The risk of a second stroke is highest in the first days and weeks, which is why prevention starts on the ward rather than at a clinic appointment. Roughly one in ten people who have had a stroke or TIA have another within a year without treatment, and about one in four within five years; with the measures below, those figures fall by more than half. Every item here has a number behind it and a UK and a US position, which agree more than they differ.
1. The blood thinner, and it depends on the cause
No atrial fibrillation: an antiplatelet
Aspirin in the first two weeks, then clopidogrel 75 mg daily long term in the UK (aspirin with dipyridamole if clopidogrel is not tolerated); the US guideline accepts aspirin, clopidogrel or the combination with dipyridamole. After a minor stroke or high-risk TIA, the short course of two antiplatelets described in the hospital chapter for three to four weeks, then one. Two antiplatelets long term add bleeding without adding protection; if you are on both months later, ask why.
Atrial fibrillation: an anticoagulant, and sooner than it used to be
If AF has been found, an anticoagulant replaces the antiplatelet; it roughly halves the risk of another stroke where an antiplatelet barely dents it. A DOAC (apixaban, rivaroxaban, edoxaban or dabigatran) is first choice; warfarin for people with a mechanical valve, moderate-to-severe mitral stenosis or antiphospholipid syndrome. The old fear was that starting too soon would turn the stroke into a bleed, so guidelines said wait. Four trials have now tested that. ELAN (2023) started within 48 hours for smaller strokes and at day 6–7 for large ones, against later starts, and found no excess of bleeding; OPTIMAS, a UK trial in 2024, found starting within four days no worse than waiting seven to fourteen; and the 2025 pooled analysis of all four (CATALYST) found that starting within four days reduced the combined risk of recurrent stroke and bleeding at 30 days. The UK guideline, written before the last two, says within five days for a mild stroke and 5–14 days for a moderate or severe one; the evidence now supports the early end of that in nearly everyone. After a TIA, start immediately once a bleed is excluded.
After a bleed
Whether to restart a blood thinner after a haemorrhage is one of the hardest decisions in stroke medicine. For antiplatelets, the RESTART trial found restarting was safe and probably beneficial. For anticoagulants in AF after a bleed, trials completed in 2024 and 2025 (including ENRICH-AF and PRESTIGE-AF) found restarting reduced ischaemic events but increased re-bleeding, with the balance depending on where the bleed was: deep bleeds from blood pressure favour restarting; lobar bleeds from amyloid angiopathy do not. Left atrial appendage closure is the alternative where anticoagulation is judged too dangerous. This is a specialist decision, made with the person, and both guidelines say so.
2. Cholesterol: a target most people have never been told
A high-intensity statin (atorvastatin 80 mg, or 40–80 mg) for everyone with an ischaemic stroke or TIA, whatever the starting cholesterol, started in hospital. The SPARCL trial established it: stroke fell from 13.1% to 11.2% over five years on atorvastatin 80 mg. What matters as much as the drug is the target. The Treat Stroke to Target trial compared an LDL below 1.8 mmol/L with 2.6–3.6, and the lower target cut major cardiovascular events from 10.9% to 8.5% over three and a half years. The UK target is LDL below 1.8 mmol/L (non-HDL below 2.5), with ezetimibe added and then an injectable (a PCSK9 inhibitor or inclisiran) if the statin alone does not reach it. The US target is the same number in different units (LDL below 70 mg/dL). Lipids are rechecked at four to twelve weeks and the treatment stepped up until the target is met, which in practice is where most people are let down: a statin is started and never titrated. The mechanics are in the heart topic, which applies without alteration.
3. Blood pressure: the single largest lever
Hypertension is the biggest modifiable cause of first and recurrent stroke, and of nearly all haemorrhagic strokes. Treatment starts once the acute phase is over — usually within days, before discharge — and the target is lower than most people expect. UK: a clinic systolic below 130 mmHg (home readings below 125), except with severe narrowing of both carotids, where 140–150 is safer. US: below 130/80. The drug matters less than the number; a thiazide-like diuretic, an ACE inhibitor or an angiotensin blocker, and a calcium channel blocker are the usual building blocks, most people need two, and the timing of the dose (morning or evening) does not matter. A home monitor from the day of discharge is the practical step that makes the target real. The blood pressure chapter covers measurement and drugs.
4. Diabetes and glucose
HbA1c is checked in everyone; newly found diabetes after a stroke is common. Treatment follows the diabetes guidance, with two stroke-specific points. Pioglitazone reduced stroke or heart attack from 11.8% to 9.0% in people with insulin resistance but no diabetes (the IRIS trial) at the cost of weight gain, fluid retention and fractures; the US guideline calls it reasonable in that group and the UK guideline does not recommend it. And the GLP-1 drugs (semaglutide and its relatives) reduce cardiovascular events in people with established vascular disease and obesity, stroke included; both guidelines are catching up with that evidence, and the NHS restricts access.
5. The carotid, the heart and the hole
Three cause-specific treatments from the previous chapter, repeated here because they are prevention: carotid surgery within seven days for a 50–99% narrowing on the side of the stroke; anticoagulation for AF; PFO closure in the under-60s with no other cause. Each prevents more strokes than any pill in the person it applies to.
6. Daily life: what moves the risk
| Change | Effect | Note |
|---|---|---|
| Stopping smoking | The largest single behavioural change; risk falls towards a non-smoker's over about five years | Every service should offer help; vaping is a lesser harm than smoking, not a safe one |
| Blood pressure at home | Achieving the target is worth more than any other line in this table | Salt below 6 g a day; alcohol within 14 units; weight |
| Physical activity | Reduces recurrence and improves recovery; both guidelines recommend at least 150 minutes a week of moderate activity as function allows | Start in rehabilitation; a stroke is not a reason to sit |
| Mediterranean-style eating | The PREDIMED trial reduced stroke substantially in high-risk people; the effect is largest on stroke | See the eating topic |
| Alcohol | Heavy drinking raises haemorrhagic stroke risk sharply and ischaemic stroke moderately | Within 14 units; no drinking is safest after a bleed |
| Sleep apnoea | Common after stroke and worth treating for symptoms and blood pressure; the SAVE trial did not show CPAP reduced events | Ask if snoring, witnessed pauses or daytime sleepiness |
| Weight | Central adiposity raises risk; weight loss improves blood pressure and glucose | The GLP-1 route where eligible |
| The oestrogen pill and HRT | Contraindicated after an ischaemic stroke or TIA | Progestogen-only or non-hormonal methods; transdermal HRT only with specialist advice |
7. Mood, fatigue, cognition, driving and work
Depression affects around a third of people after a stroke, is under-recognised and is treatable; fatigue is one of the most disabling and least discussed consequences; cognitive impairment is common and should be screened for before discharge and at six months. None of these shows on any of the tests above, and every review should ask about them. Driving: after a stroke or TIA you must not drive a car for one month, and may resume without telling the DVLA if recovery is satisfactory and there is no other bar; bus and lorry licences need a year and a medical. Multiple TIAs, seizures, visual field loss and persistent weakness change the rules; check the DVLA guidance rather than assuming. Work: the UK guideline gained a return-to-work section in 2023; vocational rehabilitation is part of the pathway, not an extra.
8. When medicine stops, and what does not
After a stroke or TIA almost everyone stays on secondary prevention for life: the antithrombotic, the statin and the blood-pressure treatment are the three things with the best evidence for keeping you alive and independent. The exceptions where a drug is time-limited are specific: an antithrombotic after an arterial dissection usually stops at three to six months once the artery has healed; after a cerebral venous thrombosis anticoagulation runs three to twelve months; after PFO closure the antiplatelet is typically reviewed after six months by the cardiology team; and after a bleed there may be no antithrombotic at all. In each case the cholesterol and blood-pressure targets still apply, and so does everything in the table above. If you have been told you need no ongoing medicine, ask which of those situations you are in, and whether your LDL and blood pressure have been measured against the targets anyway.
Off medicine or on it, the things in your hands are the same: not smoking, blood pressure checked at home and kept under 130, 150 minutes a week of activity, a Mediterranean pattern of eating, alcohol within 14 units, sleep apnoea treated if present, and no combined oestrogen. Know the warning signs (the recognising chapter) and treat any new one as the emergency it is, on the same clock as the first.
9. What should be rechecked, and when
| When | What |
|---|---|
| Before discharge | Antithrombotic decided and started; statin started; blood pressure treatment started or planned; cause-finding complete or scheduled; swallow, mood and cognition screened; driving and work discussed; a home blood pressure monitor |
| Weeks 1–6 | Blood pressure repeatedly as drugs are adjusted; medicine tolerance and adherence; rehabilitation intensity; anticoagulation started if AF and not yet given |
| 6–12 weeks | Lipids on treatment against the 1.8 target and the next step if not met; HbA1c; kidney function on any new drug; blood pressure against target; the UK six-month review of needs is arranged |
| 6 months | The formal UK review: function, mood, cognition, fatigue, work, driving, carers; rhythm monitoring result if still pending |
| Annually | Blood pressure, lipids, HbA1c, kidney function, weight; an AF check; bleeding risk if anticoagulated; a medicine review asking whether each drug is still earning its place |
| Any time | New neurological symptoms are an emergency again, not a follow-up question. A second stroke is treated on the same clock as the first |
10. Where UK and US guidance differ
- Long-term antiplatelet. UK: clopidogrel; US: aspirin, clopidogrel or aspirin-dipyridamole are all acceptable.
- Anticoagulation timing. UK: 5 days mild, 5–14 moderate/severe (2023). US 2021 guidance similar. The 2025 pooled analysis supports within four days for most; neither guideline has yet incorporated it.
- Blood pressure target. UK systolic below 130; US below 130/80. Effectively the same.
- LDL target. Identical: 1.8 mmol/L and 70 mg/dL are the same number.
- Pioglitazone for insulin resistance without diabetes: US reasonable; UK not recommended.
- Carotid timing. UK seven days; US two weeks.
- Structured review. The UK six-month review is a national standard with no US equivalent.