indication

Used in the emergency treatment of cardiac arrhythmias.

pharmacology

Practolol is a beta-adrenergic receptor antagonist that has been used in the emergency treatment of cardiac arrhythmias. Beta blockers inhibit normal epinephrine-mediated sympathetic actions, but have minimal effect on resting subjects. That is, they reduce the effect of excitement/physical exertion on heart rate and force of contraction and dilation of blood vessels.

mechanism of action

Like other beta-adrenergic antagonists, practolol competes with adrenergic neurotransmitters such as catecholamines for binding at sympathetic receptor sites. Like propranolol and timolol, practolol binds at beta(1)-adrenergic receptors in the heart and vascular smooth muscle, inhibiting the effects of the catecholamines epinephrine and norepinephrine and decreasing heart rate, cardiac output, and systolic and diastolic blood pressure.

toxicity

Symptoms of overdose include abdominal irritation, central nervous system depression, coma, extremely slow heartbeat, heart failure, lethargy, low blood pressure, and wheezing.

drug interactions

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

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

Clonidine: Increased hypertension when clonidine stopped

Dihydroergotamine: Ischemia with risk of gangrene

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

Epinephrine: Hypertension, then bradycardia

Ergotamine: Ischemia with risk of gangrene

Fenoterol: Antagonism

Formoterol: Antagonism

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

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

Ibuprofen: Risk of inhibition of renal prostaglandins

Indomethacin: Risk of inhibition of renal prostaglandins

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

Methysergide: Ischemia with risk of gangrene

Orciprenaline: Antagonism

Oxprenolol: Antagonism

Pipobroman: Antagonism

Piroxicam: Risk of inhibition of renal prostaglandins

Prazosin: Risk of hypotension at the beginning of therapy

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

Terbutaline: Antagonism