Pharmacokinetic enhancer (CYP3A4 inhibitor)
Cobicistat
Brand names: Tybost
Adult dose
Dose: 150mg OD with darunavir 800mg or atazanavir 300mg
Route: PO
Frequency: OD
Clinical pearls
- Boosts protease inhibitors / elvitegravir
- Apparent creatinine rise of ~10–15 µmol/L is benign; cystatin C unaffected
Contraindications
- Concurrent strong CYP3A4 inducers
- Severe hepatic impairment
Side effects
- Mild rise in serum creatinine (tubular secretion inhibition; not true GFR fall)
- GI upset
- Rash
Interactions
- Many — rivaroxaban, simvastatin, dabigatran, midazolam, ergot alkaloids; consult HIV pharmacist
Monitoring
- U&E
- LFTs
Reference: BNF; BHIVA guidelines; https://bnf.nice.org.uk/drugs/cobicistat/. Verify against your local formulary and the latest BNF before prescribing.
Related
Curated clinical cross-links plus same-class fallbacks.
Calculators
- SMART Risk Score for Recurrent CVD · Cardiovascular Risk
- PCSK9 Inhibitor Eligibility Assessment · Lipid Management
- Immune-Related Adverse Events (irAE) -- GI Toxicity Colitis Grading · Oncology-Related GI
- irAE Hepatitis Grading (CTCAE) · Immunotherapy
- DIPSS — Dynamic International Prognostic Scoring System for Myelofibrosis · Cancer Prognosis
- BALL Score for Relapsed/Refractory CLL · Leukaemia
Pathways
- Infective Endocarditis · ESC 2023 Infective Endocarditis Guidelines; NICE NG41
- Eczema Herpeticum · BAD; NICE CKS
- Suspected Bacterial Meningitis (Adult) · NICE NG240 (2024); NICE NG143 (paeds)
- Clostridioides difficile Colitis · NICE NG199 (2021); IDSA/SHEA 2021
- Returning Traveller — Fever · NaTHNaC; PHE; ESCMID 2018
- Malaria — Diagnosis & Management · PHE 2016; WHO 2023