Drug Groups

approved

Description

A beta-adrenergic agonist used in the treatment of asthma and bronchospasms. [PubChem]

Indication

For the treatment of bronchospasm, chronic bronchitis, asthma, and emphysema.

Pharmacology

Orciprenaline (also known as metaproterenol), a synthetic amine, is structurally and pharmacologically similar to isoproterenol. Orciprenaline is used exclusively as a bronchodilator. The pharmacologic effects of beta adrenergic agonist drugs, such as orciprenaline, are at least in part attributable to stimulation through beta adrenergic receptors of intracellular adenyl cyclase, the enzyme which catalyzes the conversion of adenosine triphosphate (ATP) to cyclic- 3',5'- adenosine monophosphate (c-AMP). Increased c-AMP levels are associated with relaxation of bronchial smooth muscle and inhibition of release of mediators of immediate hypersensitivity from cells, especially from mast cells.

Toxicity

Symptoms of overdose include angina, hypertension or hypotension, arrhythmias, nervousness, headache, tremor, dry mouth, palpitation, nausea, dizziness, fatigue, malaise and insomnia. LD₅₀=42 mg/kg (orally in rat).

Affected Organisms

Biotransformation

Hepatic and gastric. The major metabolite, orciprenaline-3-0-sulfate, is produced in the gastrointestinal tract. Orciprenaline is not metabolized by catechol-0-methyltransferase nor have glucuronide conjugates been isolated to date.

Absorption

3% (oral bioavailability of 40%)

Half Life

6 hours

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