HIV protease inhibitor (boosted) Pregnancy: Darunavir with low-dose ritonavir should be used in pregnancy only if potential benefit justifies potential risk. Darunavir/cobicistat should NOT be initiated during pregnancy (low darunavir exposure, ~90% reduction in Cmin; risk of virological failure and mother-to-child transmission) — switch to an alternative regimen. Women receiving darunavir are advised not to breast-feed.

Darunavir

Brand names: Prezista

Darunavir is an HIV protease inhibitor used, always boosted with a pharmacokinetic enhancer, as part of combination antiretroviral therapy for HIV infection.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 800 mg once daily (ART-naive); 600 mg twice daily (most ART-experienced)

Route: Oral

Frequency: Once or twice daily depending on treatment history

Must always be given with cobicistat or low-dose ritonavir as a pharmacokinetic enhancer and in combination with other antiretrovirals, taken with food. ART-naive adults: 800 mg once daily with cobicistat 150 mg once daily or ritonavir 100 mg once daily. ART-experienced adults with no darunavir resistance-associated mutations (DRV-RAMs) and HIV-1 RNA less than 100,000 copies/mL and CD4+ at least 100 cells x10^6/L: 800 mg once daily with cobicistat 150 mg or ritonavir 100 mg once daily. All other ART-experienced patients, or if genotype testing unavailable: 600 mg twice daily with ritonavir 100 mg twice daily. Also available as an oral suspension for patients unable to swallow tablets. Cobicistat is not indicated for twice-daily regimens or for children under 12 years weighing less than 40 kg. Paediatric (ART-naive, 3-17 years and at least 40 kg): 800 mg once daily with ritonavir 100 mg once daily, or with cobicistat 150 mg once daily in adolescents 12 years or older; not recommended below 3 years or under 15 kg.

Dose adjustments

Renal

No dose adjustment required for darunavir/ritonavir in renal impairment. Cobicistat has not been studied in patients receiving dialysis (no recommendation for darunavir/cobicistat); darunavir/cobicistat should not be initiated in patients with low creatinine clearance (SPC text truncated).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Severe (Child-Pugh Class C) hepatic impairment
Co-administration with strong CYP3A inducers (e.g. rifampicin, St John's Wort; also carbamazepine, phenobarbital, phenytoin when boosted with cobicistat) and with lopinavir/ritonavir
Co-administration with drugs highly dependent on CYP3A for clearance where raised levels cause serious/life-threatening events (e.g. alfuzosin, amiodarone, ergot derivatives, oral midazolam, triazolam, simvastatin, lovastatin, sildenafil for pulmonary arterial hypertension, ticagrelor, pimozide, colchicine in renal/hepatic impairment)

Side effects

Diarrhoea
Nausea
Rash
Headache
Vomiting

Interactions

Strong CYP3A inducers (rifampicin, St John's Wort, carbamazepine, phenobarbital, phenytoin): reduce darunavir/ritonavir/cobicistat exposure — contraindicated
Darunavir boosted with ritonavir/cobicistat inhibits CYP3A (and CYP2D6, P-gp): increases exposure of CYP3A/CYP2D6/P-gp substrates
Cobicistat inhibits tubular secretion of creatinine (modest rise in serum creatinine / fall in creatinine clearance)

Clinical monograph

How it works

It selectively inhibits the HIV-1 protease enzyme, preventing cleavage of viral polyproteins and thereby blocking production of mature, infectious virions.

Prescribing in practice

Darunavir must always be co-administered with a pharmacokinetic booster (ritonavir or cobicistat) to achieve effective plasma concentrations.
It contains a sulfonamide moiety, so use with caution in patients with known sulfonamide allergy and monitor for severe skin reactions.
Numerous clinically significant drug interactions occur via CYP3A4, so review concomitant medicines carefully before prescribing.

Monitoring

Monitor HIV viral load and CD4 count to assess response, together with liver function and metabolic parameters during treatment.

Counselling the patient

Take exactly as prescribed alongside the recommended booster and with food to maintain effective drug levels.
Report any rash, which should be assessed promptly as serious skin reactions can occur.
Do not start any new medicines, including over-the-counter products, without checking for interactions.

Evidence & guidelines

Boosted darunavir-based regimens are recommended in UK and international HIV treatment guidelines, supported by large randomised antiretroviral trials.

Reference: BHIVA HIV guidelines; EACS; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways