Drug Groups

approved

Description

A moderately lipophilic beta blocker (adrenergic beta-antagonists). It is non-cardioselective and has intrinsic sympathomimetic actions, but little membrane-stabilizing activity. (From Martindale, The Extra Pharmocopoeia, 30th ed, p638)

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.

Toxicity

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

Affected Organisms

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

Protein Binding

40%

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.

Distribution

* 2 L/kg

Clearance

* 50-300 mL/min [cirrhotic patients]

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