PINDOLOL

WARNINGS Cardiac Failure Sympathetic stimulation may be a vital component supporting circulatory function in patients with congestive heart failure, and its inhibition by beta-blockade may precipitate more severe failure. Although beta-blockers should be avoided in overt congestive heart failure, if necessary, pindolol can be used with caution in patients with a history of failure who are well-compensated, usually with digitalis and diuretics. Both digitalis glycosides and beta-blockers slow atrioventricular conduction and decrease heart rate. Concomitant use can increase risk of bradycardia. Beta-adrenergic blocking agents do not abolish the inotropic action of digitalis on heart muscle. In Patients Without A History of Cardiac Failure In patients with latent cardiac insufficiency, continued depression of the myocardium with beta-blocking agents over a period of time can in some cases lead to cardiac failure. At the first sign or symptom of impending cardiac failure, patients should be fully digitalized and/or be given a diuretic, and the response observed closely. If cardiac failure continues, despite adequate digitalization and diuretic, pindolol therapy should be withdrawn (gradually, if possible). Exacerbation of Ischemic Heart Disease Following Abrupt Withdrawal Hypersensitivity to catecholamines has been observed in patients withdrawn from beta-blocker therapy; exacerbation of angina and, in some cases, myocardial infarction have occurred after abrupt discontinuation of such therapy. When discontinuing chronically administered pindolol, particularly in patients with ischemic heart disease, the dosage should be gradually reduced over a period of 1 to 2 weeks and the patient should be carefully monitored. If angina markedly worsens or acute coronary insufficiency develops, pindolol administration should be reinstituted promptly, at least temporarily, and other measures appropriate for the management of unstable angina should be taken. Patients should be warned against interruption or discontinuation of therapy without the physician's advice. Because coronary artery disease is common and may be unrecognized, it may be prudent not to discontinue pindolol therapy abruptly even in patients treated only for hypertension. Nonallergic Bronchospasm (e.g., chronic bronchitis, emphysema) - Patients with Bronchospastic Diseases Should in General Not Receive Beta-Blockers Pindolol should be administered with caution since it may block bronchodilation produced by endogenous or exogenous catecholamine stimulation of beta 2 receptors. Major Surgery Because beta-blockade impairs the ability of the heart to respond to reflex stimuli and may increase the risks of general anesthesia and surgical procedures, resulting in protracted hypotension or low cardiac output, it has generally been suggested that such therapy should be gradually withdrawn several days prior to surgery. Recognition of the increased sensitivity to catecholamines of patients recently withdrawn from beta-blocker therapy, however, has made this recommendation controversial. If possible, beta-blockers should be withdrawn well before surgery takes place. In the event of emergency surgery, the anesthesiologist should be informed that the patient is on beta-blocker therapy. The effects of pindolol can be reversed by administration of beta-receptor agonists such as isoproterenol, dopamine, dobutamine, or norepinephrine. Difficulty in restarting and maintaining the heart beat has also been reported with beta-adrenergic receptor blocking agents. Diabetes and Hypoglycemia Beta-adrenergic blockade may prevent the appearance of premonitory signs and symptoms (e.g., tachycardia and blood pressure changes) of acute hypoglycemia. This is especially important with labile diabetics. Beta-blockade also reduces the release of insulin in response to hyperglycemia; therefore, it may be necessary to adjust the dose of antidiabetic drugs. Thyrotoxicosis Beta-adrenergic blockade may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism. Patients suspected of developing thyrotoxicosis should be managed carefully to avoid abrupt withdrawal of beta-blockade which might precipitate a thyroid crisis.

CONTRAINDICATIONS Pindolol tablets are contraindicated in: 1) bronchial asthma; 2) overt cardiac failure; 3) cardiogenic shock; 4) second and third degree heart block; 5) severe bradycardia. (See WARNINGS. )

OVERDOSAGE No specific information on emergency treatment of overdosage is available. Therefore, on the basis of the pharmacologic actions of pindolol, the following general measures should be employed as appropriate in addition to gastric lavage: Excessive Bradycardia: administer atropine; if there is no response to vagal blockade, administer isoproterenol cautiously. Cardiac Failure: digitalize the patient and/or administer diuretic. It has been reported that glucagon may be useful in this situation. Hypotension: administer vasopressors, e.g., epinephrine or norepinephrine, with serial monitoring of blood pressure. (There is evidence that epinephrine may be the drug of choice.) Bronchospasm: administer a beta 2 stimulating agent such as isoproterenol and/or a theophylline derivative. A case of an acute overdosage has been reported with an intake of 500 mg of pindolol by a hypertensive patient. Blood pressure increased and heart rate was ≥ 80 beats/min. Recovery was uneventful. In another case, 250 mg of pindolol was taken with 150 mg diazepam and 50 mg nitrazepam, producing coma and hypotension. The patient recovered in 24 hours.