The interaction of cigarette smoking and beta-adrenoceptor blockade.

The importance of the interaction between smoking and propranolol (metabolised in the liver) and atenolol (excreted almost entirely in the urine) was investigated in a double-blind placebo-controlled trial. Resting and exercise heart rates were significantly greater during smoking than no-smoking phases. Atenolol and propranolol significantly improved ST segment response after exercise whether or not the patients were smoking. Plasma propranolol significantly increased when patients stopped smoking whereas there was no such change in atenolol levels.