Darunavir

Co-administration of PREZISTA/ritonavir with other drugs can alter the concentrations of other drugs and other drugs may alter the concentrations of darunavir. The potential drug-drug interactions must be considered prior to and during therapy. ( 4 , 5.5 , 7 , 12.3 )

7.1 Potential for PREZISTA/ritonavir to Affect Other Drugs PREZISTA co-administered with ritonavir is an inhibitor of CYP3A, CYP2D6, and P-gp. Co-administration of PREZISTA and ritonavir with drugs that are primarily metabolized by CYP3A and CYP2D6 or are transported by P-gp may result in increased plasma concentrations of such drugs, which could increase or prolong their therapeutic effect and adverse events. PREZISTA co-administered with ritonavir with drugs that have active metabolite(s) formed by CYP3A may result in reduced plasma concentrations of these active metabolite(s), potentially leading to loss of their therapeutic effect (see Table 10 ).

7.2 Potential for Other Drugs to Affect Darunavir Darunavir and ritonavir are metabolized by CYP3A. In vitro data indicate that darunavir may be a P-gp substrate. Drugs that induce CYP3A activity would be expected to increase the clearance of darunavir and ritonavir, resulting in lowered plasma concentrations of darunavir and ritonavir. Co-administration of darunavir and ritonavir and other drugs that inhibit CYP3A, or P-gp may decrease the clearance of darunavir and ritonavir and may result in increased plasma concentrations of darunavir and ritonavir (see Table 10 ).

7.3 Established and Other Potentially Significant Drug Interactions Table 10 provides dosing recommendations as a result of drug interactions with PREZISTA/ritonavir. These recommendations are based on either drug interaction studies or predicted interactions due to the expected magnitude of interaction and potential for serious adverse events or loss of efficacy.

The table includes examples of potentially significant interactions but is not all inclusive [see Contraindications (4) and Clinical Pharmacology (12.3) ] , and therefore the label of each drug that is co-administered with PREZISTA/ritonavir should be consulted for information related to the route of metabolism, interaction pathways, potential risks, and specific actions to be taken with regard to co-administration.

Table 10: Established and Other Potentially Significant Drug Interactions: Alterations in Dose or Regimen May be Recommended Based on Drug Interaction Studies or Predicted Interaction (see Contraindications (4) for a list of examples of contraindicated drugs) [see Clinical Pharmacology (12.3) for Magnitude of Interaction, Tables 15 and 16 ] Concomitant Drug Class Drug Name Examples Effect on Concentration of Darunavir Or Concomitant Drug Clinical Comment HIV-1-Antiviral Agents: Nucleoside Reverse Transcriptase Inhibitors (NRTIs) didanosine ↔ darunavir ↔ didanosine Didanosine should be administered one hour before or two hours after PREZISTA/ritonavir (which are administered with food).

HIV-1-Antiviral Agents: HIV-Protease Inhibitors (PIs) indinavir ↑ darunavir ↑ indinavir The appropriate dose of indinavir in combination with PREZISTA/ritonavir has not been established. (The reference regimen for indinavir was indinavir/ritonavir 800/100 mg twice daily.) lopinavir/ritonavir ↓ darunavir ↔ lopinavir Appropriate doses of the combination have not been established. Hence, it is not recommended to co-administer lopinavir/ritonavir and PREZISTA, with or without ritonavir. saquinavir ↓ darunavir ↔ saquinavir Appropriate doses of the combination have not been established. Hence, it is not recommended to co-administer saquinavir and PREZISTA, with or without ritonavir.

Other HIV protease inhibitors, except atazanavir [see Drug Interactions (7.4) ] As co-administration with PREZISTA/ritonavir has not been studied, co-administration is not recommended. HIV-1-Antiviral Agents: CCR5 co-receptor antagonists maraviroc ↑ maraviroc When used in combination with PREZISTA/ritonavir, the dose of maraviroc should be 150 mg twice daily. Other Agents Alpha 1-adrenoreceptor antagonist: alfuzosin ↑ alfuzosin Co-administration is contraindicated due to potential for serious and/or life-threatening reactions such as hypotension.

Antibacterial : clarithromycin ↔ darunavir ↑ clarithromycin No dose adjustment of the combination is required for patients with normal renal function. For co-administration of clarithromycin and PREZISTA/ritonavir in patients with renal impairment, the following dose adjustments should be considered: For subjects with CLcr of 30–60 mL/min, the dose of clarithromycin should be reduced by 50%. For subjects with CLcr of <30 mL/min, the dose of clarithromycin should be reduced by 75%.

Anticoagulants : Direct Oral Anticoagulants (DOACs) apixaban ↑ apixaban Due to potentially increased bleeding risk, dosing recommendations for co-administration of apixaban with PREZISTA/ritonavir depend on the apixaban dose. Refer to apixaban dosing instructions for co-administration with P-gp and strong CYP3A inhibitors in apixaban prescribing information. rivaroxaban ↑ rivaroxaban Co-administration of PREZISTA/ritonavir and rivaroxaban is not recommended because it may lead to an increased bleeding risk. dabigatran etexilate edoxaban ↑ dabigatran ↑ edoxaban Refer to the dabigatran etexilate or edoxaban prescribing information for recommendations regarding co-administration.

The specific recommendations are based on indication, renal function, and effect of the co-administered P-gp inhibitors on the concentration of dabigatran or edoxaban. Clinical monitoring is recommended when a DOAC not affected by CYP3A4 but transported by P-gp, including dabigatran etexilate and edoxaban, is co-administered with PREZISTA/ritonavir. Other Anticoagulants warfarin ↓ warfarin ↔ darunavir Warfarin concentrations are decreased when co-administered with PREZISTA/ritonavir. It is recommended that the international normalized ratio (INR) be monitored when warfarin is combined with PREZISTA/ritonavir.

Anticonvulsants : carbamazepine ↔ darunavir ↑ carbamazepine The dose of either PREZISTA/ritonavir or carbamazepine does not need to be adjusted when initiating co-administration with PREZISTA/ritonavir and carbamazepine. Clinical monitoring of carbamazepine concentrations and its dose titration is recommended to achieve the desired clinical response. clonazepam ↑ clonazepam Clinical monitoring of anticonvulsants that are metabolized by CYP3A is recommended. phenobarbital, phenytoin ↔ darunavir ↓ phenytoin ↓ phenobarbital Phenytoin and phenobarbital levels should be monitored when co-administering with PREZISTA/ritonavir.

Antidepressants : Selective Serotonin Reuptake Inhibitors (SSRIs): paroxetine, sertraline ↓ paroxetine ↓ sertraline If either sertraline or paroxetine is initiated in patients receiving PREZISTA/ritonavir, dose titrating the SSRI based on a clinical assessment of antidepressant response is recommended. Monitor for antidepressant response in patients on a stable dose of sertraline or paroxetine who start treatment with PREZISTA/ritonavir.

Tricyclic Antidepressants (TCAs): amitriptyline, desipramine, imipramine, nortriptyline ↑ amitriptyline ↑ desipramine ↑ imipramine ↑ nortriptyline Use a lower dose of the tricyclic antidepressants and trazodone due to potential increased adverse events such as nausea, dizziness, hypotension and syncope. Other: trazodone ↑ trazodone Antifungals : itraconazole, isavuconazole, ketoconazole, posaconazole ↑ darunavir ↑ itraconazole ↑ isavuconazole ↑ ketoconazole ↔ posaconazole Monitor for increased PREZISTA/ritonavir and/or antifungal adverse events with concomitant use of these antifungals.

When co-administration is required, the daily dose of ketoconazole or itraconazole should not exceed 200 mg with monitoring for increased antifungal adverse events. voriconazole ↓ voriconazole Voriconazole is not recommended for patients receiving PREZISTA/ritonavir unless an assessment comparing predicted benefit to risk ratio justifies the use of voriconazole. Anti-gout : colchicine ↑ colchicine Co-administration is contraindicated in patients with renal and/or hepatic impairment due to potential for serious and/or life-threatening reactions.

For patients without renal or hepatic impairment: Treatment of gout-flares – co-administration of colchicine in patients on PREZISTA/ritonavir: 0.6 mg (1 tablet) × 1 dose, followed by 0.3 mg (half tablet) 1 hour later. Treatment course to be repeated no earlier than 3 days. Prophylaxis of gout-flares – co-administration of colchicine in patients on PREZISTA/ritonavir: If the original regimen was 0.6 mg twice a day, the regimen should be adjusted to 0.3 mg once a day. If the original regimen was 0.6 mg once a day, the regimen should be adjusted to 0.3 mg once every other day.

Treatment of familial Mediterranean fever – co-administration of colchicine in patients on PREZISTA/ritonavir: maximum daily dose of 0.6 mg (may be given as 0.3 mg twice a day).…

8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to PREZISTA during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) 1-800-258-4263. Risk Summary Prospective pregnancy data from the APR are not sufficient to adequately assess the risk of birth defects or miscarriage. Available limited data from the APR show no statistically significant difference in the overall risk of major birth defects for darunavir compared with the background rate for major birth defects of 2.7% in a U.S.

reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP ) [see Data ] . The rate of miscarriage is not reported in the APR. The estimated background rate of miscarriage in clinically recognized pregnancies in the U.S. general population is 15-20%. The background risk of major birth defects and miscarriage for the indicated population is unknown. Studies in animals did not show evidence of developmental toxicity. Exposures (based on AUC) in rats were 3-fold higher, whereas in mice and rabbits, exposures were lower (less than 1-fold) than human exposures at the recommended daily dose [see Data ] .

Clinical Considerations The recommended dosage in pregnant patients is PREZISTA 600 mg taken with ritonavir 100 mg twice daily with food. PREZISTA 800 mg taken with ritonavir 100 mg once daily should only be considered in certain pregnant patients who are already on a stable PREZISTA 800 mg with ritonavir 100 mg once daily regimen prior to pregnancy, are virologically suppressed (HIV-1 RNA less than 50 copies per mL), and in whom a change to twice daily PREZISTA 600 mg with ritonavir 100 mg may compromise tolerability or compliance [see Dosage and Administration (2.4) and Clinical Pharmacology (12.3) ] .

Data Human Data PREZISTA/ritonavir (600/100 mg twice daily or 800/100 mg once daily) in combination with a background regimen was evaluated in a clinical trial of 36 pregnant women during the second and third trimesters, and postpartum. Eighteen subjects were enrolled in each BID and QD treatment arms. Twenty-nine subjects completed the trial through the postpartum period (6–12 weeks after delivery) and 7 subjects discontinued before trial completion, 5 subjects in the BID arm and 2 subjects in the QD arm. The pharmacokinetic data demonstrate that exposure to darunavir and ritonavir as part of an antiretroviral regimen was lower during pregnancy compared with postpartum (6–12 weeks).

Exposure reductions during…