Alcohol can interact with many medicines, either increasing side effects like drowsiness and dizziness, reducing how well the medicine works, or in some cases causing serious reactions. Medicines that affect the brain, such as sleeping tablets, strong painkillers, anti-anxiety and some mental health medicines, can be made dangerously stronger by alcohol.
Some medicines carry specific warnings against any alcohol, including certain antibiotics and a few others that can cause severe nausea, flushing or worse when combined with drink. Others, like some painkillers, raise the risk of stomach or liver problems when mixed with regular alcohol.
The safest move is to read the leaflet and ask your pharmacist about your specific medicine before drinking. If a medicine carries a clear no-alcohol warning, follow it. When you are unsure, avoid alcohol until you have checked.