ABSTRACT & COMMENTARY
Nifedipine has been described in more than 40 medical articles as a therapy for hypertensive emergencies. The efficacy of the short-acting immediate-releaseformulations is well-documented, with significant decreases in blood pressures occurring within 5-10 minutes. There seems to be no difference in efficacy dependingon gender or age. The most common side effects are not life-threatening: flushing, headaches, and tachycardia.
Despite the common (almost "voodoo" or "black magic") practice of piercing a capsule and squeezing the pill under the tongue to release the medication, studieshave shown that absorption predominantly occurs in the intestine rather than sublingually.
The significant adverse effects of nifedipine fall into three main categories: those due to the rather dramatic drop in blood pressure, those due to the peripheralvasodilation stealing blood from other vascular beds, and reflex tachycardia from catecholamine release. Clinically, these manifest in neurologic events, coronaryevents, or myocardial ischemia. Several deaths have occurred.
Because of this, the Cardiorenal Advisory Committee of the Food and Drug Administration suggested abandoning the practice of using sublingual nifedipine in1985. (Grossman E, et al. JAMA 1996;276:1328-1331.)
COMMENT BY LEN SCARPINATO, DO
Those of you who have never used sublingual nifedipine to reduce blood pressure, please stand up. Since we have all remained seated, we all are culpable in someway or fashion, especially if we’ve used it in the last 10 years. However, with this article, and an accompanying editorial describing misuse of sublingual nifedipine,we should abandon this practice.
I recently led some Office Emergency workshops at the American Academy of Family Practice annual CME meeting. I found that more than two-thirds of theaudience continue to use sublingual nifedipine. Rather boisterous discussions occurred about the Vth Joint National Committee soft peddling the therapy ofpseudoemergencies and hypertensive urgencies. The committee defined hypertensive emergencies as elevated blood pressures showing target organ damage,usually requiring IV therapy and hospitalization. They feel pseudoemergencies and urgencies should probably not even be treated in an aggressive fashion (i.e., oraltherapy can work, there is no need to rapidly drop the blood pressure regardless of how high it is). Use of sublingual nifedipine in hypertensive emergencies wouldbe contraindicated because you need more precise control of the blood pressure reduction, and you don’t want to overshoot.
In a related editorial, Winker discusses the FDA process for failed new drug applications.1 She states that the practicing physician doesn’t learn of the potentiallyvaluable information. She does, however, say that the medical news staff of the AMA will be attending important FDA meetings on new labeling for alreadyapproved drugs and that this will be published in the Medical News and Perspectives section of the Journal of the American Medical Association as well asbeing on the Worldwide Web (www.ama-assn.org).
Reference
1. Winker. JAMA 1996;276;1342-1343.
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