Side-effect profile of sildenafil citrate (Viagra) in clinical practice

OBJECTIVES

Sildenafil citrate (Viagra) has been shown to be an effective treatment for erectile dysfunction. Initial studies reported a high tolerability and low incidence of certain characteristic adverse reactions. We sought to evaluate the incidence of side effects of sildenafil citrate, independent of industry support and constraints, utilizing a heterogeneous cohort of patients from a university-based practice.

METHODS

A prospective, open-label, flexible-dose study of 256 patients treated with sildenafil citrate for erectile dysfunction was performed at a single institution. The patients were questioned explicitly about the occurrence of headache, flushing, dyspepsia, nasal congestion, visual changes, and other side effects.

RESULTS

The adverse reactions most commonly observed were flushing (30.8%), headache (25. 4%), nasal congestion (18.7%), and heartburn (10.5%). All events were short lived and mild in nature. In the present study, 31.6% of patients experienced one or more adverse events. However, no one withdrew from the study because of the severity of these events. There was a significant association between higher doses and the occurrence of side effects.

CONCLUSIONS

The incidence of adverse events attributable to sildenafil citrate may be higher than initially reported, but an explanation may be the methodology of data collection and the industry-independent nature of this study. The side-effect profile is dose related and mild. Sildenafil citrate remains a safe and well-tolerated treatment for erectile dysfunction.

Treatment of infertility due to anejaculation in the male with electroejaculation and intracytoplasmic sperm injection

PURPOSE

We tested the hypothesis that spinal cord injury and/or anejaculation affects the outcome of intracytoplasmic sperm injection (ICSI).

MATERIALS AND METHODS

From November 1993 to October 1998 we obtained and prospectively reviewed data on 34 ICSI cycles using electroejaculated sperm, 620 male factor infertility ICSI cycles using normal ejaculated sperm and 120 cases of obstructive azoospermia, in which microsurgical epididymal aspiration and testicular sperm extraction-ICSI were done in 93 and 27, respectively.

RESULTS

A total of 34 ICSI cycles were performed in 17 couples with male infertility due to anejaculation secondary to spinal cord injury in 10 patients and retroperitoneal lymph node dissection in 5, and idiopathic in 2. In all 17 couples at least 3 previous intrauterine insemination cycles had failed. After electroejaculation 11 men had oligozoospermia and 6 normal sperm density. Median sperm retrieval volume plus or minus standard deviation was 1.9 +/- 1.9 ml., median sperm concentration 70.7 +/- 60.2 x 106 sperm per ml., median motility 10.7% +/- 10.8% and median forward progression 2.3 +/- 0.5 (scale 1 to 4). In the anejaculation group ICSI resulted in a median fertilization of 60% +/- 28%, 15% pregnancies per cycle and 29% pregnancies per couple. In the control group of 620 ICSI cycles from ejaculated specimens obtained from male patients with infertility median fertilization was 58% +/- 26%, and there were 39% pregnancies per cycle and 47% pregnancies per couple. The rate of pregnancies per embryo transfer and per couple was higher in the control than in the electroejaculation-ICSI group (p <0.05). However, there was no statistically significant difference in the fertilization rate.

CONCLUSIONS

ICSI or in vitro fertilization is a viable alternative for patients with anejaculation in whom intrauterine insemination failed. While the fertilization rate is similar in these couples, the pregnancy rate is significantly lower than that achieved with ejaculated specimens from patients with severe male factor infertility. ICSI is a viable alternative for a patient with anejaculation in whom intrauterine insemination or in vitro fertilization failed.

Sildenafil citrate after radical retropubic prostatectomy

PURPOSE

Erectile dysfunction continues to be a significant problem for men after radical retropubic prostatectomy despite nerve sparing techniques. Sildenafil citrate (Viagra) has proved effective for erectile dysfunction in many men. We determine the efficacy of sildenafil in men with erectile dysfunction after radical retropubic prostatectomy and examine variables that may impact the response to treatment.

MATERIALS AND METHODS

A total of 84 men were prescribed sildenafil after radical retropubic prostatectomy and asked to complete a series of questionnaires, including the International Index of Erectile Function (IIEF), on erectile function before and after sildenafil administration. The importance of factors, such as patient age, time since surgery, degree of cavernous nerve sparing, preoperative prostate specific antigen, Gleason score, clinical and pathological stage, and baseline postoperative erectile function, was examined.

RESULTS

Of the 84 patients 45 (53%) had improved erections and 34 (40%) had improved ability for intercourse while taking sildenafil. Mean IIEF score for the erectile function domain increased from 9 to 14 (p <0.001). Orgasmic function (p = 0.004) and intercourse satisfaction (p = 0.009) also significantly improved. The degree of nerve sparing and baseline postoperative erectile dysfunction had a significant impact on the ability of sildenafil to improve erectile function (p = 0.010 and p <0.001, respectively) and total IIEF questionnaire responses (p = 0.031 and p <0.001, respectively). Age and pathological stage also appeared to have a significant effect.

CONCLUSIONS

Sildenafil improved erectile function and the ability to have intercourse in more than half of men after radical retropubic prostatectomy. Baseline postoperative erectile function, which is dependent on the degree of nerve sparing technique, significantly impacts the likelihood that patients will respond to sildenafil.