Many nitrates, beta-blockers, and calcium-channel blockers have now been approved by the US Food and Drug Administration for treatment of stable angina pectoris. The table beginning on page 112 lists the individual drugs, their dosage, and their cost.

Every pharmaceutical drug is a dose-dependent poison. This article describes the clinical presentation and treatment of some dangerous overdoses commonly reported in adults.

Bepridil hydrochloride (Vascor - McNeil Pharmaceutical/Wallace Laboratories), a calcium-channel blocking agent chemically unrelated to verapamil (Calan, and others), nifedipine (Procardia, and others), or other drugs in this class, was recently approved by the US Food and Drug Administration for oral treatment of chronic stable angina pectoris. Because of its potential adverse effects, the labeling recommends reserving the drug for patients who fail to respond optimally to or are intolerant of other antianginal agents.

In a study of the interaction between alcohol and the calcium-channel blocker felodipine (Plendil), the grapefruit juice vehicle for the alcohol appeared to increase felodipine plasma concentrations. Subsequent studies have found that grapefruit juice increases plasma concentrations of several calcium-channel blockers and of some other drugs as well (DG Bailey et al, Clin Pharmacokinet, 26:91, 1994).

The importance of adequate control of hypertension in preventing organ damage and death is well established, but the choice of drugs is still controversial. Three recent drug trials, one supporting initial therapy with a diuretic, the second favoring an angiotensin converting enzyme (ACE) inhibitor, and the third showing equivalence between a calcium-channel blocker and an angiotensin-receptor blocker (ARB) have intensified the debate.

Many patients with hypertension require more than one drug to control their blood pressure. Tribenzor (Daiichi Sankyo), recently approved by the FDA for treatment of hypertension, combines the calcium channel blocker amlodipine (Norvasc, and others), the angiotensin receptor blocker (ARB) olmesartan (Benicar)and the most commonly prescribed diuretic, hydrochlorothiazide (HCTZ). Tribenzor is not approved for initial therapy, but is recommended for patients not adequately controlled on any 2-drug combination of a calcium channel blocker, an ARB or a diuretic.

The FDA has approved Tekamlo (Novartis), an oral fixed-dose combination of the direct renin inhibitor aliskiren (Tekturna) and the calcium channel blocker amlodipine (Norvasc, and others), for treatment of hypertension in patients not adequately controlled on monotherapy or already taking both drugs, and as initial therapy in those likely to need multiple drugs to control their blood pressure (BP). Both aliskiren and amlodipine are available in combinations with other antihypertensive agents.

Isosorbide mononitrate (ISMN; Ismo - Wyeth-Ayerst), an oral nitrate long available in Europe, was recently approved by the US Food and Drug Administration for prophylactic use in patients with chronic stable angina. ISMN is the major active metabolite of isosorbide dinitrate (ISDN; Isordil, and others).

Several recent case reports suggest that oral sildenafil may be effective for treatment of pulmonary arterial hypertension (PAH). Sildenafil is currently marketed as Viagra for treatment of erectile dysfunction (Medical Letter 1998; 40:51).

Eplerenone (e pler' en one; Inspra - Pharmacia), an aldosterone receptor antagonist similar to spironolactone (Aldactone, and others), has been approved by the FDA, but not yet marketed, for treatment of hypertension. It has also been tried for treatment of heart failure.