1 May 2026Oral drugs
Cloxacillin oral
Cloxacillin guidance for impetigo, with adolescent and adult dosing plus penicillin allergy precautions.
Prescription under medical supervision
This guide page is for structured reference only and does not replace a clinician, pharmacist, or emergency review. Dose choice, route choice, interactions, and safety decisions still need professional judgment.
Therapeutic action
Penicillin antibacterial.
Indications
Impetigo. Preferably use cefalexin for this indication.
Forms and strengths
- 250 mg and 500 mg capsules.
Dose and duration
- Child over 10 years: 15 mg/kg 3 times daily for 7 days, maximum 3 g daily.
- Adult: 1 g 3 times daily for 7 days.
- 10 to < 13 years and 30 to < 45 kg: 2 capsules of 250 mg 3 times daily or 1 capsule of 500 mg 3 times daily.
- 13 to < 15 years and 45 to < 55 kg: 3 capsules of 250 mg 3 times daily.
- Adult >= 55 kg: 4 capsules of 250 mg 3 times daily or 2 capsules of 500 mg 3 times daily.
Contra-indications, adverse effects, precautions
- Do not administer to patients with allergy to penicillin.
- Administer with caution to patients with allergy to cephalosporins because cross-sensitivity may occur, or severe renal impairment by reducing the dosage.
- May cause gastrointestinal disturbances, particularly diarrhoea, allergic reactions sometimes severe, and rarely haematological disorders.
- Do not combine with methotrexate because methotrexate toxicity increases.
- Pregnancy: no contra-indication.
- Breast-feeding: no contra-indication.
Dosage and duration
| Age | Weight | 250 mg capsule | 500 mg capsule |
|---|---|---|---|
| 10 to < 13 years | 30 to < 45 kg | 2 cap x 3 | 1 cap x 3 |
| 13 to < 15 years | 45 to < 55 kg | 3 cap x 3 | - |
| Adult | ≥ 55 kg | 4 cap x 3 | 2 cap x 3 |
Source
MSF Essential drugs practical guidelines (January 2026)
This page reproduces the structured reference information for this batch while leaving out the Storage and Remarks sections.
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