Smoking May Increase Effectiveness of Heart Drug
Half a pack of cigarettes per day can increase clopidogrel efficacy, study suggests
THURSDAY, April 9 (HealthDay News) -- Smoking at least half a pack of cigarettes a day increases the effectiveness of clopidogrel in patients who have had a heart attack, according to the results of a study published in the April 14 issue of the Journal of the American College of Cardiology.
Nihar R. Desai, M.D., from Brigham and Women's Hospital in Boston, and colleagues examined whether cigarette smoking affected the efficacy of clopidogrel in 3,429 patients with ST-segment elevation myocardial infarction who were randomized to placebo or clopidogrel as part of a clinical trial. They note that smoking induces an enzyme that activates clopidogrel, and an earlier study had shown that smoking at least 10 cigarettes per day resulted in greater inhibition of platelet aggregation.
The researchers found that although clopidogrel was effective in reducing the rate of closed infarct-related artery or death or myocardial infarction before angiography, the drug was even more effective in the 1,491 patients who smoked at least 10 cigarettes per day (adjusted odds ratio, 0.49 versus 0.72). Clopidogrel was also more effective in reducing the risk of cardiovascular death, myocardial infarction, or urgent revascularization in 30 days in patients who smoked at least 10 cigarettes per day (adjusted odds ratio, 0.54 versus 0.98).
"Cigarette smoking seems to positively modify the beneficial effect of clopidogrel on angiographic and clinical outcomes," Desai and colleagues conclude. "This study demonstrates that common clinical factors that influence the metabolism of clopidogrel might impact its clinical effectiveness."
The trial was funded by Bristol-Myers Squibb. Many of the authors reported receiving research grants or honoraria from pharmaceutical and biotechnology companies, including Bristol-Myers Squibb.