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VIAGRA demonstrated efficacy in studies of men with ED after 3DCRT, I-125, and brachytherapy.1-3*†‡
In a study, VIAGRA improved ability to achieve erection and frequency of satisfying intercourse after radical prostatectomy.4§
Proven efficacy for men with ED
- In a pooled analysis of 26 flexible-dose studies, an 81% improvement from baseline in the ability to penetrate (P<.0001) and a 104% improvement from baseline in the ability to maintain an erection (P<.0001) were reported by men with ED taking VIAGRA, compared with 19% and 26% for placebo, respectively5||
According to a study, what percentage of men with ED after undergoing radiotherapy were able to have successful intercourse with VIAGRA?
Answer: D
In a study, 74% of men with ED after undergoing I-125 radiotherapy were able to have successful intercourse with VIAGRA.2
Please scroll to see Indication and Important Safety Information.
Indication
VIAGRA is indicated for the treatment of erectile dysfunction (ED).
Important Safety Information
The use of VIAGRA and organic nitrates in any form, at any time, is contraindicated.
Before treating ED, physicians should consider the impact of resuming sexual activity and the mild and transient vasodilatory effects of VIAGRA on blood pressure. Physicians should carefully consider whether patients with underlying cardiovascular disease or other more unusual conditions could be adversely affected by vasodilatory effects, especially in combination with sexual activity.
As there have been infrequent reports of prolonged erections lasting more than 4 hours or priapism with all ED treatments in this drug class, patients should be advised to seek immediate medical attention should these occur. Erections lasting longer than 6 hours can result in penile tissue damage and long-term loss of potency.
Use a starting dose of 25 mg for patients who may have increased plasma levels (age >65, hepatic impairment, severe renal impairment, and concomitant use of potent CYP450 3A4 inhibitors). Patients taking ritonavir should not exceed 25 mg in a 48-hour period.
Patients with the following characteristics (recent serious cardiovascular events, hypotension or uncontrolled hypertension, or retinitis pigmentosa) did not participate in pre-approval clinical trials. In these patients, physicians should prescribe VIAGRA with caution.
Non-arteritic anterior ischemic optic neuropathy (NAION) has been reported rarely post-marketing in temporal association with the use of PDE5 inhibitors, including VIAGRA. It is not possible to determine if these events are related to PDE5 inhibitors or to other factors. Physicians should advise patients to stop use of PDE5 inhibitors, including VIAGRA, and seek medical attention in the event of sudden loss of vision.
Sudden decrease or loss of hearing has been reported in temporal association with the intake of PDE5 inhibitors, including VIAGRA. It is not possible to determine whether these events are related directly to the use of PDE5 inhibitors or to other factors. Physicians should advise patients to stop taking PDE5 inhibitors, including VIAGRA, and seek prompt medical attention in the event of sudden decrease or loss of hearing.
In a controlled interaction study of VIAGRA and amlodipine, the mean additional reduction in supine blood pressure was 8 mm Hg systolic and 7 mm Hg diastolic.
Physicians should advise patients of the potential for PDE5 inhibitors, including VIAGRA, to augment the blood pressure lowering effect of alpha blockers and anti-hypertensive medications. In some patients concomitant administration of a PDE5 inhibitor and alpha blocker may lead to symptomatic hypotension. Patients should be stable on alpha-blocker therapy prior to initiating VIAGRA treatment and VIAGRA should be initiated at the lowest dose (25 mg).
Physicians should inform patients not to take VIAGRA with other PDE5 inhibitors, including REVATIO, as the safety and efficacy in these combinations have not been studied.
Use of VIAGRA offers no protection against sexually transmitted diseases, including the human immunodeficiency virus (HIV); therefore, physicians should consider counseling their patients about protective measures.
The most common side effects of VIAGRA were headache (16%), flushing (10%), and dyspepsia (7%). Adverse events, including visual effects (3%), were generally transient and mild to moderate.
Full Prescribing Information and Patient Package Insert.
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STUDY DESCRIPTIONS
*Results from a double-blind, flexible-dose, 12-week crossover study of patients with erectile dysfunction (ED) after three-dimensional conformal external beam radiotherapy (3DCRT) (N=60). After a mean duration of 39 months, patients were started on VIAGRA 50 mg (n=30) or placebo (n=30). After a 2-week follow-up, patients were titrated to VIAGRA or placebo 100 mg, if necessary, for the next 4 weeks. Crossover took place at 6 weeks, with patients starting on 50 mg again, titrating up to 100 mg or down to 25 mg at a follow-up 2 weeks later, if necessary. Patients responded to International Index of Erectile Function (IIEF) questions 3 and 4 at baseline, and at 2, 6, 8, and 12 weeks of the double-blind phase. Responses were graded on a scale of 1 (almost never or never) to 5 (almost always or always). Q3: "When you attempted sexual intercourse, how often were you able to penetrate (enter) your partner?" Baseline: 1.5, after VIAGRA: 2.8 (P<.001), after placebo: 1.6 (P<.01). Q4: "During sexual intercourse, how often were you able to maintain your erection after you had penetrated (entered) your partner?" Baseline: 1.3, after VIAGRA: 2.6 (P<.001), after placebo: 1.5 (P<.01). Results based on reported mean scores. Following the 12-week study, patients could enroll in a 6-week open-label phase (n=46), starting with VIAGRA 50 mg for 2 weeks and titrating up to 100 mg, if necessary. Patients responded to IIEF questions 3 and 4 at 2 and 6 weeks after the open-label period. IIEF Q3: Baseline: 1.5, after 2 weeks with VIAGRA: 2.6, after 6 weeks with VIAGRA: 3.2. Q4: Baseline: 1.3, after 2 weeks with VIAGRA: 2.6, after 6 weeks with VIAGRA: 3.2. Results based on reported mean scores. After 2 years, all participants (N=60) were sent a questionnaire. Fifty questionnaires were returned (2 participants died, 1 was lost to follow-up, and 7 did not respond). Of these, 24% (n=12) were still using VIAGRA (24% discontinued because of cost and 16% because of side effects—dyspepsia, headache).
†Results from a prospective study of 86 patients who experienced a loss of sexual potency after undergoing iodine-125 (I-125) seed radiotherapy for the treatment of low-grade, clinically localized prostate cancer. Forty-three self-selected, nonrandomized patients began treatment with VIAGRA 50 mg at least 6 months after implantation. At a minimal follow-up of 6 months after the start of treatment, patients were titrated to 100 mg if they did not respond positively to VIAGRA. Response was measured using the IIEF-15 questionnaire, and efficacy was measured using the Erectile Dysfunction Inventory Treatment Satisfaction (EDITS) questionnaire. A separate questionnaire was used to determine partner/spousal sexual satisfaction. Patients completed the IIEF questionnaire and their partners completed the partner/spousal questionnaire before seed implantation and at a mean interval of 36 weeks after implantation (before taking VIAGRA). At 4 years, patients and their partners completed all 3 questionnaires again. Of the 43 men, 74% (n=32) responded positively to (had successful vaginal intercourse with) VIAGRA at 4 years.
‡Results from an open-label, nonrandomized study of 62 men taking VIAGRA 50 mg or 100 mg who had undergone transperineal ultrasound-guided brachytherapy for clinical T1/T2 adenocarcinoma of the prostate gland who experienced ED either before implantation (n=14) or after implantation (n=48). Positive response to VIAGRA was defined as at least 3 erections in 1 month that were sufficient for penetration and able to be maintained. Responders waited a mean of 16.4 months after surgery before beginning treatment with VIAGRA.
§Results taken from an open-label study of 91 men with severe ED following RP taking VIAGRA. Patients were stratified according to the type of nerve-sparing (NS) procedure (bilateral, unilateral, or non-NS). At least 3 months postsurgery, patients were started on VIAGRA 50 mg, with titration to 100 mg if necessary. Men completed the IIEF-15 questionnaire at baseline after surgery. At 1 year of treatment, patients responded to the IIEF-15 and the EDITS questionnaires, and their partners responded to the partner/spousal satisfaction questionnaire. Forty-eight men (52%) were identified as "positive responders" (having successful vaginal intercourse). These 48 men and their partners were sent a second round of surveys at 3 years, and 43 patients completed and returned them. Results illustrate patients' responses to question 2 of the IIEF. Twelve of those 43 patients had discontinued treatment at 3 years for the following reasons: 6 due to a return of natural erections sufficient for vaginal intercourse (mean use 2.1 years), 5 due to a loss of efficacy (mean use 1.5 years), and 1 because his spouse had died.
References
- Incrocci L, Hop WCJ, Slob AK. Efficacy of sildenafil in an open-label study as a continuation of a double-blind study in the treatment of erectile dysfunction after radiotherapy for prostate cancer. Urology. 2003;62(1):116-120.
- Raina R, Agarwal A, Goyal KK, et al. Long-term potency after iodine-125 radiotherapy for prostate cancer and role of sildenafil citrate. Urology. 2003;62(6):1103-1108.
- Merrick GS, Butler WM, Lief JH, Stipetich RL, Abel LJ, Dorsey AT. Efficacy of sildenafil citrate in prostate brachytherapy patients with erectile dysfunction. Urology. 1999;53(6):1112-1116.
- Raina R, Lakin MM, Agarwal A, et al. Long-term effect of sildenafil citrate on erectile dysfunction after radical prostatectomy: 3-year follow-up. Urology. 2003;62(1):110-115.
- Data on file. Pfizer Inc, New York, NY.
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