We did not restrict our search to articles published in English and the following search terms were used in conjunction with: dapoxetine, SSRIs and premature ejaculation, sexual dysfunction.
We also searched the relevant references of all studies included in the analysis.
In summary, our meta-analysis has shown that either 30 mg or 60 mg dapoxetine on-demand orally was associated with a significantly greater increase in mean IELT and PGIC compared placebo. Additionally, 60 mg had a better efficacy than 30 mg dapoxetine on-demand orally. However, the meta-analysis also demonstrated that those treated with dapoxetine (especially 60 mg on-demand orally) reported more AEs than placebo or the dapoxetine 30 mg group. Nonetheless, the most commonly reported AEs were mild and tolerated. We searched the following databases up to and including June 2014: MEDLINE by PubMed, EMBASE, Cochrane Central Register of Controlled Trials (Cochrane Library). All retrieval literatures were independently performed by Cao D and HY.
| Product | Dosage | Quantity + Bonus | Price | |
|---|---|---|---|---|
| Tadalista Super Active | 20mg | 10 Pills | 55.64€ 52.99€ | |
| Priligy Generic Dapoxetine | 60mg | 20 + 4 Pills | 77.31€ 73.63€ | |
| Priligy Generic Dapoxetine | 60mg | 10 Pills | 47.63€ 45.36€ | |
| Kamagra Oral Jelly | 100mg | 21 Sachets | 95.92€ 91.35€ | |
| Priligy Generic Dapoxetine | 60mg | 90 + 10 Pills | 265.64€ 252.99€ | |
| Priligy Generic Dapoxetine | 60mg | 60 + 8 Pills | 183.06€ 174.34€ | |
| Levitra Professional | 20mg | 30 Pills | 119.12€ 113.45€ | |
| Priligy Generic Dapoxetine | 60mg | 30 + 6 Pills | 106.65€ 101.57€ | |
| Viagra Generic | 25mg | 90 + 6 Pills | 105.03€ 100.03€ | |
| Kamagra Gold | 100 mg | 180 + 6 Pills | 436.79€ 415.99€ | |
| Priligy Generic Dapoxetine | 60mg | 180 + 10 Pills | 494.76€ 471.20€ | |
| Viagra Generic | 150mg | 20 Pills | 55.02€ 52.40€ | |
| Priligy Generic Dapoxetine | 60mg | 120 + 10 Pills | 341.26€ 325.01€ |
Included in the study were all published or unpublished RCTs evaluating dapoxetine interventions for PE.
In addition, our meta-analysis comparing dapoxetine 60 mg with 30 mg on-demand orally proved that there was a statistically significant difference in IELT between the both groups; thus, 60 mg dapoxetine had dapoxetine 5mg a longer IELT than 30 mg on-demand for PE. The present findings are in agreement with the results of previous clinical trials that have reported significant improvement in the IELT with the use of dapoxetine9,10,11,12,13,14,15,16,17,18,19,20,21. Mean IELT was also significantly increased in all the studies not included in this meta-analysis. Mirone et al22 performed non-RCT trials in 2014 that compared dapoxetine 30–60 mg with alternative care/nondapoxetine, the results revealed that dapoxetine for treatment of PE had a longer mean IELT. The integrated analysis from five trials by McMahon et al19 also showed dapoxetine 30 and 60 mg on-demand significantly increased mean IELT compared with placebo (1.9 minutes for placebo, 3.1 and 3.6 minutes for dapoxetine 30 mg and 60 mg, respectively).
Our statistical results and subgroup analysis of PGIC demonstrated that dapoxetine was associated with a major improvement in PGIC. As shown in Figure 5, the overall RR was 2.14 (95% CI = 1.90–2.24) between dapoxetine and placebo, 2.01(95% CI = 1.69–2.38) between the dapoxetine 30 mg subgroup and placebo and 2.26 (95% CI = 1.91–2.67) between the dapoxetine 60 mg subgroup and placebo, respectively. Additionally, the present meta-analysis also demonstrated significant improvement in PGIC with 60 mg over 30 mg dapoxetine on-demand alone. Pryor et al9 thought that the PGIC condition as a study endpoint is informative with respect to men's perception to minor detectable changes in IELT. In other words, there is a positive relationship between the participants' PGIC ratings and mean change in IELT values.
The present findings agree with the results of previous clinical trials that reported a similar improvement in PGIC with dapoxetine versus placebo or comparing 60 mg versus 30 mg dapoxetine9,10,11,12,13,16,17,18,19,20,21. This analysis revealed the incidence of total AEs was more frequent with dapoxetine than with placebo and more common with dapoxetine 60 mg than 30 mg. However, from a review of all the studies reported in the literature, AEs of dapoxetine are generally tolerable. In the integrated analysis of the McMahon et al16 study, total AEs occurred in 35.1%, 47.0%, 60.3% subjects with placebo, dapoxetine 30 mg and dapoxetine 60 mg on-demand orally, respectively. In Figure 7, the total number of AEs occurred in 49.1% (2601/5293) and 20.7% (1040/5017) of subjects treated with dapoxetine and placebo, respectively. Studies comparing dapoxetine intervention versus placebo or another drug intervention were eligible for this review.
| Country | Approval Status | Notes |
|---|---|---|
| USA | Approved by FDA for PE | Prescription required |
| European Union | Approved in several countries | Prescription essential |
| Australia | Approved for PE | Sold under brand names |
| India | Available OTC in some pharmacies | Consult healthcare provider before use |
| Canada | Approved with prescription | Used for PE treatment |
All relevant studies were included in this study if they met the following criteria: (1) all patients were older than 18 years; (2) patients were diagnosed with
PE; (3) patients were treated with oral dapoxetine on-demand (1–3 hours before sexual activity); (4) data were available for at least one of the predefined outcome measurements.
We believe this heterogeneity might have resulted in the evaluation of the PGIC value using a 7-point scale (from −3 = much worse to 3 = much better) and AEs that were assessed using a subjective evaluation by individual patients. Additional factors might have been potentially amplified heterogeneity; these include differences in treatment duration, individual differences and mental or physical conditions. Secondly, some of the included studies did not report the outcome measures; hence, the statistical results might be influenced by the statistical parameters used for calculations. Additionally, nearly all sildenafil dapoxetine tablets trials included in this study lacked a clear description of the allocation concealment, but all trials included in this meta-analysis were RCTs, the methods were designed well. Thus, the data from the studies included in our meta-analysis were reliable. Studies were excluded if (1) patients were diagnosed with mixed sexual dysfunction such as erectile dysfunction plus PE; (2) patients were treated with a fixed-dose orally daily; (3) the data referred to data from an animal study; or (4) studies reported data from non-RCTs or quasi-RCTs. The following variables from each study were recorded independently by two reviewers and cross-checked: first author name, publication year, research design type, total number of patients enrolled, patient age, intervention method, outcome measures.
In Figure 8, the total number of AEs occurring with dapoxetine 60 mg or 30 mg were 58.2% (1421/2441) and 36.6% (907/2476), respectively. The most frequently reported AEs were nausea, dizziness, headache, diarrhea and insomnia22,23. Fortunately, the most common AEs with dapoxetine were mild or moderate in nature and were transient symptoms9,10,11,12,13,15,16,17,18,19,20,21,24,25. The present findings agree with the results of previous clinical trials that reported similar low incidence rates of side effects. Dapoxetine is a short-acting SSRI and doses of 30 mg and 60 mg have been evaluated through our meta-analysis.
Peak plasma concentrations of dapoxetine were observed within 1.01–1.27 hours after oral administration24. The elimination half-life time is 1.3–1.4 hours and there appears to be very little accumulation24. Dapoxetine undergoes rapid absorption, elimination and dose-dependent pharmacokinetics, which are unaffected by multiple dosing. The unique pharmacokinetic characteristics might be the reason why dapoxetine is the on-demand treatment of choice for PE. Safety and efficacy data have demonstrated that dapoxetine use produces acceptable improvement in the IELT and PGIC with on-demand use.
Thus, we also believe it is probably better suited as an on-demand treatment option for PE26. Our systematic review and meta-analysis has many drawbacks, the primary one being that this was a heterogeneous trial. In an attempt to reduce the high heterogeneity, we carried out a subgroup analysis among studies involving the drug dosage used (30 mg versus 60 mg groups). The heterogeneity was significantly decreased when comparing dapoxetine with placebo in the IELT by subgroup analysis. However, this heterogeneity of data still exists in the PGIC and AEs analyses, which we were unable to improve. In addition, the following primary outcome was extracted: IELT, defined as the time from the start of vaginal insertion to the start of intravaginal ejaculation and measured using the stopwatch.
The subgroup analysis indicated a statistically significant difference between treatment, with regards to 30 mg or 60 mg dapoxetine versus the placebo group in number of AEs reported (RR = 1.91, 95% CI = 1.36–2.70, P = 0.0002; and RR = 2.52, 95% CI = 1.58–4.02, P = 0.0001, respectively; Figure 7). Furthermore, AEs were assessed in six studies9,11,12,13,14,15 comparing two dapoxetine dosages (60 mg vs. 30 mg). This present plot demonstrated that a statistically significant difference existed between the 60 mg and 30 mg group in terms of the incidence of AEs (RR = 1.57; 95% CI = 1.31–1.89; P < 0.00001; Figure 8). Dapoxetine hydrochloride was the first drug originally approved for the on-demand treatment of patients with PE in 2008.
Since then, it has received marketing authorization in 59 countries worldwide7,8. In 2011, McMahon et al.16 published an integrated analysis of results from five phase 3 trials attempting to explore the efficacy and safety of dapoxetine for treatment of PE and they proposed that dapoxetine significantly improved all aspects of PE and was generally well tolerated. In 2012, McCarty et al17 published a systematic descriptive review and analyzed whether dapoxetine could be considered an efficacious and tolerable treatment for PE. However, no valid conclusions from these studies comparing 60 mg versus 30 mg dapoxetine could be obtained since these lacked strong statistical evidence. In this meta-analysis, in order to obtain a reliable and scientifically sound comparison of dapoxetine (30 and 60 mg) versus placebo and dapoxetine 60 mg versus dapoxetine 30 mg as on-demand oral treatment for PE, a precise search strategy was performed to include all relevant RCTs.
Therefore, studies of patients with erectile dysfunction18, non-RCTs19 and studies including patients with chronic, daily oral treatment with dapoxetine20,21 were excluded from the analysis of patients with PE. Ultimately, seven RCTs met the inclusion criteria for the present meta-analysis. To our knowledge, this is the most recent systematic review and meta-analysis comparing oral dapoxetine on-demand with placebo and comparing dapoxetine dosages (60 mg versus 30 mg) for the treatment of patients with PE. The present meta-analysis for IELT demonstrated that on-demand oral treatment with dapoxetine had an advantage over placebo despite the different dosages (30 mg and 60 mg) used. It demonstrated that on-demand oral dapoxetine was an effective treatment for PE.