Protease inhibitor (amprenavir prodrug)
Fosamprenavir
Brand names: Telzir
Adult dose
Dose: With ritonavir boost: 700mg BD + ritonavir 100mg BD; or 1400mg OD + ritonavir 200mg OD
Route: PO
Frequency: BD or OD
Clinical pearls
- Less commonly used now — newer agents preferred
- Sulphonamide cross-reactivity caution
Contraindications
- Severe hepatic impairment
- Concurrent simvastatin/lovastatin/midazolam (oral)/triazolam/ergot/amiodarone (high-dose)/St John's wort/rifampicin
Side effects
- Rash (sulphonamide derivative)
- GI upset
- Hyperlipidaemia
- Hepatotoxicity
- Nephrolithiasis
Interactions
- Many — refer to BHIVA / HIV pharmacist
- Strong CYP3A4 effects
Monitoring
- Viral load
- CD4
- LFTs
- Lipids
Reference: BNF; BHIVA; SmPC; https://bnf.nice.org.uk/drugs/fosamprenavir/. 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