indication

For the prevention and reversal of bronchospasm in patients 12 years of age and older with asthma and reversible bronchospasm associated with bronchitis and emphysema.

pharmacology

Bambuterol is a long acting beta2-adrenoceptor agonist used in the treatment of asthma. It is a prodrug of terbutaline. Bambuterol causes smooth muscle relaxation, resulting in dilation of bronchial passages.

mechanism of action

The pharmacologic effects of bambuterol are at least in part attributable to stimulation through beta-adrenergic receptors (beta 2 receptors) of intracellular adenyl cyclase, the enzyme that catalyzes the conversion of adenosine triphosphate (ATP) to cyclic AMP. Increased cyclic 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.

biotransformation

Hepatic, extensive. Further metabolized to terbutaline by plasma cholinesterase.

absorption

Bioavailability is 20% following oral administration.

half life

13 hours for bambuterol and 21 hours for the primary active metabolite terbutaline.