DARUNAVIR Drug Interactions: What You Need to Know

INTERACTIONS Co-administration of darunavir/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 darunavir/ritonavir to Affect Other Drugs Darunavir co-administered with ritonavir is an inhibitor of CYP3A, CYP2D6, and P-gp. Co-administration of darunavir 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. Darunavir 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 darunavir/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 darunavir/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 darunavir/ritonavir (which are administered with food). HIV-1-Antiviral Agents: HIV-Protease Inhibitors (PIs) indinavir (The reference regimen for indinavir was indinavir/ritonavir 800/100 mg twice daily.) lopinavir/ritonavir saquinavir Other HIV protease inhibitors, except atazanavir [see Drug Interactions (7.4)] ­  ­darunavir ­  indinavir ¯ darunavir « lopinavir ¯ darunavir « saquinavir The appropriate dose of indinavir in combination with darunavir/ritonavir has not been established. Appropriate doses of the combination have not been established. Hence, it is not recommended to co-administer lopinavir/ritonavir and darunavir, with or without ritonavir. Appropriate doses of the combination have not been established. Hence, it is not recommended to co-administer saquinavir and darunavir, with or without ritonavir. As co-administration with darunavir/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 darunavir/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 darunavir/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 rivaroxaban dabigatran etexilate edoxaban Other Anticoagulants warfarin ­  apixaban ­  rivaroxaban ­  dabigatran ­  edoxaban ↓ warfarin « darunavir Due to potentially increased bleeding risk, dosing recommendations for co-administration of apixaban with darunavir/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. Co-administration of darunavir/ritonavir and rivaroxaban is not recommended because it may lead to an increased bleeding risk. 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 darunavir/ritonavir. Warfarin concentrations are decreased when co-administered with darunavir/ritonavir. It is recommended that the international normalized ratio (INR) be monitored when warfarin is combined with darunavir/ritonavir. Anticonvulsants : carbamazepine « darunavir ­  carbamazepine The dose of either darunavir/ritonavir or carbamazepine does not need to be adjusted when initiating co-administration with darunavir/ritonavir and carbamazepine. Clinical monitoring of carbamazepine concentrations and its dose titration is recommended to achieve the desired clinical response. clonazepam phenobarbital, phenytoin ­  clonazepam « darunavir ↓ phenytoin ↓ phenobarbital Clinical monitoring of anticonvulsants that are metabolized by CYP3A is recommended. Phenytoin and phenobarbital levels should be monitored when co-administering with darunavir/ritonavir. Antidepressants : Selective Serotonin Reuptake Inhibitors (SSRIs): paroxetine, sertraline Tricyclic Antidepressants (TCAs): amitriptyline, desipramine, imipramine, nortriptyline Other: trazodone ↓ paroxetine ↓ sertraline ­  amitriptyline ­  desipramine ­  imipramine ­  nortriptyline ­  trazodone If either sertraline or paroxetine is initiated in patients receiving darunavir/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 darunavir/ritonavir. Use a lower dose of the tricyclic antidepressants and trazodone due to potential increased adverse events such as nausea, dizziness, hypotension and syncope. Antifungals : itraconazole, isavuconazole, ketoconazole, posaconazole voriconazole ­  darunavir ­  itraconazole ­  isavuconazole ­  ketoconazole « posaconazole ¯ voriconazole Monitor for increased darunavir/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 is not recommended for patients receiving darunavir/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 darunavir/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 darunavir/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 darunavir/ritonavir: maximum daily dose of 0.6 mg (may be given as 0.3 mg twice a day). Antimalarial : artemether/lumefantrine ¯ artemether ¯ dihydroartemisinin ­  lumefantrine « darunavir The combination of darunavir/ritonavir and artemether/lumefantrine can be used without dose adjustments. However, the combination should be used with caution as increased lumefantrine exposure may increase the risk of QT prolongation. Antimycobacterials : rifampin rifabutin (The reference regimen for rifabutin was 300 mg once daily.) rifapentine ↓ darunavir ­  darunavir ­  rifabutin ­ 25- O ­ desacetylrifabutin ¯ darunavir Co-administration is contraindicated due to potential for loss of therapeutic effect and development of resistance. Dose reduction of rifabutin by at least 75% of the usual dose (300 mg once daily) is recommended (i.e., a maximum dose of 150 mg every other day). Increased monitoring for adverse events is warranted in patients receiving this combination and further dose reduction of rifabutin may be necessary. Co-administration of darunavir/ritonavir with rifapentine is not recommended. Antineoplastics: dasatinib, nilotinib vinblastine, vincristine ­  antineoplastics A decrease in the dosage or an adjustment of the dosing interval of dasatinib and nilotinib may be necessary for patients. Please refer to the dasatinib and nilotinib prescribing information for dosing instructions. For vincristine and vinblastine, consideration should be given to temporarily withholding the ritonavir­containing antiretroviral regimen in patients who develop significant hematologic or gastrointestinal side effects when darunavir/ritonavir is administered concurrently with vincristine or vinblastine. If the antiretroviral regimen must be withheld for a prolonged period, consideration should be given to initiating a revised regimen that does not include a CYP3A or P-gp inhibitor. Antipsychotics : lurasidone pimozide quetiapine e.g. perphenazine, risperidone, thioridazine ­  lurasidone ­  pimozide ­  quetiapine ­  antipsychotics Co-administration is contraindicated due to potential for serious and/or life-threatening reactions. Co-administration is contraindicated due to potential for serious and/or life-threatening reactions such as cardiac arrhythmias. Initiation of darunavir with ritonavir in patients taking quetiapine: Consider alternative antiretroviral therapy to avoid increases in quetiapine exposures. If co-administration is necessary, reduce the quetiapine dose to 1/6 of the current dose and monitor for quetiapine-associated adverse reactions. Refer to the quetiapine prescribing information for recommendations on adverse reaction monitoring. Initiation of quetiapine in patients taking darunavir with ritonavir: Refer to the quetiapine prescribing information for initial dosing and titration of quetiapine. A decrease in the dose of antipsychotics that are metabolized by CYP3A or CYP2D6 may be needed when co-administered with darunavir/ritonavir. β-Blockers : e.g. carvedilol, metoprolol, timolol ­  beta-blockers Clinical monitoring of patients is recommended. A dose decrease may be needed for these drugs when co-administered with darunavir/ritonavir and a lower dose of the beta blocker should be considered.

Calcium Channel

Blockers : amlodipine, diltiazem, felodipine, nicardipine, nifedipine, verapamil ­  calcium channel blockers Clinical monitoring of patients is recommended.

Cardiac

Disorders : ranolazine, ivabradine dronedarone Other antiarrhythmics e.g. amiodarone, bepridil, disopyramide, flecainide, lidocaine (systemic), mexiletine, propafenone, quinidine digoxin ­  ranolazine ­  ivabradine ­  dronedarone ­  antiarrhythmics ­  digoxin Co-administration is contraindicated due to potential for serious and/or life-threatening reactions. Co-administration is contraindicated due to potential for serious and/or life-threatening reactions such as cardiac arrhythmias. Therapeutic concentration monitoring, if available, is recommended for antiarrhythmics when co-administered with darunavir/ritonavir. The lowest dose of digoxin should initially be prescribed. The serum digoxin concentrations should be monitored and used for titration of digoxin dose to obtain the desired clinical effect. Corticosteroids: dexamethasone (systemic) Corticosteroids primarily metabolized by CYP3A: eg. betamethasone budesonide ciclesonide fluticasone methylprednisolone mometasone triamcinolone ¯ darunavir ­  corticosteroids Co-administration of darunavir/ritonavir with systemic dexamethasone or other systemic corticosteroids that induce CYP3A may result in loss of therapeutic effect and development of resistance to darunavir. Consider alternative corticosteroids. Co-administration with corticosteroids (all routes of administration) of which exposures are significantly increased by strong CYP3A inhibitors can increase the risk for Cushing’s syndrome and adrenal suppression. Alternative corticosteroids including beclomethasone, prednisone, and prednisolone (for which PK and/or PD are less affected by strong CYP3A inhibitors relative to other steroids) should be considered, particularly for long term use. Endothelin receptor antagonist : bosentan ­ bosentan Co-administration of bosentan in patients on darunavir/ritonavir: In patients who have been receiving darunavir/ritonavir for at least 10 days, start bosentan at 62.5 mg once daily or every other day based upon individual tolerability. Co-administration of darunavir/ritonavir in patients on bosentan: Discontinue use of bosentan at least 36 hours prior to initiation of darunavir/ritonavir. After at least 10 days following the initiation of darunavir/ritonavir, resume bosentan at 62.5 mg once daily or every other day based upon individual tolerability. Ergot derivatives: e.g. dihydroergotamine, ergotamine, methylergonovine ­  ergot derivatives Co-administration is contraindicated due to potential for serious and/or life-threatening reactions such as acute ergot toxicity characterized by peripheral vasospasm and ischemia of the extremities and other tissues. Hepatitis C virus (HCV): Direct-Acting Antivirals: elbasvir/grazoprevir glecaprevir/pibrentasvir ­  elbasvir/grazoprevir ­  glecaprevir ­  pibrentasvir Co-administration is contraindicated due to potential for the increased risk of alanine transaminase (ALT) elevations. Co-administration of darunavir/ritonavir with glecaprevir/pibrentasvir is not recommended Herbal product: St. John’s wort ( Hypericum perforatum ) ¯ darunavir Co-administration is contraindicated due to potential for reduced plasma concentrations of darunavir, which may result in loss of therapeutic effect and development of resistance. Hormonal contraceptives : ethinyl estradiol, norethindrone, drospirenone ¯ ethinyl estradiol ¯ norethindrone drospirenone: effects unknown Effective alternative (non-hormonal) contraceptive method or a barrier method of contraception is recommended [see Use in Specific Populations (8.3)] . For co-administration with drospirenone, clinical monitoring is recommended due to the potential for hyperkalemia. No data are available to make recommendations on co-administration with other hormonal contraceptives. Immunosuppressants : e.g. cyclosporine, tacrolimus, sirolimus Immunosuppressant/neoplastic: everolimus irinotecan ­  immunosuppressants Therapeutic concentration monitoring of the immunosuppressive agent is recommended when co-administered with darunavir/ritonavir. Co-administration of everolimus and darunavir/ritonavir is not recommended. Discontinue darunavir/ritonavir at least 1 week prior to starting irinotecan therapy. Do not administer darunavir/ritonavir with irinotecan unless there are no therapeutic alternatives. Inhaled beta agonist : salmeterol ­  salmeterol Co-administration of salmeterol and darunavir/ritonavir is not recommended. The combination may result in increased risk of cardiovascular adverse events associated with salmeterol, including QT prolongation, palpitations and sinus tachycardia.

Lipid Modifying

Agents: HMG-CoA reductase inhibitors: lovastatin, simvastatin atorvastatin, pravastatin, rosuvastatin Other lipid modifying agent s: lomitapide ­  lovastatin ­  simvastatin ­  HMG-CoA reductase inhibitors ­  lomitapide Co-administration is contraindicated due to potential for serious reactions such as myopathy including rhabdomyolysis. Co-administration of darunavir/ritonavir with HMG-Co A reductase inhibitors may lead to adverse events such as myopathy. Titrate atorvastatin, pravastatin or rosuvastatin dose carefully and use the lowest necessary dose while monitoring for adverse events. Do not exceed atorvastatin 20 mg/day. Co-administration is contraindicated due to potential for markedly increased transaminases. Narcotic analgesics metabolized by CYP3A: e.g. fentanyl, oxycodone ­  fentanyl ­  oxycodone Careful monitoring of therapeutic effects and adverse reactions associated with CYP3A-metabolized narcotic analgesics (including potentially fatal respiratory depression) is recommended with co-administration. tramadol ­  tramadol A dose decrease may be needed for tramadol with concomitant use. Narcotic analgesics/treatment of opioid dependence : buprenorphine, buprenorphine/naloxone methadone « buprenorphine, naloxone ­  norbuprenorphine (metabolite) ¯ methadone No dose adjustment for buprenorphine or buprenorphine/naloxone is required with concurrent administration of darunavir/ritonavir. Clinical monitoring is recommended if darunavir/ritonavir and buprenorphine or buprenorphine/naloxone are co-administered. No adjustment of methadone dosage is required when initiating co-administration of darunavir/ritonavir. However, clinical monitoring is recommended as the dose of methadone during maintenance therapy may need to be adjusted in some patients.

Opioid

Antagonist naloxegol ­ naloxegol Co-administration of darunavir/ritonavir and naloxegol is contraindicated due to potential for precipitating opioid withdrawal symptoms. PDE-5 inhibitors : e.g. avanafil, sildenafil, tadalafil, vardenafil ­ PDE-5 inhibitors (only the use of sildenafil at doses used for treatment of erectile dysfunction has been studied with darunavir/ritonavir) Co-administration with darunavir/ritonavir may result in an increase in PDE-5 inhibitor-associated adverse events, including hypotension, syncope, visual disturbances and priapism. Use of PDE-5 inhibitors for pulmonary arterial hypertension (PAH): Co-administration with sildenafil used for PAH is contraindicated due to potential for sildenafil associated adverse reactions (which include visual disturbances, hypotension, prolonged erection, and syncope). The following dose adjustments are recommended for use of tadalafil with darunavir/ritonavir: Co-administration of tadalafil in patients on darunavir /ritonavir: In patients receiving darunavir/ritonavir for at least one week, start tadalafil at 20 mg once daily. Increase to 40 mg once daily based upon individual tolerability. Co-administration of darunavir/ritonavir in patients on tadalafil: Avoid use of tadalafil during the initiation of darunavir/ritonavir. Stop tadalafil at least 24 hours prior to starting darunavir/ritonavir. After at least one week following the initiation of darunavir/ritonavir, resume tadalafil at 20 mg once daily. Increase to 40 mg once daily based upon individual tolerability. Use of PDE-5 inhibitors for erectile dysfunction: Sildenafil at a single dose not exceeding 25 mg in 48 hours, vardenafil at a single dose not exceeding 2.5 mg dose in 72 hours, or tadalafil at a single dose not exceeding 10 mg dose in 72 hours can be used with increased monitoring for PDE-5 inhibitor-associated adverse events. Co-administration of darunavir/ritonavir and avanafil is not recommended. Platelet aggregation inhibitor: ticagrelor clopidogrel prasugrel ­  ticagrelor ↓clopidogrel active metabolite ↔ prasugrel active metabolite Co-administration of darunavir/ritonavir and ticagrelor is not recommended. Co-administration of darunavir/ritonavir and clopidogrel is not recommended due to potential reduction of the antiplatelet activity of clopidogrel. No dose adjustment is needed when prasugrel is co-administered with darunavir/ritonavir Proton pump inhibitor: omeprazole ¯ omeprazole « darunavir When omeprazole is co-administered with darunavir/ritonavir, monitor patients for decreased efficacy of omeprazole. Consider increasing the omeprazole dose in patients whose symptoms are not well controlled; avoid use of more than 40 mg per day of omeprazole. Sedatives/hypnotics: orally administered midazolam, triazolam metabolized by CYP3A e.g. buspirone, diazepam, estazolam, zolpidem parenterally administered midazolam ­  midazolam ­  triazolam ­  sedatives/hypnotics Co-administration is contraindicated due to potential for serious and/or life-threatening reactions such as prolonged or increased sedation or respiratory depression. Triazolam and orally administered midazolam are extensively metabolized by CYP3A. Co-administration of triazolam or orally administered midazolam with darunavir may cause large increases in the concentrations of these benzodiazepines. Titration is recommended when co-administering darunavir/ritonavir with sedatives/hypnotics metabolized by CYP3A and a lower dose of the sedatives/hypnotics should be considered with monitoring for adverse events. Co-administration of parenteral midazolam should be done in a setting which ensures close clinical monitoring and appropriate medical management in case of respiratory depression and/or prolonged sedation. Dosage reduction for midazolam should be considered, especially if more than a single dose of midazolam is administered. Urinary antispasmodics fesoterodine solifenacin ­  fesoterodine ­  solifenacin When fesoterodine is co-administered with darunavir/ritonavir, do not exceed a fesoterodine dose of 4 mg once daily. When solifenacin is co-administered with darunavir/ritonavir, do not exceed a solifenacin dose of 5 mg once daily.

7.4 Drugs without Clinically Significant Interactions with Darunavir No dosage adjustments are recommended when darunavir/ritonavir is co-administered with the following medications: atazanavir, dolutegravir, efavirenz, etravirine, nevirapine, nucleoside reverse transcriptase inhibitors (abacavir, emtricitabine, emtricitabine/tenofovir alafenamide, lamivudine, stavudine, tenofovir disoproxil fumarate, zidovudine), pitavastatin, raltegravir, ranitidine, or rilpivirine.

Co-administration of darunavir tablets/ritonavir is contraindicated with drugs that are highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events (narrow therapeutic index). Examples of these drugs and othercontraindicated drugs (which may lead to reduced efficacy of darunavir) are listed below [see Drug Interactions (7.3) ] . Due to the need for co-administration of darunavir tablets with ritonavir, please refer to ritonavir prescribing information for a description of ritonavir contraindications.

• Alpha 1-adrenoreceptor antagonist: alfuzosin
• Anti-gout: colchicine, in patients with renal and/or hepatic impairment
• Antimycobacterial: rifampin
• Antipsychotics: lurasidone, pimozide
• Cardiac Disorders: dronedarone, ivabradine, ranolazine
• Ergot derivatives, e.g. dihydroergotamine, ergotamine, methylergonovine
• Herbal product: St. John’s wort ( Hypericum perforatum )
• Hepatitis C direct acting antiviral: elbasvir/grazoprevir
• Lipid modifying agents: lomitapide, lovastatin, simvastatin
• Opioid Antagonist: naloxegol
• PDE-5 inhibitor: sildenafil when used for treatment of pulmonary arterial hypertension
• Sedatives/hypnotics: orally administered midazolam, triazolam
• Co-administration of darunavir tablets/ritonavir is contraindicated with drugs that are highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events (narrow therapeutic index). ( 4 )

AND PRECAUTIONS Drug-induced hepatitis (e.g., acute hepatitis, cytolytic hepatitis) has been reported with darunavir/ritonavir. Monitor liver function before and during therapy, especially in patients with underlying chronic hepatitis, cirrhosis, or in patients who have pre-treatment elevations of transaminases. Post-marketing cases of liver injury, including some fatalities, have been reported. ( 5.2 ) Skin reactions ranging from mild to severe, including Stevens-Johnson Syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms and acute generalized exanthematous pustulosis, have been reported. Discontinue treatment if severe reaction develops. ( 5.3 ) Use with caution in patients with a known sulfonamide allergy. ( 5.4 ) Patients may develop new onset diabetes mellitus or hyperglycemia. Initiation or dose adjustments of insulin or oral hypoglycemic agents may be required. ( 5.6 ) Patients may develop redistribution/accumulation of body fat or immune reconstitution syndrome. ( 5.7 , 5.8 ) Patients with hemophilia may develop increased bleeding events. ( 5.9 ) Darunavir/ritonavir is not recommended in pediatric patients below 3 years of age in view of toxicity and mortality observed in juvenile rats dosed with darunavir up to days 23 to 26 of age. ( 5.10 )

5.1 Importance of Co-administration with Ritonavir Darunavir tablets must be co-administered with ritonavir and food to achieve the desired antiviral effect. Failure to administer darunavir tablets with ritonavir and food may result in a loss of efficacy of darunavir. Please refer to ritonavir prescribing information for additional information on precautionary measures.

5.2 Hepatotoxicity Drug-induced hepatitis (e.g., acute hepatitis, cytolytic hepatitis) has been reported with darunavir/ritonavir. During the clinical development program (N=3063), hepatitis was reported in 0.5% of patients receiving combination therapy with darunavir/ritonavir. Patients with pre-existing liver dysfunction, including chronic active hepatitis B or C, have an increased risk for liver function abnormalities including severe hepatic adverse events. Post-marketing cases of liver injury, including some fatalities, have been reported. These have generally occurred in patients with advanced HIV-1 disease taking multiple concomitant medications, having co-morbidities including hepatitis B or C co-infection, and/or developing immune reconstitution syndrome. A causal relationship with darunavir/ritonavir therapy has not been established. Appropriate laboratory testing should be conducted prior to initiating therapy with darunavir/ritonavir and patients should be monitored during treatment. Increased AST/ALT monitoring should be considered in patients with underlying chronic hepatitis, cirrhosis, or in patients who have pre-treatment elevations of transaminases, especially during the first several months of darunavir/ritonavir treatment. Evidence of new or worsening liver dysfunction (including clinically significant elevation of liver enzymes and/or symptoms such as fatigue, anorexia, nausea, jaundice, dark urine, liver tenderness, hepatomegaly) in patients on darunavir/ritonavir should prompt consideration of interruption or discontinuation of treatment.

5.3 Severe Skin Reactions During the clinical development program (n=3063), severe skin reactions, accompanied by fever and/or elevations of transaminases in some cases, have been reported in 0.4% of subjects. Stevens-Johnson Syndrome was rarely (less than 0.1%) reported during the clinical development program. During post-marketing experience toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms, and acute generalized exanthematous pustulosis have been reported. Discontinue darunavir/ritonavir immediately if signs or symptoms of severe skin reactions develop. These can include but are not limited to severe rash or rash accompanied with fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, conjunctivitis, hepatitis and/or eosinophilia. Rash (all grades, regardless of causality) occurred in 10.3% of subjects treated with darunavir/ritonavir <span class="opacity-50 text-xs">[see Adverse Reactions ( 6 )]</span> . Rash was mostly mild-to-moderate, often occurring within the first four weeks of treatment and resolving with continued dosing. The discontinuation rate due to rash in subjects using darunavir/ritonavir was 0.5%. Rash occurred more commonly in treatment-experienced subjects receiving regimens containing darunavir/ritonavir + raltegravir compared to subjects receiving darunavir/ritonavir without raltegravir or raltegravir without darunavir/ritonavir. However, rash that was considered drug related occurred at similar rates for all three groups. These rashes were mild to moderate in severity and did not limit therapy; there were no discontinuations due to rash.

5.4 Sulfa Allergy Darunavir contains a sulfonamide moiety. Darunavir tablets should be used with caution in patients with a known sulfonamide allergy. In clinical studies with darunavir/ritonavir, the incidence and severity of rash were similar in subjects with or without a history of sulfonamide allergy.

5.5 Risk of Serious Adverse Reactions due to Drug Interactions Initiation of darunavir/ritonavir, a CYP3A inhibitor, in patients receiving medications metabolized by CYP3A or initiation of medications metabolized by CYP3A in patients already receiving darunavir/ritonavir, may increase plasma concentrations of medications metabolized by CYP3A and reduce plasma concentrations of active metabolite(s) formed by CYP3A. Initiation of medications that inhibit or induce CYP3A may increase or decrease concentrations of darunavir/ritonavir, respectively. These interactions may lead to: Clinically significant adverse reactions, potentially leading to severe, life threatening, or fatal events from greater exposures of concomitant medications. Clinically significant adverse reactions from greater exposures of darunavir/ritonavir. Loss of therapeutic effect of the concomitant medications from lower exposures of active metabolite(s). Loss of therapeutic effect of darunavir/ritonavir and possible development of resistance from lower exposures of darunavir/ritonavir.

See Table

10 for steps to prevent or manage these possible and known significant drug interactions, including dosing recommendations [ see Drug Interactions ( 7 )] . Consider the potential for drug interactions prior to and during darunavir/ritonavir therapy; review concomitant medications during darunavir/ritonavir therapy; and monitor for the adverse reactions associated with the concomitant drugs [ see Contraindications ( 4 ) and Drug Interactions ( 7 )] .

5.6 Diabetes Mellitus/Hyperglycemia New onset diabetes mellitus, exacerbation of pre-existing diabetes mellitus, and hyperglycemia have been reported during postmarketing surveillance in HIV-infected patients receiving protease inhibitor (PI) therapy. Some patients required either initiation or dose adjustments of insulin or oral hypoglycemic agents for treatment of these events. In some cases, diabetic ketoacidosis has occurred. In those patients who discontinued PI therapy, hyperglycemia persisted in some cases. Because these events have been reported voluntarily during clinical practice, estimates of frequency cannot be made and causal relationships between PI therapy and these events have not been established.

5.7 Fat Redistribution Redistribution/accumulation of body fat, including central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting, facial wasting, breast enlargement, and &quot;cushingoid appearance&quot; have been observed in patients receiving antiretroviral therapy. The mechanism and long-term consequences of these events are currently unknown. A causal relationship has not been established.

5.8 Immune Reconstitution Syndrome Immune reconstitution syndrome has been reported in patients treated with combination antiretroviral therapy, including darunavir. During the initial phase of combination antiretroviral treatment, patients whose immune systems respond may develop an inflammatory response to indolent or residual opportunistic infections (such as Mycobacterium avium infection, cytomegalovirus, Pneumocystis jirovecii pneumonia [PCP], or tuberculosis), which may necessitate further evaluation and treatment. Autoimmune disorders (such as Graves&apos; disease, polymyositis, and Guillain-Barr¡SR syndrome and autoimmune hepatitis) have also been reported to occur in the setting of immune reconstitution; however, the time to onset is more variable, and can occur many months after initiation of antiretroviral treatment.

5.9 Hemophilia There have been reports of increased bleeding, including spontaneous skin hematomas and hemarthrosis in patients with hemophilia type A and B treated with PIs. In some patients, additional factor VIII was given. In more than half of the reported cases, treatment with PIs was continued or reintroduced if treatment had been discontinued. A causal relationship between PI therapy and these episodes has not been established.

5.10 Not Recommended in Pediatric Patients Below 3 Years of Age Darunavir/ritonavir in pediatric patients below 3 years of age is not recommended in view of toxicity and mortality observed in juvenile rats dosed with darunavir (from 20 mg/kg to 1000 mg/kg) up to days 23 to 26 of age <span class="opacity-50 text-xs">[see Use in Specific Populations ( 8.1 and 8.4 ) and Clinical Pharmacology ( 12.3 )]</span> .