Beta blockers for peripheral arterial disease

Intermittent claudication is the most common symptom of atherosclerotic peripheral arterial disease and results from decreased blood flow to the legs during exercise. Beta blockers are a large group of drugs that have been shown to decrease deaths in people with high blood pressure and coronary artery disease and are used to treat a number of disorders. They reduce heart activity but can also inhibit relaxation of smooth muscle in blood vessels, bronchi, and the gastrointestinal and genitourinary tracts.
The non-selective beta blockers propranolol, timolol and pindolol are effective at all beta-adrenergic sites in the body whereas some beta blockers are selective for the heart, such as atenolol and metoprolol.

Optimal therapy for people with either coronary artery disease or hypertension and intermittent claudication is controversial. This is because of the presumed peripheral blood flow consequences of beta blockers, leading to worsening of symptoms.

There is currently no evidence from randomised controlled trials that beta blockers adversely affect walking distance in people with intermittent claudication and beta blockers should be used with caution if clinically indicated. The review authors identified six randomised controlled trials that involved a total of only 119 people with mild to moderate peripheral arterial disease. The beta blockers studied were propranolol, pindolol, atenolol and metoprolol. None of the trials showed a clear worsening effect of beta blockers on time to claudication, claudication and maximal walking distances measured on a treadmill, calf blood flow, calf vascular resistance and skin temperature when compared with placebo. The trials did not report any adverse events or issues regarding taking the medication with the beta blockers studied.

Most of the trials were over 10 years old, reported on between 1980 and 1991. All were small and of poor quality. The drugs were administered for a short period of time (10 days to two months) and most of the outcome measures were reported in single studies. Additional drugs, calcium channel blockers and combined alpha and beta blockers, were also given in some of the trials.