Intracerebral haemorrhage and subarachnoid haemorrhage are associated with considerable morbidity and mortality. Too often the focus is on acute treatment after a haemorrhage has occurred, instead of primary and secondary prevention. Medical therapies to control hypertension, achieve tobacco abstinence, and avoid excessive alcohol consumption can confer broad reductions in haemorrhage risk across pathophysiological subtypes. Judicious restriction of antiplatelet and anticoagulant therapies to only those individuals and those intensities for which they are indicated also can substantially reduce haemorrhagic stroke frequency. Specific endovascular and surgical therapies, judiciously employed, will further reduce risk of first or recurrent haemorrhage from structural vascular anomalies, including arteriovenous malformation, cavernous malformations, and saccular aneurysms. For unruptured intracranial aneurysms, features that favour consideration of preventive occlusion include include younger patient age, prior subarachnoid haemorrhage from a different aneurysm, familial intracranial aneurysms, large aneurysm size, irregular shape, basilar or vertebral artery location, and aneurysm growth on serial imaging. Among individuals who are technical candidates for either coiling or clipping, endovascular coiling is associated with a reduction in procedural morbidity and mortality but has a higher risk of recurrence.

For hypertensive patients without prior stroke, TIA, or other symptomatic vascular disease, anti-hypertensive therapy reducing SBP by 10 mm Hg, is associated with reductions in recurrent stroke (by about one-quarter) and of combined stroke, MI, and vascular death (by about one-fifth). Benefit extends across all ages, race-ethnicities, and pathological stroke subtypes. Combined pharmacological and non-pharmacological therapy to lower blood pressure is indicated in all individuals with SBP> 140 or DBP> 90, and in individuals with SBP 130–139 or DBP 80–89 who have additional vascular risk factors. Non-pharmacological blood pressure lowering is indicated in individuals with SBP 130–139 or DBP 80–89 without important additional vascular risk factors. After an ischaemic stroke or TIA, treatment may be gradually started as early as 24–72 hours after onset. The absolute benefits of antihypertensive therapy increase with greater reductions in BP, and are higher for preventing recurrent stroke than for preventing MI, in both primary and secondary prevention. The degree of BP reduction more greatly influences vascular event prevention than does pharmacological agent class. Nonetheless, unless otherwise indicated, beta-blockers are not a preferred agent, as they show less efficacy for stroke prevention. Calcium channel antagonists, ACE inhibitors, and thiazide diuretics are particularly well-studied.