Makindo Medical Notes

💊 About

Maraviroc is an oral CCR5 antagonist that blocks HIV entry into host cells. It is unique in that it only acts on CCR5-tropic (R5) viruses — not CXCR4-tropic or dual-tropic strains. Because of this, a tropism assay must be performed before use to confirm susceptibility. Always 🔗 check the BNF entry here for up-to-date dosing and cautions.

🧠 Mode of Action

• Acts as a chemokine receptor (CCR5) antagonist on CD4⁺ T-cells and macrophages.
• Prevents gp120-CCR5 binding, thereby blocking fusion and viral entry.
• May also have mild immunomodulatory effects through interference with chemokine signalling.

📋 Indications & Dose

• Used in combination antiretroviral therapy (ART) for adults infected with CCR5-tropic HIV-1.
• Typical dose: 300 mg twice daily; reduce to 150 mg BD if co-administered with strong CYP3A inhibitors (e.g. ritonavir).
• May be taken with or without food; tablets must be swallowed whole (do not crush or chew).
• Tropism testing (e.g. Trofile® assay) must confirm CCR5-tropic virus before starting.

⚠️ Interactions

• Extensively metabolised by CYP3A4 and a P-glycoprotein substrate.
• Levels ↑ by strong CYP3A4 inhibitors (ritonavir, ketoconazole); ↓ by inducers (rifampicin, carbamazepine).
• Check current interactions in the BNF.

🚧 Cautions

• Monitor for postural hypotension, particularly in those with cardiovascular disease.
• Use with caution in hepatic impairment — rare hepatotoxicity has been reported.
• Monitor for immune reconstitution inflammatory syndrome (IRIS) early in therapy.

⛔ Contraindications

• Not effective in patients whose HIV uses CXCR4 or dual (CXCR4/CCR5) co-receptors for entry.
• Known hypersensitivity to maraviroc or excipients.

💥 Side Effects

• Common: nasopharyngitis, cough, bronchitis.
• Postural hypotension, dizziness, gastrointestinal discomfort.
• Less common: raised liver enzymes, immune reconstitution syndrome, and ischaemic cardiac events.
• Rare: hepatitis and severe hypersensitivity reactions (rash, fever, eosinophilia).

📚 References

• BNF: Maraviroc
• British HIV Association (BHIVA) Guidelines, 2023.
• European AIDS Clinical Society (EACS) Guidelines, 2023.
• HIV i-Base: CCR5 antagonists in clinical use.