Recognizing Drug Reactions Problems related to medicine become more likely as you get older. Aging affects the way your body absorbs, uses, and eliminates medications. It may be harder for your liver to break down medicines and clear them from your body. Your kidneys may be slower to eliminate drugs from your system. Medicines can therefore stay in your body longer and become a serious problem.
Drug action varies widely in older people.
That makes it hard for your doctor to predict your response to a medicine. Older people usually need less of a drug than younger people to get the desired effects and avoid overdoses. Any symptom, such as vomiting, breathing problems, headache, confusion, or drowsiness is severe or long-lasting. Symptoms develop soon after you have started taking a new medicine or after eating a certain food. Symptoms such as forgetfulness, depression, confusion, or fatigue develop slowly over a period of weeks or months.