Last Updated April 26, 2013
HIV protease inhibitor antiretroviral
50 mg/g oral powder
Indication: treatment of HIV infection in combination with other antiretrovirals.
Mechanism of action*: inhibits cleavage of viral gag-pol polyproteins precursors into functional proteins by binding to the HIV protease enzyme.
Pharmacokinetics*: metabolized in the liver by CYP 2C19 and 3A4 (metabolized to active M8 metabolite). Inhibits CYP 450 3A4 enzyme. Half-life: 3.5-5.0 hours.
Adult Dose: 750 mg three times daily or 1250 mg twice daily.
Use in Renal or Hepatic Insufficiency*:
Use in Pregnancy and Breastfeeding*: Category B. Excreted into breast milk.
Use in Children:
See Drug–Drug Interactions.
Contraindicated: amiodarone, quinidine, lovastatin, simvastatin, rifampicin, rifapentine, cisapride, pimozide, midazolam, triazolam, dihydroergotamine, ergonovine, ergotamine, methylergonovine, St John’s wort, alfuzosin, salmeterol, sildenafil for pulmonary arterial hypertension.
Increased concentrations of concomitant medication: warfarin, carbamazepine, tricyclic antidepressants, bosentan, azithromycin, clarithromycin, trazodone, rifabutin (dose rifabutin 150 mg once daily or 300 mg 3 times per week; monitor for antimycobacterial activity and consider therapeutic drug monitoring), alprazolam, diazepam, fluticasone, atorvastatin, rosuvastatin, lovastatin, simvastatin, sildenafil, tadalafil, vardenafil, colchicine, cyclosporine, tacrolimus, sirolimus.
Decreased concentrations of concomitant medication: methadone, warfarin, phenytoin, ethinyl estradiol, norethindrone.
See above for paediatric dosing.
Diarrhoea, hyperlipidemia, hyperglycaemia, fat maldistribution, potential for increased bleeding in patients with haemophilia, increased liver enzymes.
*Information from US prescribing information.