Retapamulin
Topical antibacterials
Topical antibacterials
A topical pleuromutilin antibiotic ointment for impetigo caused by Staphylococcus aureus or Streptococcus pyogenes; discontinued in the US.
Quick facts
- Group
- Topical antibacterials
- Target
- Bacterial 50S ribosomal subunit (peptidyl transferase centre)
- Used for
- Impetigo caused
- Key effects
- Irritation · Headache · Diarrhoea
- Monitor
- Healing of the impetigo lesions
- ATC
- D06AX13
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows retapamulin bound to the large (50S) ribosomal subunit of the bacterium Deinococcus radiodurans; it is not a human protein.
Retapamulin is a semisynthetic pleuromutilin, from a compound made by Pleurotus fungi. It binds a unique site on the bacterial 50S ribosomal subunit and blocks protein synthesis. It is active against gram-positive skin bacteria such as Staphylococcus aureus and Streptococcus pyogenes.
- Ointment reaches bacteria in impetigo crusts
- Retapamulin binds a unique site on the 50S ribosome
- Bacterial protein synthesis stops
- Impetigo lesions heal
Indications
- Impetigo caused by susceptible Staphylococcus aureus or Streptococcus pyogenes, in adults and children Impetigo →
Adverse effects
Common
- Irritation, burning, redness or itching where applied
- Headache
- Diarrhoea
Contraindications
- Hypersensitivity to retapamulin
Key interactions
- Strong CYP3A4 inhibitors
- Could raise the small absorbed amount; caution, especially in young children or on large areas of broken skin.
What is monitored
- Healing of the impetigo lesions
- Irritation or allergic reaction at the site
Administration and safety
- A thin layer is applied to the infected skin only, with a clean cotton swab.
- The area may be covered with a bandage or gauze, especially in young children.
- Kept out of the eyes, nose, mouth and genital mucosa, and not swallowed.
Pregnancy and breastfeeding
Little is absorbed from the skin; pregnancy and breastfeeding are mentioned to the clinician.
Nursing care
- Teach hand-washing after application and keeping the child's lesions covered to limit spread.
- Teach to report lesions that are spreading or not healing, or fever.
- Teach to report blistering, swelling or oozing at the site.
Pharmacokinetics
- Absorption
- Applied to the skin; absorption is low, but higher in children and on broken skin
- Metabolism
- CYP3A4 substrate
Test yourself
Think of the answer, then tap the question to see it.
Which bacterial structure does retapamulin bind?
A unique site on the 50S ribosomal subunit, blocking protein synthesis.
Which skin infection is retapamulin used for?
Impetigo caused by S. aureus or S. pyogenes.
From what natural source do pleuromutilins come?
Fungi of the genus Pleurotus.
Connections
← Back to the class: Topical antibacterials
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Retapamulin: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); RCSB PDB - 2OGO: The crystal structure of the large ribosomal subunit from Deinococcus radiodurans complexed with the pleuromutilin derivative retapamulin (SB-275833) (RCSB Protein Data Bank, 2007); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.