HIV protease inhibitor (used as pharmacokinetic booster)
Ritonavir
Brand names: Norvir
Adult dose
Dose: As booster: 100mg PO OD-BD with other PI. Therapeutic: 600mg BD (rarely used)
Route: PO
Frequency: OD-BD
Clinical pearls
- Used to boost other PIs (e.g. atazanavir, darunavir); component of nirmatrelvir/ritonavir (Paxlovid)
- Major drug-interaction profile — always check
Contraindications
- Concurrent CYP3A4 substrates with narrow therapeutic index
- Severe hepatic impairment
- Hypersensitivity
Side effects
- GI upset
- Hepatotoxicity
- Hyperlipidaemia
- Insulin resistance
- Pancreatitis
- Drug interactions (extensive)
Interactions
- Many — potent CYP3A4 inhibitor
- Statins (limit/avoid)
- Amiodarone
- Triazolam
- Pimozide
- Ergot alkaloids
- Apixaban (caution)
Monitoring
- LFTs
- Lipids
- Glucose
Reference: BNF; BHIVA; UK Liverpool HIV interactions; https://bnf.nice.org.uk/drugs/ritonavir/. 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