Prinzmetal’s variant angina

Prinzmetal s variant angina, chronic stable (effort-associated) angina PO Initially, 10 mg 3 times a day. Increase at 7- to 14-day intervals. Maintenance 10 mg 3 times a day up to 30 mg 4 times a day. PO (Extended-Release) Initially, 30-60 mg/day. Maintenance Up to 120 mg/day. 

Mayer S, Hillis LD. Prinzmetal s variant angina. Clin Cardiol. 1998 21 243-246. 

McMahon MT, McPherson MA, Talbert RL, Greenberg B, Sheaffer SL. Diagnosis and treatment of Prinzmetal s variant angina. Chn Pharm 1982 l(l) 34-42. 

In Prinzmetal s variant angina, vasospasm results from a focal episodic spasm of a coronary artery, with or without an obstructing coronary artery lesion. 

Patients with variant (Prinzmetal s) angina or cocaine-induced ACS may benefit from calcium channel blockers as initial therapy because they can reverse coronary vasospasm. /J-Blockers generally should be avoided in these situations because they may worsen vasospasm through an unopposed /T-blocking effect on smooth muscle. 

Verapamil (Isoptin, Covera), in addition to its use as an antiarrhythmic agent, has been employed extensively in the management of variant (Prinzmetal s) angina and effort-induced angina pectoris (see Chapters 17 and 19). It selectively inhibits the voltage-gated calcium channel that is vital for action potential genesis in slow-response myocytes, such as those found in the sinoatrial and A-V nodes. 

All agents are also effective in the control of variant (Prinzmetal s) angina, in which spasm of the coronary arteries is the main factor. Their usefulness in the more complex unstable (preinfarction) angina is less definite, depending on the hemodynamic status and the susceptibility of the patient to infarction. 

Organic nitrates (and nitrites) are simple nitric and nitrous acid esters of alcohols. They differ in their volatility for example, isosorbide dinitrate is solid at room temperature, nitroglycerin is only moderately volatile, whereas amyl nitrate is extremely volatile. These compounds cause a rapid reduction in myocardial oxygen demand followed by rapid relief of symptoms. They are effective in stable and unstable angina, as well as Prinzmetal s or variant angina pectoris. 

Use PO Treatment of angina due to Half-life Onset Peaks Duration coronary artery spasm (Prinzmetal s 3-8 hours PO 30-60 6-12 h 24 hours variant angina), chronic stable minutes angina (effort-associated angina). IV Immediate Extended release Treatment of essential hypertension and angina. Parenteral Temporary control of rapid ventricular rate in atrial fibrillation/flutter. Rapid conversion of PSVT to normal sinus rhythm. 

Two groups of patients may benefit from calcium chaimel blockers as opposed to /8-blockers as initial therapy. Cocaine-induced ACS and variant (or Prinzmetal s) angina are two conditions in which coronary vasospasm plays an important role. Calcium channel blockers and/or NTG generally are considered the agents of choice in these... 

Nifedipine (10 to 20 mg t.i.d.) is indicated in vasospastic (Prinzmetal s or variant) angina. It may also be used in chronic stable angina (classical effort-associated angina) without vasospasm. Sustained release nifedipine (30 to 60 mg once daily) is used in hypertension. 

Although anecdotal evidence suggested that prazosin might be useful in the treatment of patients with variant angina (Prinzmetal s angina) due to coronary vasospasm, several small controlled trials have failed to demonstrate a clear benefit. Some studies have indicated that prazosin can decrease the incidence of digital vasospasm in patients with Raynaud s disease however, its relative efficacy as compared with other vasodilators (e.g., Ca -channel blockers) is not known. Prazosin may have some benefit in patients with other vasospastic disorders. Prazosin decreases ventricular arrhythmias induced by coronary artery ligation or reperfusion in laboratory animals the therapeutic potential for this use in humans is not known. Prazosin also may be useful for the treatment of patients with mitral or aortic valvular insufficiency, presumably because of reduction of afterload. 

Verapamil (80 mg p.o. q. 6 to 8 hours) is indicated in the management of Prinzmetal s or variant angina or unstable or chronic, stable angina pectoris verapamil (0.075 to 0.15 mg/kg rv pnsh over a 2-minnte period) is indicated in the treatment of supraventricnlar tachyarrhythmias verapamil (240 to 480 mg p.o. daily) is indicated in the prevention of recurrent paroxysmal supraventricular tachycardia verapamil (240 to 320 mg p.o. daily) is indicated in the control of the ventricular rate in digitalized patients with chronic atrial flatter and/or fibrillation and verapamil (80 mg p.o. t.i.d.) is indicated in the management of hypertension. 

FIGURE 103 Verapamil is used in the management of Prinzmetal s or variant angina. ATP = adenosine triphosphate SR = sarcoplasmic reticulum. 

Variant (Prinzmetal s) Angina Hypoxia and ischemia to myocardium is caused by vasospasm (rather than progressive narrowing of coronary arteries). Episodes may occur at rest, often at the same time each day. S-T elevation on ECG. 

Acikel S, Dogan M, Sari M, Kilic H, Akdemir R. Prinzmetal-variant angina in a patient using zolmitriptan and citalopram. Am J Emerg Med 2010 28(2) 257.e3-6. 

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