17 PATIENT COUNSELING INFORMATION
White, Mobile, Ala.; J. Young, Laguna Hills, Calif.; and N. Zinner, Torrance, Calif. Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. Sex-ual behavior in the human male. Efficacy and safety of intracavernosal alprostadil in men with erectile dysfunction. Treatment of men with erectile dysfunction with transurethral alprostadil. Clinical Guidelines Panel on Erectile Dysfunction: summary report on the treatment of organic erectile dysfunction.
| Parameter | Value | Description |
|---|---|---|
| Half-life | 4 hours | Time to reduce plasma concentration by half |
| Maximum plasma concentration | 0.8-1.5 hours | Peak effect timing |
| Absorption rate | Rapid, within 30-60 minutes | After oral administration |
Nitric oxide as a mediator of relaxation of the corpus cavernosum in response to nonadrenergic, noncholinergic neurotransmission.
6.2 Post-marketing Experience
; T. Garland, Lawrence, N.J.; M. Gittelman, North Miami, Fla.; D. Gleason, Tucson, Ariz.; F. Govier, Seattle; L.
Other Medical Problems
Hoffman, Gurnee, Ill.; J.M. Kaufman, Aurora, Colo.; I. Klimberg, Ocala, Fla.; V. Longo, New London, Conn.; T. Malloy, Philadelphia; A. N Engl J Med 1992;326:90-94 Andersson, K-E, Wagner, G. Physiology of penile erection. The role of nitric oxide in the physiology of erection. Sildenafil: an orally active type 5 cyclic GMP-specific phosphodiesterase inhibitor for the treatment of penile erectile dysfunction. Sildenafil, a novel effective oral therapy for male erectile dysfunction.
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Br J Urol 1996;78:257-261 Rosen, RC, Riley, A, Wagner, G, Osterloh, IH, Kirkpatrick, J, Mishra, A.
What to avoid
In the dose-escalation study, 9 men (6 percent) stopped taking sildenafil and 13 men (8 percent) stopped taking placebo. One man stopped taking sildenafil because of treatment-related headache and flushing, and one man stopped because of an insufficient response. Laboratory-test results indicated no evidence of sildenafil-induced abnormalities. The most frequently reported adverse effects of sildenafil in the two studies were transient headache, flushing, dyspepsia, and rhinitis (Table 3). Transient visual disturbances (i.e., changes in the perception of color hue or brightness) were reported by some men.
Less common
The frequency of these adverse effects increased with increasing doses of sildenafil, but the symptoms were usually mild and lasted a few minutes to a few hours after dosing. No man reported priapism during the studies. Of the 225 men enrolled in the open-label extension study, 207 (92 percent) completed an additional 32 weeks of sildenafil treatment. Four men (2 percent) withdrew because of treatment-related adverse effects (headache in two, intermittent flushing and blurred vision in one, and groin pain and headache in one). We found that sildenafil improves sexual function in men with erectile dysfunction.
Prior authorization
In keeping with sildenafil's mode of action (i.e., the drug causes erection only in response to sexual stimulation), the studies were performed entirely in a natural environment, which meant that we had to rely on the men's own reports of efficacy. However, the self-administered International Index of Erectile Function has a high degree of sensitivity and specificity for detecting treatment-related changes in men with erectile dysfunction.13 This questionnaire, together with the global-efficacy question, provided a comprehensive assessment of erectile function during a specified recall period (four weeks), and the event log provided information about individual events during treatment. The men's partners were questioned in each of the studies, and although the results corroborated the men's efficacy assessments, only 25 percent of the partners completed the optional questionnaire. Recognizing the fact that in most men erectile dysfunction is a multifactorial problem, we enrolled men with a broad variety of causes of erectile dysfunction. The identification of an organic abnormality does not establish it as the cause of erectile dysfunction.14 Conversely, failure to identify an organic cause does not prove a psychogenic origin. The International Index of Erectile Function (IIEF): a multidimensional scale for assessment of erectile dysfunction. Riley, AJ, Athanasiadis, L. Impotence and its non-surgical management.
- Sildenafil tablets can cause a sudden drop in blood pressure if combined with nitrates.
- Proper hydration helps ensure the effectiveness of sildenafil tablets.
- Reading the patient information leaflet helps understand the correct use of sildenafil.
Br J Clin Pract 1997;51:99-103 Any commercial reuse of NEJM Group content requires permission.
- Sildenafil tablets are available by prescription and should not be purchased from unverified sources.
- Store sildenafil tablets at room temperature away from moisture and heat.
- Do not split or crush sildenafil tablets unless specified by a doctor.
From the Department of Urology, Boston University Medical Center, Boston (I.G. ); the Department of Urology, University of California, San Francisco (T.F.L. ); the Department of Urology, University of Southern California, Los Angeles, and the Male Clinic, Santa Monica, Calif.
5.6 Combination with other PDE-5 Inhibitors
In the dose–response study, increasing doses of sildenafil (25 to 100 mg) were increasingly effective in improving the frequency of penetration and the maintenance of erections after penetration, the mean score for the erectile-function domain of the International Index, and the percentage of men reporting better erections. In the dose-escalation study, sildenafil treatment was associated with improvements in the frequency of penetration and the maintenance of erections after penetration. The therapeutic response to sildenafil was similar in men with various causes of erectile dysfunction. The mean scores after sildenafil therapy approached those of normal men of the same age. The men we studied had a normal level of sexual desire, as might be expected of men with erectile dysfunction who enter a clinical trial,13 and sildenafil did not alter that level.
Study of Dose–Response, Efficacy, and Safety
Successful sexual intercourse was therefore a key end point for these men. Overall, the results of the efficacy assessments demonstrated that sildenafil significantly improved erectile function and quadrupled the success of intercourse, with effectiveness maintained for at least six months. Its main adverse effects were headache, flushing, dyspepsia, and visual disturbances and were usually mild. Only one man with a visual disturbance discontinued treatment, and he also had flushing. Few men discontinued sildenafil, suggesting a relatively high level of drug tolerability and acceptance.
Statistical Analysis
No man had priapism after sildenafil treatment. Sildenafil has modest vasodilator properties but no effect on heart rate. The American Urological Association Panel on the Treatment of Organic Erectile Dysfunction stated that the ultimate goal is a therapy that is reliable, has minimal side effects, and is simple to use.6 Sildenafil appears to meet these specifications. Oral therapy permits discreet administration and is less invasive than some other treatment options, including injections into the corpus cavernosum, transurethral drug delivery, and prosthesis implantation. Goldstein, Lue, Padma-Nathan, Rosen, and Steers have served as consultants to Pfizer, manufacturer of sildenafil, as well as to other companies making products for the treatment of erectile dysfunction. (H.P.-N.); the Department of Psychiatry, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, N.J. ); the Department of Urology, University of Virginia, Charlottesville (W.D.S. Select the format you want to export the citation of this publication.
- Sildenafil tablets typically start working within 30 to 60 minutes after ingestion.
- The effects of sildenafil tablets can last up to 4-6 hours.
- Taking sildenafil with high-fat meals may delay its effectiveness.
Multi-view semi-supervised adversarial attention network for drug repurposing, Computer Methods and Programs in Biomedicine, 282, (109406), (2026). Multi‐Target Mechanisms of Moroccan Aphrodisiac Plants: An Integrative Computational and Phytochemical Investigation, Food Science & Nutrition, 14, 5, (2026). Artificial intelligence in drug research and development: a review of methods and applications in drug repurposing, Briefings in Bioinformatics, 27, 3, (2026).
Formats available
McCullough, New York; J. McMurray, Huntsville, Ala.; D.F. ; J Susset, Providence, R.I.; J. Tuttle, Lexington, Ky.; G. Wells, Birmingham, Ala.; C. Endocrine-metabolic crosstalk in erectile dysfunction: mechanistic insights and therapeutic implications, International Journal of Impotence Research, (2026). Therapeutic applications of phosphodiesterase inhibitors in male reproductive health: narrative review, Sexual Medicine Reviews, 14, 2, (2026). Oral suspension versus tablet sildenafil for erectile dysfunction: a prospective multicenter comparative study on patient satisfaction, International Journal of Impotence Research, (2026). Low‐intensity shockwave therapy for erectile dysfunction: An abridged Cochrane review, BJU International, 137, 6, (949-957), (2026). Current state of the problem, Andrology and Genital Surgery, 25, 4, (33-40), (2026). Emerging Trends and Research Focus in Erectile Dysfunction Treatment: A 1993–2023 Bibliometric Analysis, Andrologia, 2026, 1, (2026).
What Is Sex Time?
We are indebted to all the investigators who participated in the trials; to Dr. Ian Osterloh and Dr. David Cox of Pfizer for their help with the study design and logistics; to Dr. Michael Collins and Dr. Michael Smith of Pfizer for their assistance with data analysis; and to Dr.
How should I store sildenafil?
Patricia Leinen and Dr. Michael Sweeney for aid in the preparation of the manuscript. The other members of the Sildenafil Study Group are S. Auerbach, Newport Beach, Calif.; A.L. Burnett, Baltimore; R.
What are the serious side effects of sildenafil?
Castellanos, Fort Myers, Fla.; L. Charles, Stratford, N.J.; F. Eid, New York; R. Feldman, Waterbury, Conn.; W. Fitch III, San Antonio, Tex. Age > 65 years, hepatic impairment: 25 mg Severe renal impairment (CrCl tablet sildenafil 50 mg < 30 ml/min): 25 mg Moderate hepatic impairment: initial 5 mg, max 10 mg Mild, moderate, severe renal impairment: No adjustment Mild or moderate hepatic impairment: max 10 mg once daily Moderate renal impairment: initial 5 mg once daily, max 10 mg every 48 hours Severe renal impairment (CrCl < 30 ml/min) on hemodialysis: max 5 mg Sildenafil is used to treat erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. These medicines prevent an enzyme called phosphodiesterase type-5 from working too quickly. The penis is one of the areas where this enzyme works. Erectile dysfunction is a condition where the penis does not harden and expand when a man is sexually excited, or when he cannot keep an erection. When a man is sexually stimulated, his body's normal response is to increase blood flow to his penis to produce an erection. By controlling the enzyme, sildenafil helps to maintain an erection after the penis is stroked.