Dear doctor;

Could you please give me some information on the antibiotic Metronidazole and why it is not advisable to drink alcohol when taking this drug? Sekibaka, Rulindo.

Dear Sekibaka,

Metronidazole is an anti infective drug used to treat infections by protozoa and anerobic bacteria. However, it causes flushing, dizziness, palpitations and breathlessness, among other uncomfortable reactions if taken along with alcohol. This is said to be due to its disulphiram like effect in the body. Disulphiram is a drug which causes intolerance to ethanol by increasing blood acetaldehyde levels if taken along with alcohol.

Though this effect regarding metronidazole is not substantiated by all studies, still it does cause uncomfortable reactions after concomitant alcohol use. Another hypothesis is that this effect could occur due to effect of metronidazole on brain serotonin (chemical involved in brain functions) levels.

Ideally, one should not use alcohol when on treatment with metronidazole. It should be avoided till 48 hours after finishing course of metronidazole.