebo, p<0.001). The safety evaluation included all 268 enrolled subjects. The mean number of doses per week was calculated as the number of doses taken divided by the number of weeks on therapy until the last scheduled visit. Subjects on tadalafil took an average of 6.5 doses per week; subjects on placebo took an average of 6.6 doses per week.
The majority (87.3%) of subjects completed the study. Nine (3.4%) discontinued because of adverse events (Fig. One patient in the tadalafil 5mg group with renal cell carcinoma died during the treatment period. The study investigator determined that his death was unrelated to the drug. Treatment-emergent adverse events were generally mild to moderate in severity: 53.8% reported as mild and 32.8% reported as moderate. First, patients with an IIEF EF domain score ≥26 were included in the primary analysis, which is consistent with clinical practice; most clinicians do not administer the IIEF. Exclusion of patients with “no ED” increased the magnitude of change from baseline but did not affect the statistical interpretation of the data.
Therefore, including these patients may be the more conservative analysis. Whether daily dosing with tadalafil could rescue nonresponders is unknown, because patients with prior experience with tadalafil and patients who were sildenafil nonresponders were not included in this study. Third, because this study did not compare once-a-day dosing with on-demand dosing or every-other-day dosing, we cannot adequately compare the efficacy and tolerability of the regimens or comment on which would be preferred, but the efficacy and tolerability of 5mg tadalafil taken daily appear to be comparable to the efficacy and tolerability of 20mg taken on demand or every other day.
Further studies that address this comparison could be useful for clinicians.
In conclusion, once-a-day dosing with tadalafil 5 and 10mg significantly improved EF versus placebo, and patients were highly compliant with this dosing regimen. Adverse events reported by patients tended to be mild or moderate in severity, and the rate of discontinuations caused by adverse events was similar to rates seen in studies that used on-demand dosing. Therefore, once-a-day dosing with tadalafil may be an attractive alternative to on-demand therapy for ED. These data have been reported previously in abstract form: Giuliano F, Porst H, Shen W, Chang S.
In an analysis of 11 pooled, placebo-controlled studies of tadalafil [9], the mean IIEF EF domain score increased by 6.5 (10mg) and 8.6 points (20mg). The magnitude of change in the mild subgroup in the current study was comparatively small, and frequently did not reach statistical significance. This is expected, since the baseline for mild patients is higher (less “room to improve”). However, the change was 4.5 (5mg) and 4.8 points (10mg), which is clinically significant (Raymond C. Rosen, Ph.D., personal communication).
Also, the sample size in this study limited the power of the analysis. When subgroups are larger, as in the 11 pooled studies (mild patients, n=112) a 3.7-point change (10mg on demand) reached statistical significance [9]. Because daily dosing with tadalafil was efficacious, this regimen may provide a novel approach to ED therapy in which sexual activity need not be tied to drug administration. As reported by Hanson-Divers et al., the five measures considered most important to patients in defining success were cure, pleasure, partner satisfaction, reproduction, and naturalness [8]. Thus, taking a long-acting drug once a day may be the best way for some patients to forget their ED and be ready for spontaneous sexual activity.