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maraviroc

Brand: Selzentry, Celsentri

⚠ BBW Prototype Drug
Drug Class: CCR5 co-receptor antagonist (entry inhibitor)
Drug Family: antiretroviral
Subclass: HIV CCR5 antagonist
Organ Systems: infectious-disease

Mechanism of Action

Binds human CCR5 co-receptor (not the virus), preventing HIV-1 gp120 binding and viral entry into CD4+ T cells; ONLY effective against CCR5-tropic HIV — requires tropism testing before use.

human CCR5 co-receptor

Indications

  • HIV-1 infection in treatment-experienced patients with CCR5-tropic virus only (after tropism testing confirms CCR5-only tropism)

Contraindications

  • maraviroc hypersensitivity
  • CXCR4-tropic or dual/mixed-tropic HIV (testing required — ineffective and may allow CXCR4 virus to expand)

Adverse Effects

Common

  • cough
  • upper respiratory tract infections
  • rash
  • musculoskeletal symptoms

Serious

  • hepatotoxicity (especially with pre-existing liver disease)
  • orthostatic hypotension
  • cardiovascular events (safety signal in some trials)
  • immune reconstitution inflammatory syndrome

Pharmacokinetics (ADME)

Absorption moderate bioavailability (varies with dose — 23–33% at 300 mg); food has variable effect
Distribution extensively distributed; high protein binding
Metabolism hepatic CYP3A4 substrate; dose must be adjusted based on CYP3A4 inhibitor or inducer status of co-medications
Excretion fecal (76%) and urinary (20%)
Half-life 14–18 hours
Onset 0.5–4 hours
Peak 0.5–4 hours
Duration 12 hours
Protein Binding 76%
Vd moderate

Drug Interactions

Drug / Agent Mechanism Severity
ritonavir/cobicistat (CYP3A4 inhibitors) increase maraviroc exposure — reduce maraviroc dose to 150 mg BID major
rifampin (CYP3A4 inducer) reduces maraviroc by ~64% — increase dose to 600 mg BID major

Nursing Considerations

  1. Tropism testing (enhanced sensitivity Trofile assay or genotypic tropism assessment) must be performed BEFORE prescribing maraviroc; if mixed/CXCR4-tropic virus is present, maraviroc is contraindicated.
  2. Dose adjustment required based on concomitant CYP3A4 inhibitors or inducers; pharmacist review of the complete regimen is essential.
  3. Monitor LFTs; hepatotoxicity with allergic features can occur — instruct patients to report rash, jaundice, dark urine.
  4. Assess blood pressure; postural hypotension is a known adverse effect.

Clinical Pearls

  • Maraviroc targets the human CCR5 co-receptor rather than the virus — this makes it immune to direct viral resistance mutations but means viral tropism switching to CXCR4 renders it ineffective.
  • Maraviroc is the only approved CCR5 antagonist and represents a unique 'host-targeting' approach to HIV therapy; tropism testing cost and complexity limit its routine use to treatment-experienced patients with confirmed CCR5-tropic virus.

Safety Profile

Pregnancy generally-safe
Lactation avoid
Renal Adjustment Required
Hepatic Adjustment Required
TDM Not required

Concordance Terms

Cross-referenced clinical concepts — click any term to see all content where it appears.

CCR5 Co-receptor Antagonist (entry Inhibitor) HIV-1 Infection In Treatment-experienced Patients With CCR5-tropic Virus Only (after Tropism Testing Confirms CCR5-only Tropism)
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