HIV Protease Inhibitor + Pharmacokinetic Enhancer (Antiretroviral)

Atazanavir with Cobicistat

Brand names: Evotaz

Adult dose

Dose: 1 tablet (atazanavir 300 mg / cobicistat 150 mg) once daily with food

Route: Oral

Frequency: Once daily with food

Clinical pearls

Fixed-dose combination offering convenience of single-tablet booster versus separate ritonavir
Cobicistat inhibits tubular creatinine secretion: expect creatinine rise of ~10–15 µmol/L without true renal function change — use cystatin C for true GFR assessment if needed
Otherwise, clinical profile very similar to atazanavir/ritonavir
BHIVA guidelines: Evotaz is an alternative boosted PI option
Take with food (protein-rich meal enhances absorption)

Contraindications

As per atazanavir — see atazanavir entry
Severe hepatic impairment
Creatinine clearance <70 mL/min if used with tenofovir disoproxil fumarate (renal safety)

Side effects

As per atazanavir (hyperbilirubinaemia, PR prolongation, nephrolithiasis)
Cobicistat inhibits tubular secretion of creatinine — serum creatinine rises ~0.1–0.2 mg/dL without true GFR change
Nausea, diarrhoea

Interactions

Very broad — cobicistat is a potent CYP3A4 inhibitor (but not CYP inducer, unlike ritonavir)
All interactions of atazanavir and additional cobicistat interactions apply
Refer to Liverpool HIV Drug Interactions Checker
PPIs — reduce atazanavir levels; H2 antagonists preferred if acid suppression needed

Monitoring

HIV viral load and CD4 count
Serum creatinine (anticipate modest rise — use cystatin C for true eGFR if needed)
Bilirubin, LFTs
Fasting lipids, glucose
Renal ultrasound if renal symptoms (nephrolithiasis)

Reference: BNF; BHIVA HIV Treatment Guidelines (2022); Liverpool HIV Drug Interactions Checker; https://bnf.nice.org.uk/drugs/atazanavir-with-cobicistat/. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways