Effects of isradipine on intravenous cocaine-induced cardiovascular response: A pilot study

We examined the effects of isradipine, a dihydropyridine-class calcium chan nel antagonist, and effective antihypertensive medication on the presser ef fects of cocaine on cardiac function. Using continuous non-invasive cardiov ascular monitoring of heart rate, blood pressure, electrocardiographic reco rdings, and peripheral oxygen saturation, six healthy cocaine addicts recei ved the following treatments in blinded, crossover fashion: (a) placebo; (b ) intravenous cocaine (0.325 mg/kg iv), and (c) isradipine (10 mg p.o.) + c ocaine. While cocaine-taking was associated with a small increase in blood pressure, this effect was not significantly affected by isradipine. Isradip ine pretreatment was, however, associated with a significant reflex rise in heart rate following cocaine. Cocaine administration with or without israd ipine produced no clinically significant abnormalities of rhythm or conduct ion on the electrocardiogram and on peripheral oxygen saturation. While the se results should be considered preliminary, they do suggest that this isra dipine dose and/or dosing strategy does not have a clinically significant c ardioprotective effect during cocaine-taking. Copyright (C) 1999 John Wiley & Sons, Ltd.