Prezista and Prezcobix
darunavir DRV Protease inhibitor and darunavir/cobicistat DRV/COBI
Standard DosePrezista: One 800 mg tablet plus 100 mg Norvir or 150 mg Tybost once daily with food for treatment-naïve people (those taking HIV therapy for the first time) and treatment-experienced adults without Prezista-related resistance. For adults and children 3 years of age and older weighing at least 22 pounds (10 kg). Prezista for children is dosed based on weight. There are 75 mg and 150 mg tablets as well as an oral suspension (100 mg/mL) (strawberry cream flavored) available for children age 3 and older and for adults who can’t swallow pills. One 600 mg tablet with 100 mg Norvir twice daily with food for pregnant individuals and for people who have at least one Prezista-related resistance mutation. Prezista should always be taken with Norvir or Tybost. Suspension needs to be taken with Norvir or Tybost, with food. Suspension should be shaken before each use and stored at room temperature. Do not refrigerate.
Prezcobix: One tablet (800 mg of darunavir boosted by 150 mg cobicistat) once daily with food, in people with no darunavir-associated drug resistance, including both treatment-experienced and treatment-naïve individuals. For adults and children weighing at least 88 pounds (40 kg). Prezcobix is only available for people taking darunavir once daily, not those who require darunavir twice daily. It is not recommended to co-administer Prezcobix with tenofovir disoproxil fumarate with creatinine clearance (CrCl) less than 70 mL/min.
Must also be taken in combination with another antiretroviral(s) that does not contain this medication or medication from the same drug classes. Do not use either drug in people with severe liver impairment. Take missed dose as soon as possible, unless it is closer to the time of your next dose. Do not double up on your next dose.
- See package insert for more complete information on potential side effects and interactions.
(800) JANSSEN (526-7736)
600 mg, 60 tablets: $2,338.22/month
800 mg, 30 tablets: $2,338.22/month
Potential Side Effects and Toxicity
Darunavir contains a sulfa component and should be used with caution by people with known sulfonamide allergy. Most common side effects may include diarrhea, nausea, headache, rash, vomiting, and abdominal pain. While very rare, severe rash can be accompanied by fever and/or elevations of liver enzymes, and can be life-threatening. Seek immediate medical attention. IRIS (immune reconstitution inflammatory syndrome) may occur as the immune system regains strength; signs and symptoms from previous infections may occur soon after HIV treatment is initiated. Report symptoms of illness, such as shingles or TB, to a health care provider. Protease inhibitors can cause increased risk for bleeding in hemophiliacs. Measure liver function before starting darunavir and then monitor, with perhaps closer monitoring for people with underlying liver problems, especially during the first several months. No dose adjustment necessary for Prezista with mild to moderate liver disease, but Prezista plus Norvir is not recommended for people with severe liver impairment. A small increase in serum creatinine (SCr) may be observed with Prezcobix that does not translate to a decrease in kidney function.
Potential Drug Interactions
Drug interactions of Prezista plus Norvir may be different from those with Prezista plus Tybost. Tybost is not interchangeable with Norvir. Do not take with alfuzosin, dronedarone, ergot derivatives, ivabradine, lomitapide, lurasidone, naloxegol, pimozide, triazolam, oral midazolam, ranolazine, rifampin, Revatio, St. John’s wort, or Zepatier. Do not use lovastatin or simvastatin, or co-formulations containing these drugs. Alternatives are atorvastatin and rosuvastatin (dose of either should not exceed 20 mg per day). Not recommended with avanafil, rifapentine, rivaroxaban, or salmeterol. Erectile dysfunction drugs should not exceed 10 mg Cialis or 2.5 mg Levitra per 72 hours, or 25 mg Viagra per 48 hours. Titration or decreased dose may be needed for buspirone, diazepam, estazolam, and zolpidem. Therapeutic drug monitoring is recommended for amiodarone, bepridil, disopyramide, flecainamide, systemic lidocaine, mexiletine, propafenone, and quinidine. Tell your provider or pharmacist about all medications, herbals, and supplements you are taking or thinking of taking, prescribed or not, as there are many other drug interactions not listed here.
Prezista: Not recommended with everolimus, or ticagrelor, or with irinotecan. Monitoring of clonazepam, phenytoin, and phenobarbital is recommended. Tramadol dose decrease may be needed. Monitor therapeutic effects and adverse reactions with use of some analgesics, such as fentanyl and oxycodone. Reducing dose of rifabutin is recommended. Pitavastatin may be used with no dose adjustment, but pravastatin should be used with caution and started at the lowest dose possible. Monitor for increased side effects from these medications. Reduce clarithromycin dose by 50–75% in kidney impairment. Isavuconazole, posaconazole, ketoconazole, and itraconazole should be used with caution (maximum dose is 200 mg per day for ketoconazole and itraconazole). Voriconazole should not be used unless the benefits outweigh the risks. Effectiveness of oral contraceptives may be decreased; consider using alternative methods of contraception. Increases the exposure of nasal and inhaled fluticasone and budesonide, as well as systemic corticosteroids ciclesonide, betamethasone, dexamethasone, methylprednisolone, mometasone, and triamcinolone. Use alternative corticosteroid and monitor for signs of Cushing’s syndrome. Beclomethasone, prednisolone, and prednisone as alternative corticosteroids may be considered, particularly for long-term use. Monitoring is recommended for co-administration with drospirenone due to the potential for hyperkalemia. Monitoring is recommended with buprenorphine, buprenorphine/naloxone, and methadone.
Prezcobix: Do not take with carbamazepine, dexamethasone, phenytoin, or phenobarbital, or with colchicine (in people with kidney or liver impairment). Not recommended to be taken with betamethasone, budesonide, ciclesonide, everolimus, fluticasone, Mavyret, methylprednisolone, mometasone, rifapentine, salmeterol, ticagrelor, triamcinolone, or voriconazole. Monitor for lack of virologic response when eslicarbazepine or oxcarbazepine is needed. Initiation or dose adjustments of insulin or oral hypoglycemic medications may be required for some individuals. Apixaban dose may need to be adjusted.
Pregnant individuals can voluntarily enroll in the Antiretroviral Pregnancy Registry through their provider; go to apregistry.com
Dr. Melanie Thompson:
Darunavir (Prezista) is the protease inhibitor backbone of Prezcobix as well as Symtuza. It has a high genetic barrier to resistance, meaning that a few missed doses are not likely to select for resistant viruses. But its Achilles heel is that it requires boosting with ritonavir or cobicistat. That is one of the key reasons that darunavir-based regimens are not recommended for initial therapy for most people with HIV. A large observational study found darunavir to be associated with higher cardiovascular risk than atazanavir. Cobicistat should not be given in pregnancy due to inadequate drug levels, so ritonavir should be used as a booster in this setting.
Activist Michael Broder:
Given other available options, it’s hard to imagine why any provider nowadays would recommend a boosted regimen.