indication

For the management of hypertension, edema, ventricular tachycardias, and atrial fibrillation.

pharmacology

Pindolol is a non-selective beta-adrenergic antagonist (beta-blocker) which possesses intrinsic sympathomimetic activity (ISA) in therapeutic dosage ranges but does not possess quinidine-like membrane stabilizing activity. Pindolol impairs AV node conduction and decreases sinus rate and may also increase plasma triglycerides and decrease HDL-cholesterol levels. Pindolol is nonpolar and hydrophobic, with low to moderate lipid solubility. Pindolol has little to no intrinsic sympathomimetic activity and, unlike some other beta-adrenergic blocking agents, pindolol has little direct myocardial depressant activity and does not have an anesthetic-like membrane-stabilizing action.

mechanism of action

Pindolol non-selectively blocks beta-1 adrenergic receptors mainly in the heart, inhibiting the effects of epinephrine and norepinephrine resulting in a decrease in heart rate and blood pressure. By binding beta-2 receptors in the juxtaglomerular apparatus, Pindolol inhibits the production of renin, thereby inhibiting angiotensin II and aldosterone production and therefore inhibits the vasoconstriction and water retention due to angiotensin II and aldosterone, respectively.

toxicity

LD₅₀=263 mg/kg (orally in rats). Signs of overdose include excessive bradycardia, cardiac failure, hypotension, and bronchospasm.

biotransformation

Hepatic. In man, 35% to 40% is excreted unchanged in the urine and 60% to 65% is metabolized primarily to hydroxy-metabolites which are excreted as glucuronides and ethereal sulfates.

absorption

Rapidly and reproducibly absorbed (bioavailability greater than 95%).

half life

3 to 4 hours

route of elimination

Pindolol undergoes extensive metabolism in animals and man. In man, 35% to 40% is excreted unchanged in the urine and 60% to 65% is metabolized primarily to hydroxy-metabolites which are excreted as glucuronides and ethereal sulfates. About 6% to 9% of an administered intravenous dose is excreted by the bile into the feces.

drug interactions

Acetohexamide: The beta-blocker, pindolol, may decrease symptoms of hypoglycemia.

Aminophylline: Antagonism of action and increased effect of theophylline

Chlorpromazine: Increased effect of both drugs

Chlorpropamide: The beta-blocker, pindolol, may decrease symptoms of hypoglycemia.

Clonidine: Increased hypertension when clonidine stopped

Dihydroergotamine: Ischemia with risk of gangrene

Dihydroergotoxine: Ischemia with risk of gangrene

Diltiazem: Increased risk of bradycardia

Disopyramide: The beta-blocker, pindolol, may increase the toxicity of disopyramide.

Dyphylline: Antagonism of action and increased effect of theophylline

Epinephrine: Hypertension, then bradycardia

Ergonovine: Ischemia with risk of gangrene

Ergotamine: Ischemia with risk of gangrene

Fenoterol: Antagonism

Formoterol: Antagonism

Gliclazide: The beta-blocker, pindolol, may decrease symptoms of hypoglycemia.

Glipizide: The beta-blocker, pindolol, may decrease symptoms of hypoglycemia.

Glisoxepide: The beta-blocker, pindolol, may decrease symptoms of hypoglycemia.

Glyburide: The beta-blocker, pindolol, may decrease symptoms of hypoglycemia.

Glycodiazine: The beta-blocker, pindolol, may decrease symptoms of hypoglycemia.

Ibuprofen: Risk of inhibition of renal prostaglandins

Indomethacin: Risk of inhibition of renal prostaglandins

Insulin Glargine: The beta-blocker, pindolol, may decrease symptoms of hypoglycemia.

Isoproterenol: Antagonism

Lidocaine: The beta-blocker increases the effect and toxicity of lidocaine

Mesoridazine: Increased risk of cardiotoxicity and arrhythmias

Methyldopa: Possible hypertensive crisis

Methysergide: Ischemia with risk of gangrene

Orciprenaline: Antagonism

Oxtriphylline: Antagonism of action and increased effect of theophylline

Pipobroman: Antagonism

Pirbuterol: Antagonism

Piroxicam: Risk of inhibition of renal prostaglandins

Prazosin: Risk of hypotension at the beginning of therapy

Procaterol: Antagonism

Repaglinide: The beta-blocker, pindolol, may decrease symptoms of hypoglycemia.

Salbutamol: Antagonism

Salmeterol: Antagonism

Terazosin: Increased risk of hypotension. Initiate concomitant therapy cautiously.

Terbutaline: Antagonism

Theophylline: Antagonism of action and increased effect of theophylline

Thioridazine: Increased risk of cardiotoxicity and arrhythmias

Tolazamide: The beta-blocker, pindolol, may decrease symptoms of hypoglycemia.

Tolbutamide: The beta-blocker, pindolol, may decrease symptoms of hypoglycemia.

Treprostinil: Additive hypotensive effect. Monitor antihypertensive therapy during concomitant use.

Verapamil: Increased effect of both drugs