A male client with a history of cocaine addiction is admitted to the coronary care unit for evaluation of substernal chest pain. The electrocardiogram (ECG) shows a 1-mm ST-segment elevation of the anteroseptal leads and T-wave inversion in leads V3 to V5. Considering the client’s history of drug abuse, nurse Greg expects the physician to prescribe:
A. Lidocaine (Xylocaine).
B. Procainamide (Pronestyl).
C. Nitroglycerin (Nitro-Bid IV).
D. Epinephrine.
Correct Answer: C. Nitroglycerin (Nitro-Bid IV).
The elevated ST segments in this client’s ECG indicate myocardial ischemia. To reverse this problem, the physician is most likely to prescribe an infusion of nitroglycerin to dilate the coronary arteries. Nitroglycerin is a vasodilatory drug used primarily to provide relief from anginal chest pain. Although nitroglycerin has a vasodilatory effect in both arteries and veins, the profound desired effects caused by nitroglycerin are primarily due to venodilation. Venodilation causes pooling of blood within the venous system, reducing preload to the heart, which causes a decrease in cardiac work, reducing anginal symptoms secondary to demand ischemia.
Option A: Lidocaine, formerly also referred to as lignocaine, is an amide local anesthetic agent. The drug is commonly used for local anesthesia, often in combination with epinephrine (which acts as a vasopressor and extends its duration of action at a site by opposing the local vasodilatory effects of lidocaine).
Option B: Procainamide is a cardiac drug that may be indicated for this client at some point but isn’t used for coronary artery dilation. Procainamide is a medication used in the management and treatment of ventricular arrhythmias, supraventricular arrhythmias, atrial flutter, atrial fibrillation, AV nodal reentrant tachycardia, and Wolf-Parkinson-White syndrome. It is a Class 1A antiarrhythmic agent.
Option D: If a cocaine user experiences ventricular fibrillation or asystole, the physician may prescribe epinephrine. However, this drug must be used with caution because cocaine may potentiate its adrenergic effects. Epinephrine is one of the most commonly used agents in a variety of settings as it functions as medication and hormone. It is currently FDA-approved for various situations, including emergency treatment of type 1 hypersensitivity reactions including anaphylaxis, induction, and maintenance of mydriasis during intraocular surgeries, and hypotension due to septic shock.