MARAVIROC
Clinical safety rating: safe
Animal studies have demonstrated safety
Selective, reversible, small-molecule antagonist of the chemokine receptor CCR5, preventing HIV-1 entry into CD4+ T cells by blocking gp120-CCR5 interaction.
| Metabolism | Metabolized primarily by CYP3A4, also by CYP3A5 and CYP2C9. Metabolites are largely excreted in feces (76%) and urine (20%). |
| Excretion | Renal excretion accounts for approximately 20% of the dose as unchanged drug; fecal elimination accounts for about 76% (mainly as metabolites). |
| Half-life | Terminal elimination half-life is 14-18 hours following oral administration, allowing for twice-daily dosing. |
| Protein binding | Approximately 76% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution is approximately 194 L (2.8 L/kg for a 70 kg individual), indicating extensive tissue distribution. |
| Bioavailability | Oral bioavailability is approximately 23-33% (with food; lower when fasted). |
| Onset of Action | Oral: Time to maximum plasma concentration (Tmax) is 0.5-4 hours; onset of antiviral effect is expected within days. |
| Duration of Action | Duration of action corresponds to dosing interval (12 hours) due to maintained trough concentrations; clinical effect persists with consistent dosing. |
300 mg orally twice daily
| Dosage form | TABLET |
| Renal impairment | GFR < 30 mL/min: not recommended unless co-administered with CYP3A4 inhibitor; if used, dose 300 mg once daily. GFR ≥ 30 mL/min: no adjustment. |
| Liver impairment | Child-Pugh A or B: no adjustment; Child-Pugh C: contraindicated due to increased exposure. |
| Pediatric use | Weight ≥ 40 kg: 300 mg twice daily; Weight 30-39 kg: 150 mg twice daily; not recommended for weight < 30 kg or age < 2 years. |
| Geriatric use | No specific dose adjustment; use with caution due to potential renal impairment and increased comorbidity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Strong CYP3A4 inhibitors or inducers require dose adjustment Can cause hepatotoxicity and orthostatic hypotension.
| Breastfeeding | No data on presence in human milk, effects on breastfed infant, or milk production. M/P ratio unknown. Due to potential for HIV transmission and adverse effects, breastfeeding should be avoided in HIV-infected women. |
| Teratogenic Risk | Pregnancy Category B. In animal studies, no evidence of teratogenicity at systemic exposures up to 19 times human AUC at recommended dose. No adequate human studies; however, use during pregnancy only if clearly needed. Risk cannot be ruled out, especially in first trimester. |
■ FDA Black Box Warning
Hepatotoxicity: Severe, potentially fatal liver injury (including elevated bilirubin, hepatitis, and hepatic failure) has been reported. Discontinue if signs/symptoms of hepatitis or liver injury occur.
| Common Effects | Cough |
| Serious Effects |
["Absolute: Coadministration with CYP3A4 inducers (e.g., rifampin, phenytoin, St. John's wort) due to decreased efficacy.","Absolute: Severe hepatic impairment (Child-Pugh class C).","Relative: Coadministration with CYP3A4 inhibitors (e.g., ketoconazole, atazanavir) requires dose adjustment.","Relative: High cardiovascular disease risk (consider alternative)."]
| Precautions | ["Hepatotoxicity: Monitor liver function tests at baseline and monthly for first 3 months, then periodically.","Cardiovascular events: Increased risk of myocardial infarction in patients with pre-existing cardiovascular disease or risk factors.","Hypotension and syncope: Use caution in patients with a history of syncope or receiving antihypertensives.","Immune reconstitution syndrome: May occur with initial therapy.","Pregnancy: Use only if benefit outweighs risk (pregnancy category B)."] |
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| Fetal Monitoring |
| Monitor hepatic function, especially in patients with underlying liver disease. Assess for signs of infection and immune reconstitution syndrome. In pregnancy, monitor HIV RNA and CD4 count. Fetal surveillance not specifically indicated but routine prenatal care recommended. |
| Fertility Effects | In animal studies, no adverse effects on fertility or reproductive performance. No human data; effect on fertility unlikely based on pharmacology. |