Patients should also be advised on alcohol intake with antibiotics. While it is sensible to avoid drinking alcohol when taking medication or feeling unwell, only metronidazole and tinidazole require complete abstinence from alcohol during the course and for 48 hours (metronidazole) and 72 hours (tinidazole) after its completion.

Anecdotally, many members of the public believe they cannot drink any alcohol with all antibiotics and stop courses early because of this.

Alcohol can cause a serious, disulfiram-like reaction when combined with metronidazole and tinidazole. Symptoms include breathlessness, headache, chest pain, skin flushing, increased or irregular heartbeat, light headedness, and nausea and vomiting. Other antibiotics that alcohol can interact with (and where caution is required) include:

• Co-trimoxazole: similar reaction to metronidazole or tinidazole, although this is very rare; alcohol in moderation does not normally cause a problem
• Linezolid: undistilled (fermented) alcoholic drinks such as wine, beer, sherry and lager can interact with linezolid
• Doxycycline: alcohol intake, especially in people with a history of chronic alcohol consumption, can reduce the effectiveness of doxycycline
• Erythromycin: alcohol may slightly reduce or delay its effect.