Sildenafil Citrate 2.5 mg/mL Oral Liquid

This is a critical abstract of a systematic

review that meets the criteria for inclusion on DARE.

What is sildenafil?

Maintenance of erection after penetration: 9/9 RCTs showed a statistically significant improvement with all doses of sildenafil compared to placebo. General efficacy question: 21/21 RCTs reported an improvement in erections with sildenafil treatment (65-82% improved) compared to placebo (18-26% improved). A dose-response relationship was seen over the dose range 25-100mg. Successful intercourse: Proportion of attempts at intercourse that were successful with sildenafil treatment increased compared to placebo treatment (6/9 RCTs list a positive outcome). One RCT found no increase in rates of attempted intercourse with sildenafil, despite increased success rates.

What should I tell my healthcare provider before taking sildenafil?

Erections hard enough for intercourse: In 6/6 RCTs a significant improvement in the number of grade 3 and 4 erections was seen with sildenafil treatment. Partner's questionnaire: Generally increasing partner satisfaction was seen with increasing sildenafil dose (10-100mg). Quality of life: Statistically significant but small quality of life treatment effects were seen in 4 RCTs. Adverse effects: Adverse events reported in >2% (range 2% - 10%) of patient treated (2RCTs) include headache, flushing, dyspepsia, nasal congestion, urinary tract infection, abnormal vision, diarrhoea, dizziness, rash, respiratory tract infection. No cases of priapism were sildenafil citrate chewable tablets reported in any of the sildenafil studies.

The International Index of Erectile Function

Cardiovascular: 18 RCTs give an overall incidence of cardiovascular events (other than flushing) of 3.0% with sildenafil and 3.5% with placebo. A comparable incidence rate was seen with sildenafil and placebo for serious cardiovascular events. No clinically significant changes in blood pressure, heart rate or ECG were seen with sildenafil treatment. Sildenafil had no direct effect on platelet aggregation. Death: 8/4500 patients treated with sildenafil in clinical trial died whilst taking the study drug or within 30 days of treatment. Each critical abstract contains a brief summary

• Take sildenafil on an empty stomach for faster absorption.
• High-fat meals may delay the effectiveness of the medication.
• Do not crush or chew sildenafil tablets; swallow whole.

of the review methods, results and conclusions followed

by a detailed critical assessment on the

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The authors state that if sildenafil were available for prescription in primary care the drug costs to an average health authority with a total population of 500,000 are estimated to be between 750,000 and 1,250,000 per annum, depending on the percentage of men who present for treatment. Burls A, Clark W, Gold L, Simpson S. Sildenafil: an oral drug for the treatment of male erectile dysfunction. Birmingham: University of Birmingham, Department of Public Health and Epidemiology. West Midlands Development and Evaluation Committee Report; 12. reliability of the review and the conclusions drawn.

• Sildenafil is sometimes used off-label for other medical conditions.
• Continuous use without medical supervision is not recommended.
• Follow your provider's instructions for frequency of use.

Implications of the review for

practice and research Sildenafil: an

What happens if I overdose?

The review did not specify which canada sildenafil outcomes included studies should measure. Phase II trials measured penile rigidity (using a Rigiscan) during visual or vibratory sexual stimulation. Phase III and some Phase II trials measured outcomes using the International Index of Erectile Function (IIEF): a self-administered questionnaire consisting of 15 questions around 5 domains of male sexual function: erectile function, orgasmic function, sexual desire, intercourse satisfaction, overall satisfaction. The authors do not state how many of the reviewers performed the selection. TTwo independent reviewers performed the validity assessment, but the method they used was not reported.

What is sildenafil used for?

The following aspects of validity were considered in the 'Results' section: blinding, control group, sample size, loss to follow-up. Two reviewers extracted data from all trials independently into pre-defined tables. Data were extracted on: source of information; cause of erectile dysfunction; number of patients; patient characteristics; treatments; duration; outcomes; p values; date of study. A narrative synthesis, with some pooling where mean scores (for response to questions) and mean proportions are presented. The methods used to combine data are not presented in the report.

Usual Pediatric Dose for:

No formal investigation of heterogeneity was carried out. Seven were Phase III trials and 14 were Phase II trials. Penile rigidity (Phase II trials only, n=7): In all studies an increased duration of rigidity >60% was seen with increasing doses of sildenafil. Frequency of penetration: 9/9 RCTs showed statistically significant improvements with all doses of sildenafil compared to placebo. Increasing improvement was apparent with increasing dose over the range 25-100mg. oral drug for the treatment

Overdose/Missed Dose

Six deaths were related to cardiovascular causes; in all cases it was plausible that the event was not related to the study drug. Diabetics: In general, smaller improvements were seen in diabetics than in those without diabetes. Spinal cord injury: sildenafil appears to show comparable efficacy in patients with erectile dysfunction solely attributable to spinal cord injury (but with intact spinal cord-mediated reflexes) to patients with erectile dysfunction of broad-spectrum aetiology. Radical prostatectomy: 4% of participants had erectile dysfunction as a result of radical prostatectomy. A subgroup analysis of the patients appeared ot show lower efficacy with sildenafil, with 40-50% achieving improved erections.

Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:

Age: Age did not affect response to sildenafil. A cost-utility analysis concluded that there is a great deal of uncertainty surrounding the assumptions used to calculate the cost/QALY of treating erectile dysfunction with sildenafil. The best estimate was approximately £7,000/QALY. Sensitivity analysis around the assumptions produced a range of cost/QALYs within the £3,000-£20,000/QALY "strongly supported" decision band used by the Development and Evaluation Committee. All trials showed a statistically significant improvement in erectile function in patients using sildenafil compared to placebo.

Diabetes-related impotence in the elderly

About 75-80% of men show a clinically significant improvement in erectile or sexual function on sildenafil compared to around 25% on placebo. The number needed to treat (NNT) was about 2. Many of the patients in the studies had some baseline erectile function and it is probable that in clinical practice, where the erectile function tends to be more impaired, the NNT may be higher. The drug has a relatively safe side-effect profile. The major contraindication is concurrent use of nitrates. of male erectile dysfunction - Databa...Sildenafil:

• Sildenafil should not be used with certain medications like alpha-blockers.
• Avoid alcohol consumption when taking sildenafil to reduce side effects.
• Discuss all medications with your doctor to prevent interactions.

an oral drug for the treatment of male erectile dysfunction

• Sildenafil's effects typically last for 4-6 hours.
• It does not increase sexual desire but enhances response.
• Onset of action can be affected by age and health status.

- Database of Abstracts of

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The research question sildenafil 60mg and inclusion criteria for the review were clear, however inclusion criteria for the primary studies were quite restrictive and possibly resulted in the population studied having more baseline erectile function than would be seen in clinical practice, which would limit the generalisability of the review findings. The authors state that validity assessment was undertaken but few details of this are presented in the report.The literature search was comprehensive and it is unlikely that any studies were missed. Some details of the review process are given but it is not stated how many reviewers screened studies for relevance. As all included phase III trials used the same outcome measures data could have been pooled using standard methods for meta-analysis and presented as forest plot and as relative risks and weighted mean differences with 95%CIs: this was not done and there is no description in the methods section of how the review authors synthesised data. The authors' conclusions do seem to follow from the results. Reviews of Effects (DARE): Quality-assessed Reviews

Before taking this medicine

^ "Viagra to be available without prescription in UK". A service of the National Library of Medicine, National Institutes of Health. Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-. To examine the effectiveness, safety and cost-effectiveness of sildenafil for the treatment of male erectile dysfunction.

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MEDLINE (1966 to June 1998), EMBASE (1988 to June 1998), Cochrane Library (Issue 3, 1998), PsycLIT (1996 to 1987 (sic)), National Research Register Interim version June 1998 and Pharm-line were all searched for articles containing the free-text terms "sildenafil" or "Viagra". The main Internet search engines were used using the terms "sildenafil" or "Viagra". The FDA centre for Drug Evaluation and Research, Joint Clinical Review for NDA-20-895 Viagra (Sildenafil), the BMJ, Lancet, JAMA, New England Journal of Medicine, BJGP, Drug, Inpharma and Scrip were all handsearched. Experts in the field and the manufacturers (Pfizer Ltd) were contacted. Reference lists of all relevant studies identified were scanned.

Specific interventions included in the review

The Science Citation Index was searched using all relevant studies identified. Both Phase II and Phase III studies were included. The authors planned to compare sildenafil to other current treatments for erectile dysfunction, but no evidence was found. The review did not specify inclusion criteria for participants, but all included studies recruited men aged 18 years and over with erectile dysfunction of at least 6 months duration, in a heterosexual relationship for at least 6 months: aetiology included diabetes and spinal cord injury. Men with the following disorders were excluded: anatomical deformities; other sexual disorders; elevated prolactin (3xULN) or low free testosterone (20% below LLN); major uncontrolled psychiatric disorders; history of alcohol or drug abuse; history of major haematological, renal or hepatic disorder; stroke or MI within 6 months; cardiac failure, unstable angina, ECG ischaemia or life threatening arrhythmia within 6 months; BP outside the range 90/50 to 170/100 mmHg; active peptic ulcer disease of bleeding disorder; clinically significant baseline laboratory abnormality; need for anticoagulants, nitrates, androgen or trazodone; need for aspirin or NSAIDs and history of peptic ulcer disease; unwillingness to cease using other therapy for erectile dysfunction; other experimental drug use within 3 months; history of retinitis pigmentosa.