cobicistat + elvitegravir + emtricitabine + tenofovir disoproxil fumarate: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
cobicistat + elvitegravir + emtricitabine + tenofovir disoproxil fumarate: clinical details
Prescribing considerations
- Confirm the licensed population and absence of relevant resistance mutations.
- Assess renal and bone risk, chronic hepatitis B or C, significant liver disease, pregnancy potential and the full interaction profile.
- Avoid initiation during pregnancy and arrange prompt specialist review if pregnancy occurs.
- Stopping in HIV/HBV co-infection can precipitate severe hepatitis exacerbation.
Contraindications and cautions
- Hypersensitivity to an active substance or excipient.
- Previous discontinuation of tenofovir disoproxil because of renal toxicity.
- Specified CYP3A-sensitive medicines with serious toxicity risk, including alfuzosin, amiodarone, quinidine, simvastatin, lovastatin, oral midazolam and triazolam.
- Strong CYP3A inducers including rifampicin, carbamazepine, phenobarbital, phenytoin and St John’s wort.
- Dabigatran etexilate and sildenafil used for pulmonary arterial hypertension.
Monitoring
- Assess creatinine clearance, urine glucose and urine protein before treatment; monitor renal function, serum phosphate and urinalysis regularly.
- Interpret modest early creatinine increases in light of cobicistat’s inhibition of tubular creatinine secretion while remaining alert to tenofovir-associated tubulopathy.
- Investigate persistent bone pain, weakness, fractures or biochemical features of proximal tubulopathy.
- Monitor liver status closely if treatment is stopped in HIV/HBV co-infection.
- Review concomitant medicines whenever treatment changes.
Clinical pharmacology
Elvitegravir inhibits HIV integrase; emtricitabine triphosphate and tenofovir diphosphate inhibit reverse transcriptase and terminate viral DNA chains. Cobicistat inhibits CYP3A and several transporters, boosting elvitegravir while driving much of the interaction burden. Emtricitabine and tenofovir are predominantly eliminated renally.
Formulation and product differences
- The selected product is a fixed-dose film-coated tablet containing tenofovir disoproxil, not tenofovir alafenamide.
- The tablet should not be chewed or crushed, and component-specific adjustment is not possible.
- It contains lactose monohydrate and is essentially sodium-free.
cobicistat + elvitegravir + emtricitabine + tenofovir disoproxil fumarate interactions
Cobicistat causes numerous clinically important interactions. Check prescribed, over-the-counter and herbal products with the HIV team or pharmacist.
Rifampicin, carbamazepine, phenobarbital, phenytoin or St John’s wort
Can markedly reduce elvitegravir and cobicistat exposure, risking treatment failure and resistance; use is contraindicated.
Simvastatin or lovastatin
Cobicistat can greatly increase statin exposure and toxicity; use is contraindicated.
Mineral antacids, supplements, multivitamins, sucralfate or buffered products
Magnesium, aluminium, calcium, iron or zinc can reduce elvitegravir absorption.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.