Rezolsta is a fixed-dose tablet containing 800mg of darunavir and 150mg of cobicistat.
Darunavir is an HIV protease inhibitor. Cobicistat is used to boost blood levels of darunavir and has no antiviral activity of its own. Together, these drugs reduce the amount of HIV in the body and prevent the development of AIDS-defining illnesses.
Rezolsta received marketing approval in the European Union in November 2014. In the United States the fixed-dose tablet was approved with the brand name Prezcobix in January 2015.
Effectiveness
Rezolsta was approved based on data showing bioequivalence with darunavir boosted by ritonavir.
Rezolsta is not suitable for treatment-experienced patients with resistance to darunavir or with viral load above 100,000 copies/ml. Rezolsta is not suitable for people with advanced (decompensated) liver cirrhosis and should be used with caution in people with reduced kidney function (creatinine clearance < 70) when combined with tenofovir, emtricitabine or lamivudine.
Taking it
Rezolsta is dosed as one pink tablet to be taken once daily with food.
Side effects
The most common side effects of Rezolsta include:
- Headache, abnormal dreams, muscle pain, muscle cramps or weakness, osteonecrosis (death of bone tissue caused by loss of blood supply to the bone), diabetes and tiredness.
- Diarrhoea and nausea, vomiting, pain or swelling of the belly, indigestion, flatulence, decreased appetite.
- Allergic reactions such as rash, itching, swelling of the skin and other tissues (most often the lips or the eyes).
A common side effect of Rezolsta is the development of a rash. This is usually mild, but in rare cases it can be the sign of a more severe reaction.
Drug interactions
The use of cobicistat to boost blood levels of darunavir means that drug interactions with other medications are somewhat different from those reported for darunavir, due to the potential for interactions between both cobicistat and boosted darunavir and other medications.
Rezolsta should not be used in combination with non-nucleoside reverse transcriptase inhibitors (NNRTIs) with the exception of rilpivirine.
The following medicines should not be used in combination with Rezolsta:
- Carbamazepine, phenobarbital, phenytoin (anticonvulsants)
- Rifampicin
- St John's wort
- Alfuzosin
- Amiodarone, bepridil, dronedarone, quinidine, ranolazine, systemic lidocaine (antiarrhythmics/antianginals)
- Astemizole, terfenadine (antihistamines)
- Colchicine, when used in patients with renal and/or hepatic impairment (antigout)
- Ergot derivatives (e.g. dihydroergotamine, ergometrine, ergotamine, methylergonovine)
- Cisapride
- Pimozide, quetiapine, sertindole (antipsychotics/neuroleptics)
- Triazolam, midazolam administered orally
- Sildenafil and avanafil – when used for the treatment of pulmonary arterial hypertension (PDE-5 inhibitors)
- Simvastatin and lovastatin
- Ticagrelor (platelet aggregation inhibitor).
Pregnancy
Rezolsta is not recommended for use while pregnant or if planning to conceive owing to a risk of lower blood levels during pregnancy.
Children
Rezolsta is approved for use in children and adolescents aged 12 years and over weighing at least 40kg.
Further information
See darunavir for further details of efficacy and drug resistance.