A health warning has been issued to elderly people after a survey found that more than a quarter of them ignored the advice of their doctors when taking drugs. In a poll of 304 people aged 60 or older at five elderly centres between July 21 and August 25, 71 per cent - or 216 people - were taking drugs. But 28 per cent of the 216 people taking medicine adjusted the dosage or stopped taking the drugs during the course of treatment without advising their doctors. The survey was conducted by Chinese University and the Pharmaceutical Society at centres for the elderly in Tsz Wan Shan, Tseung Kwan O, Wong Tai Sin, Chuk Yuen and Choi Hung. Vivian Lee Wing-yan, assistant professor at the university's school of pharmacy, said: 'If they don't follow doctors' instructions, the drugs may not effectively contain the disease. Those with high blood pressure may see their blood pressure level increase. And those with a high blood sugar level or a high cholesterol level may have a higher risk of heart attacks and strokes.' Professor Lee suggested patients put a mark on a calendar or jot notes in a diary each time they took drugs. The survey also found that a quarter of patients did not store their drugs properly. 'Many of them put all their drugs into a plastic bag. It is very confusing and can cause medication errors,' Professor Lee said. She said some pills for controlling blood pressure and blood sugar looked alike. 'They are all tiny, round and in white or pale yellow. It is difficult to distinguish them if they are put into the same bag. 'Drugs for controlling blood pressure are often taken in the morning and those for containing blood sugar levels should only be taken before meals. If patients mix them up and do not eat after taking blood sugar drugs, they may feel dizzy and their heartbeat may accelerate.' It was also found that 61 per cent of patients did not know the effects of the drugs they were taking, and 71 per cent were unaware of the side effects. Professor Lee suggested patients take the initiative to ask pharmacists about the effects and side effects of the drugs they were taking so they would have more confidence in the medications and would follow instructions.