A benefit-risk assessment of agents used in the secondary prevention of stroke.

Stroke is a major cause of morbidity and mortality. Full assessment of stroke or transient ischaemic attack (TIA) patients is required to identify all risk factors and apply appropriate secondary preventative strategies. Antiplatelet therapies are effective in the secondary prevention of ischaemic stroke and can be justified despite adverse effects such as gastrointestinal haemorrhage. Aspirin (acetylsalicylic acid), aspirin plus dipyridamole, ticlopidine and clopidogrel are all of value but their adverse effect profiles vary significantly. Combinations of antiplatelet agents may offer additional benefit but not all combinations have been studied in stroke patients. Anticoagulation with agents such as warfarin is effective with coexisting atrial fibrillation and other conditions predisposing to cardioembolic stroke. Antihypertensive agents have been extensively studied in the primary prevention of stroke; however, relatively few trials of antihypertensive agents in the secondary prevention of stroke are available. The incidence of adverse effects of antihypertensive agents is relatively low and the benefit-risk profile would tend to favour their use in the secondary prevention of stroke. Recent studies of ACE inhibitors have identified an important role for these agents in the secondary prevention of stroke even in those who are normotensive and in those who have had a haemorrhagic stroke. The incidence of serious adverse effects with ACE inhibitors appears relatively low. Lipid-lowering agents may have a role to play in certain groups of patients with stroke. The incidence of adverse effects is relatively low with HMG-CoA reductase inhibitors. Cigarette smoking is an important risk factor for stroke and evidence is available that smoking cessation does reduce the individual's risk of stroke. Pharmacological agents are available to help smoking cessation. In patients with diabetes mellitus, intensive regimens with insulin and oral hypoglycaemic agents have so far not definitively been shown to reduce the incidence of macrovascular complications such as stroke. Tight glycaemic control has been shown to improve microvascular complications such as retinopathy, nephropathy and neuropathy and hence this is reason enough to advocate the use of these agents. Future developments in the treatment of diabetes may help. Secondary prevention of stroke has improved greatly over the past decade and hopefully will continue to improve. The use of pharmacological agents available currently and in the future will be clarified and refined as further clinical trials report.