Ventricular tachycardia after administration of sildenafil citrate: a case report
© Rasmussen et al; licensee BioMed Central Ltd. 2007
Received: 27 February 2007
Accepted: 13 August 2007
Published: 13 August 2007
It has not previously been reported that sildenafil citrate causes malignant arrhythmias in humans.
A 41-year-old man developed sustained ventricular tachycardia following sildenafil citrate administration.
It cannot be dismissed that this patient experienced ventricular tachycardia as an adverse effect of sildenafil citrate administration.
Concerns about the safety of sildenafil citrate (Viagra®) have previously been raised . Other case reports and studies have described electrophysiological changes associated with ventricular arrhythmias following administration of sildenafil citrate [2–4].
We describe a case of a young man with no cardiac history or family history of heart disease or sudden death, developing sustained ventricular tachycardia after ingestion of sildenafil citrate. This case highlights a potential adverse effect of sildenafil citrate and the possible morbidity and potential lethality associated with this adverse effect.
Discussion and conclusion
Sildenafil citrate is widely used to treat male erectile dysfunction and therapeutic uses for other diseases such as pulmonary hypertension are emerging. Sildenafil citrate has proven to be safe when used in the treatment of erectile dysfunction of organic, psychogenic or mixed causes . Concerns about the effects of phosphodiesterase-5 inhibitors on the heart and their safety in patients with cardiovascular disease have been raised. The concerns include effects on blood pressure, heart rate and cardiac electrophysiology. This led to the publishing of a report from the U.S. Food and Drug Administration, describing deaths in patients having been prescribed sildenafil citrate in the first period after the marketing from late March through mid-November 1998 . In this period, >6 million outpatient prescriptions were dispensed. Of the 130 confirmed deaths among men (mean age, 64 years) who received sildenafil citrate, 77 had cardiovascular events, including 41 with myocardial infarction and 27 with cardiac arrest. Cause of death was unknown in 48 and non-cardiac in 5 men. The time from drug ingestion to death or onset of symptoms leading to death was <5 hours for 44 men, later the same day; 6 men, the next day; 8 men, two to seven days later; 9 men and unknown for the remainder. Sildenafil citrate blocks the rapid component of the delayed rectifier potassium current in guinea pig hearts  and produces small but significant increases in the QTc interval in humans . Sildenafil has been reported to cause VT in pigs when administered in combination with a nitric oxide donor .
We conclude that our patient had no confirmable cardiac condition other than VT. The hypothesis, that this patient, with documented episodes of non-sustained VT, experienced an episode of sustained VT caused by sildenafil citrate lowering the VT threshold, cannot be dismissed.
Implantable cardioverter defibrillator
Full written consent has been obtained from the patient for submission of this manuscript for publication. Funding was neither sought nor obtained.
- Food and Drug Administration: Postmarketing safety of sildenafil citrate (Viagra). Summary of reports of death in Viagra users received from marketing (late March) through mid-November 1998. http://www.fda.gov/cder/consumerinfo/viagra/safety3.htm
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