Viagra passes initial UK safety test, more research needed
Cardiovascular events in users of sildenafil: results from first phase of prescription event monitoring in England
March 18, 2001. A study in this week's BMJ finds no evidence for a higher incidence of fatal heart attack or ischaemic heart disease among English men taking sildenafil (Viagra). Although reassuring, further evidence is needed to confirm these findings, the authors say.
Users of sildenafil were identified from NHS prescriptions in England. The researchers (whose disclose that their travel expenses have been paid by Pfizer) identified patients who had started on Viagra about five months earlier. Through the prescribing physician, they mailed them questionnaires requesting details of adverse medical events after the drug had been prescribed.
More than nine thousand questionnaires were sent out for patients who began sildenafil between September
1998 and March 1999. Over half the patients responded, and 5601 provided "usable information."
Most of the patients took the drug for impotence (63.4%) and 14.1% had diabetes. In all, ten fatal events from ischaemic heart disease were reported.
In more detail - non-fatal events were
angina (9), chest pain (19), ischaemic heart disease (5), and myocardial infarction (7). Fatal events were myocardial infarction (6) and ischaemic heart disease (4). One death was
certified as congestive cardiac failure/ischaemic heart disease after intercourse. Four of the
10 patients who died were known to have had diabetes. When compared with death rates in the general population of England in 1998, there was "no evidence for a higher incidence of mortality in this group."
The authors say that the results are reassuring but more research is needed to find out if all men using Viagra in the UK react like the men whose records were studied here.
This study was headed by Saad Shakir, Director, Drug Safety Research Unit, Bursledon Hall, Southampton, UK, and Lynda V Wilton, senior research fellow. They disclose that they have received financial support from Pfizer to attend
conferences overseas.
Cardiovascular events in users of sildenafil [Viagra] BMJ March 17 2001