Contraindications & cautions - antibiotics

The contraindications and cautions most relevant to antibiotics commonly prescribed for dental bacterial infections are presented here.

Refer to the BNF (available at www.medicinescomplete.com) for more comprehensive information on contraindications and cautions and advice on drug interactions and side effects.

Phenoxymethylpenicillin/amoxicillin

Contraindications

Do not prescribe phenoxymethylpenicillin or amoxicillin to people with a history of anaphylaxis, urticaria or rash immediately after penicillin administration as these individuals are at risk of immediate hypersensitivity, including anaphylaxis and rashes.

Cautions

Prescribe phenoxymethylpenicillin and amoxicillin with caution for:

people with hypersensitivity to cephalosporins since there is some evidence of partial cross allergenicity.
people with renal impairment. Dose reduction may be required in cases of severe renal impairment.
people taking warfarin, since phenoxymethylpenicillin or amoxicillin potentially alter the anticoagulant effect of warfarin. If either antibiotic is prescribed for patients taking warfarin, the INR should be checked 4-7 days after the antibiotic course has started.

Metronidazole

Contraindications

Do not prescribe metronidazole to:

people with known metronidazole or nitroimidazole hypersensitivity.
people taking warfarin.

Cautions

Metronidazole has a disulfiram-like reaction with alcohol therefore advise patients to avoid alcohol when taking metronidazole.