Antibiotics and alcohol: Should I avoid mixing them?

The effects of combining antibiotics and alcohol can vary, depending on the specific antibiotic.

Alcohol doesn't diminish the effectiveness of most antibiotics. However, antibiotics and alcohol can cause similar side effects, such as stomach upset, dizziness and drowsiness. When you combine antibiotics and alcohol, these side effects may increase.

A few antibiotics — such as metronidazole (Flagyl), tinidazole (Tindamax) and trimethoprim-sulfamethoxazole (Bactrim) — should not be mixed with alcohol because this may result in a more severe reaction. Drinking any amount of alcohol with these medications can result in side effects such as flushing, headache, nausea and vomiting, rapid heart rate, and shortness of breath. Keep in mind that some cold medicines and mouthwashes also contain alcohol. So check the label and avoid such products while taking these antibiotics.

Rarely, alcohol can reduce the effectiveness of certain antibiotics — such as doxycycline (Vibramycin, Doryx) — which means a higher dose may be required to achieve the same treatment benefit.

Keep in mind that alcohol can reduce your energy and delay how quickly you recover from illness. So, it may be best to avoid alcohol until you have finished your antibiotics and are feeling better.