Treatment of erectile dysfunction with sildenafil citrate (Viagra) in parkinsonism due to Parkinson's disease or multiple system atrophy with observations on orthostatic hypotension

摘要

OBJECTIVES—To assessthe efficacy and safety of sildenafil citrate (Viagra) in men witherectile dysfunction and parkinsonism due either to Parkinson'sdisease or multiple system atrophy.
METHODS—Twenty fourpatients with erectile disease were recruited, 12 with Parkinson'sdisease and 12 with multiple system atrophy, into a randomised, doubleblind, placebo controlled, crossover study of sildenafil citrate. Thestarting dose was 50 mg active or placebo medication with theopportunity for dose adjustment depending on efficacy and tolerability.The international index of erectile function questionnaire (IIEF) wasused to assess treatment efficacy and a quality of life questionnaireto assess the effect of treatment on sex life and whole life. Criteriafor entry included a definite neurological diagnosis and a standingsystolic blood pressure of 90-180 mm Hg and diastolic blood pressureof 50-110 mm Hg, on treatment if necessary. Blood pressure was takenat randomisation (visit 2) and crossover (visit 5) lying, sitting, andstanding, before and 1 hour after taking the study medication in hospital.
RESULTS—Sidenafilcitrate was efficacious in men with parkinsonism with a significantimprovement, as demonstrated in questionnaire responses, in ability toachieve and maintain an erection and improvement in quality of sexlife. In Parkinson's disease there was minimal change in bloodpressure between active and placebo medication. In multiple systematrophy, six patients were studied before recruitment was stoppedbecause three men showed a severe drop in blood pressure 1 hour aftertaking the active medication. Two were already known to haveorthostatic hypotension and were receiving treatment with ephedrine andmidodrine but the third had asymptomatic hypotension. However, theblood pressures in all three had been within the inclusion criterionfor the study protocol. Despite a significant postural fall in bloodpressure after sildenafil, all patients with multiple system atrophyreported a good erectile response and were reluctant to discontinue the medication.
CONCLUSIONS—Sidenafilcitrate (50 mg) is efficacious in the treatment of erectile dysfunctionin parkinsonism due to Parkinson's disease or multiple system atrophy;however, it may unmask or exacerbate hypotension in multiple systematrophy. As Parkinson's disease may be diagnostically difficult todistinguish from multiple system atrophy, especially in the earlystages, we recommend measurement of lying and standing blood pressurebefore prescribing sildenafil to men with parkinsonism. Furthermore,such patients should be made aware of seeking medical advice if theydevelop symptoms on treatment suggestive of orthostatic hypotension.