Bambuterol

General information

The efficacy of long-acting β ₂ -adrenoceptor agonists in patients with chronic obstructive pulmonary disease remains unclear, but their role in treatment regimens, particularly in comparison with oral theophylline, has been reviewed [ ].

Bambuterol is a β ₂ -adrenoceptor agonist, a biscarbamate ester prodrug of terbutaline [ , ]. It is available as the hydrochloride salt in 10 and 20 mg tablets. It escapes first-pass elimination and is concentrated in lung tissue after absorption from the gastrointestinal tract. It is hydrolysed to terbutaline primarily by an enzyme, butyrylcholinesterase, found in lung tissue. Terbutaline is therefore formed preferentially in the lung, and as a result bambuterol should have a more selective effect than terbutaline. The effect of bambuterol lasts for 24 hours. Peak plasma concentrations of terbutaline occur 4–7 hours after the administration of bambuterol. Maximum therapeutic benefit occurs 1 week after starting treatment.

Except for suppression of plasma butyrylcholinesterase, the adverse effects of bambuterol are those of a β ₂ -adrenoceptor agonist and are related to the plasma concentration of terbutaline. Plasma butyrylcholinesterase returns to control values about 2 weeks after stopping treatment [ ].

Drug studies