Q My father, who is 80, is getting transient ischaemic attacks (TIAs), and his doctor has prescribed a small aspirin once a day. She has also asked him to keep a large aspirin in his wallet, to take if one of the attacks lasts longer than usual. Why is this? I thought aspirin could cause bleeding in the brain and make a possible stroke worse.

A Your doctor has been following the latest news about the use of aspirin to prevent, or minimize the effect of, an impending stroke. We have known for more than 40 years that aspirin prevents blood from clotting and also breaks down, or stops the extension of, clots that are forming in arteries. That’s why we give it to people with known heart disease who have a history of clots in the coronary arteries (producing heart attacks and acute chest pain). We advise people at risk to take a small dose of aspirin (75mg) at night, and to carry a 300mg tablet in their handbags or wallets to take whenever they get chest pain. The system has worked very well – in people who follow that advice the heart attack numbers and, if they do occur, their severity, have fallen steeply. The new advice is that we will get the same results if the system is used in people who have impending strokes (caused by clots in the arteries in the brain). We have been wary of giving this advice until now because a small number of strokes are not caused by clots, but by bleeds – blood escaping from ruptured arteries into the tissues of the brain. In theory aspirin would only make them worse by stopping the escaping blood from clotting. However that fear has been almost completely dispelled. There is no evidence that giving aspirin to a person with a cerebral bleed will worsen the effects of the bleed, and there is plenty of evidence that it will considerably lessen the damage to the brain caused by a stroke due to thrombosis (clot).

So you should know the warning signs of impending stroke – in other words, when should we take or give the aspirin? Episodes of dizziness, difficulty in speaking, loss of balance, even transient blindness, weakness in the face or a limb, perhaps temporary confusion, all of which quickly die away, leaving you normal again, can be signs that small clots are passing through your arteries, and so far are not ‘sticking and blocking’ them. In people who have an irregular heartbeat or have heart valve problems a clot can grow on the distorted valve or inside one of the heart chambers, from which small pieces may break off to be swept up into the brain. But the symptoms may simply come out of the blue. If you start to have these symptoms please see your doctor, who will put in motion a range of treatments to try to prevent a stroke (for example controlling blood pressure and heart rate) but it is up to you to manage your own aspirin treatment. Experts in heart and stroke problems swear by keeping a full 300mg aspirin tablet in their wallet or handbag just in case they are out and about when they themselves start to feel the signs of an impending stroke. It is a very small, but effective, piece of safety equipment.

ENDS