Beta blockers have two key effects on the cardiac muscle; reducing the rate and force of myocardial contraction along with reducing the arterial blood pressure. Both effects reduce cardiac workload and myocardial oxygen demand.

CKS recommends that atenolol, metoprolol and bisoprolol be considered as first line beta blockers for the control of angina.¹ Atenolol, bisoprolol and metoprolol are cardioselective beta blockers that do not demonstrate any intrinsic sympathomimetic activity (ISA).

Beta blockers with ISA are considered to be less cardioprotective than those without ISA.

Beta blocker choice may be influenced by other co-morbidities. Patients who have previously had an MI may be prescribed metoprolol, propranolol, timolol or atenolol whilst in patients suffering heart failure bisoprolol, carvedilol or nebivolol may be more appropriate.¹

Acute attacks of angina are commonly associated with episodes of tachycardia; the rate controlling action of beta blockers is beneficial in countering this effect.

Reducing the heart rate increases the diastolic period which improves coronary perfusion by increasing the time for coronary blood flow.

Patients prescribed beta blockers should be counselled not to abruptly stop taking their treatment as this has been shown to increase the risk of cardiovascular events.

Common side effects associated with beta blockers include bradycardia, hypotension, cold extremities, fatigue, lethargy and impotence. Beta blockers can cause nightmares or sleep disturbances although this is less likely with water soluble beta blockers because of reduced passage across the blood brain barrier.

Non selective beta blockers can also mask the signs of hypoglycaemia so cardioselective agents should be used in patients with diabetes.

Patients should be advised to discuss their treatment with the GP if these side effects become problematic.