Metronidazole 0.75–0.8% Gel (Topical)
Brand names: Metrogel, Anabact, Rozex
Topical metronidazole gel is a nitroimidazole antimicrobial applied to the skin; in the plastics and burns setting it is used chiefly to reduce malodour from heavily colonised or anaerobically infected wounds and fungating lesions.
Adult dose
Dose adjustments
No dose adjustment is stated; SPC §4.4 notes the elimination half-life of metronidazole is unchanged in renal failure, although such patients retain the metabolite (clinical significance not known), and that metronidazole and its metabolites are efficiently removed in patients undergoing haemodialysis
Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.
Contraindications
- Known hypersensitivity to metronidazole, parabens or any of the constituents
Side effects
- Dryness or irritation of the skin after application to unbroken skin
- Systemic metronidazole therapy may occasionally cause an unpleasant taste in the mouth, furred tongue, nausea, vomiting and gastro-intestinal disturbance
- Urticaria, angioedema and anaphylaxis (reported with systemic therapy)
- Rarely: drowsiness, dizziness, headache and ataxia
- Rarely: skin rash, pruritus and darkening of urine
Interactions
- Alcohol — patients are advised not to take alcohol during systemic metronidazole therapy because of the possibility of a disulfiram-like reaction
- Warfarin-type oral anticoagulants — some potentiation of anticoagulant therapy has been reported with metronidazole
- Phenobarbitone — patients receiving phenobarbitone metabolise metronidazole much faster than normal, reducing the half-life to 3 hours
Clinical monograph
How it works
Within anaerobic bacteria its nitro group is reduced to reactive intermediates that damage microbial DNA, suppressing the anaerobes responsible for wound odour.
Prescribing in practice
- It controls odour and surface anaerobic colonisation but is not a substitute for systemic antibiotics in invasive wound infection or burns sepsis, which need parenteral treatment.
- Apply to clean wound beds and cover with a non-adherent dressing; the gel is for cutaneous use and should be kept away from the eyes.
- Systemic absorption from intact-bordered wounds is low, so the disulfiram-like alcohol reaction is far less likely than with oral therapy, but caution remains over large denuded areas.
Monitoring
Monitor wound odour, surface appearance and the periwound skin for irritation, escalating to systemic assessment if signs of spreading or invasive infection develop.
Counselling the patient
- This gel is mainly to reduce wound smell and surface germs, not to treat a deep infection.
- Report increasing redness, pain, fever or spreading around the wound promptly.
- Avoid getting the gel in the eyes and follow the dressing routine shown by the team.
Evidence & guidelines
Topical metronidazole for malodorous wounds is supported by palliative wound-care guidance and longstanding clinical practice rather than large burns-specific trials.
Reference: NICE CKS Rosacea; BBA Fungating Wound Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).
Related
Curated clinical cross-links plus same-class fallbacks.