TIPRANAVIR Drug Interactions: What You Need to Know

INTERACTIONS Co-administration of APTIVUS can alter the concentrations of other drugs and other drugs may alter the concentration of tipranavir. The potential for drug-drug interactions must be considered prior to and during therapy. ( 4 , 5.4 , 7 )

7.1 Potential for APTIVUS/ritonavir to Affect Other Drugs APTIVUS co-administered with ritonavir at the recommended dose is a net inhibitor of CYP3A and may increase plasma concentrations of agents that are primarily metabolized by CYP3A. Thus, co-administration of APTIVUS/ritonavir with drugs highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events is contraindicated <span class="opacity-50 text-xs">[see Contraindications (4) ]</span> . Co-administration with other CYP3A substrates may require a dose adjustment or additional monitoring <span class="opacity-50 text-xs">[see Drug Interactions (7) ]</span> . Clinically significant drug-drug interactions of APTIVUS co-administered with ritonavir are summarized in Table 4 below. A phenotypic cocktail study was conducted with 16 healthy volunteers to quantify the influence of 10 days of APTIVUS/ritonavir capsule administration on the activity of hepatic CYP1A2 (caffeine), 2C9 (warfarin), 2C19 (omeprazole), 2D6 (dextromethorphan) and the activity of intestinal and hepatic CYP3A4/5 (midazolam) and P-glycoprotein (P-gp) (digoxin). This study determined the first-dose and steady-state effects of 500 mg of APTIVUS co-administered with 200 mg of ritonavir twice daily in capsule form. There was no net effect on CYP2C9 or hepatic P-gp at first dose or steady state. There was no net effect after first dose on CYP1A2, but there was moderate induction at steady state. There was modest inhibition of CYP2C19 at the first dose, but there was marked induction at steady state. Potent inhibition of CYP2D6 and both hepatic and intestinal CYP3A4/5 activities were observed after first dose and steady state. Intestinal and hepatic P-gp activity was assessed by administering oral and intravenous digoxin, respectively. The digoxin results indicate P-gp was inhibited after the first dose of APTIVUS/ritonavir followed by induction of P-gp over time. Thus, it is difficult to predict the net effect of APTIVUS administered with ritonavir on oral bioavailability and plasma concentrations of drugs that are dual substrates of CYP3A and P-gp. The net effect will vary depending on the relative affinity of the co-administered drugs for CYP3A and P-gp, and the extent of intestinal first-pass metabolism/efflux. An in vitro induction study in human hepatocytes showed an increase in UGT1A1 by tipranavir similar to that evoked by rifampin. The clinical consequences of this finding have not been established.

7.2 Potential for Other Drugs to Affect Tipranavir Tipranavir is a CYP3A substrate and a P-gp substrate. Co-administration of APTIVUS/ritonavir and drugs that induce CYP3A and/or P-gp may decrease tipranavir plasma concentrations. Co-administration of APTIVUS/ritonavir and drugs that inhibit P-gp may increase tipranavir plasma concentrations. Co-administration of APTIVUS/ritonavir with drugs that inhibit CYP3A may not further increase tipranavir plasma concentrations, because the level of metabolites is low following steady-state administration of APTIVUS/ritonavir 500 mg/200 mg twice daily. Clinically significant drug-drug interactions of APTIVUS co-administered with ritonavir are summarized in Table 4 below <span class="opacity-50 text-xs">[see Contraindications (4) , Warnings and Precautions (5.4) , and Clinical Pharmacology (12.3) ]</span> .

Table

4 Established and Other Potentially Significant Drug Interactions: Alterations in Dose or Regimen May be Recommended Based on Drug Interaction Studies or Predicted Interaction Concomitant Drug Class: Drug name Effect on Concentration of Tipranavir or Concomitant Drug Clinical Comment ↑ increase, ↓ decrease, ↔ no change, ↕ unable to predict HIV-1 Antiviral Agents Fusion Inhibitors: Enfuvirtide ↑ Tipranavir At steady state, tipranavir trough concentrations were approximately 45% higher in patients co-administered enfuvirtide in the Phase 3 trials. The mechanism for this increase is not known. Dose adjustments are not recommended. Non-Nucleoside Reverse Transcriptase Inhibitors: Etravirine ↓ Etravirine APTIVUS/ritonavir when coadministered with etravirine may cause a significant decrease in the plasma concentrations of etravirine and loss of therapeutic effect of etravirine. Etravirine and APTIVUS/ritonavir should not be coadministered.

Rilpivirine

The use of rilpivirine co-administered with APTIVUS/ritonavir has not been studied. Concomitant use of rilpivirine with Aptivus/ritonavir may cause an increase in the plasma concentrations of rilpivirine (inhibition of CYP3A enzymes). Rilpivirine is not expected to affect the plasma concentrations of Aptivus/ritonavir.

Nucleoside Reverse Transcriptase

Inhibitors: Abacavir ↓ Abacavir AUC by approximately 40% Clinical relevance of reduction in abacavir levels not established. Dose adjustment of abacavir cannot be recommended at this time. Didanosine (EC) ↓ Didanosine Clinical relevance of reduction in didanosine levels not established. For optimal absorption, didanosine should be separated from APTIVUS/ritonavir dosing by at least 2 hours. Zidovudine ↓ Zidovudine AUC by approximately 35%. ZDV glucuronide concentrations were unaltered. Clinical relevance of reduction in zidovudine levels not established. Dose adjustment of zidovudine cannot be recommended at this time.

Protease

Inhibitors (co-administered with 200 mg of ritonavir): Fosamprenavir ↓ Amprenavir Combining a protease inhibitor with APTIVUS/ritonavir is not recommended. Lopinavir ↓ Lopinavir Saquinavir ↓ Saquinavir Protease Inhibitors (co-administered with 100 mg of ritonavir): Atazanavir ↓ Atazanavir ↑ Tipranavir Virus Integrase Strand Transfer Inhibitors (INSTI): Raltegravir ↓ Raltegravir No dose adjustment is needed for 400 mg twice daily dosing regimen of raltegravir. For all other dosing regimens of raltegravir, refer to current prescribing information for raltegravir. Dolutegravir ↓ Dolutegravir For dosage recommendations, refer to dolutegravir prescribing information. Agents for Opportunistic Infections Antifungals: Fluconazole Itraconazole Ketoconazole ↑ Tipranavir, ↔ Fluconazole Fluconazole increases tipranavir concentrations but dose adjustments are not needed. Fluconazole doses >200 mg/day are not recommended. Voriconazole ↑ Itraconazole (not studied) ↑ Ketoconazole (not studied) Based on theoretical considerations itraconazole and ketoconazole should be used with caution. High doses (>200 mg/day) are not recommended. ↕ Voriconazole (not studied) Due to multiple enzymes involved with voriconazole metabolism, it is difficult to predict the interaction. Antimycobacterials: Clarithromycin ↑ Tipranavir, ↑ Clarithromycin, ↓ 14-hydroxy-clarithromycin metabolite No dose adjustment of APTIVUS or clarithromycin for patients with normal renal function is necessary. For patients with renal impairment the following dosage adjustments should be considered: For patients with CL CR 30 to 60 mL/min the dose of clarithromycin should be reduced by 50%. For patients with CL CR <30 mL/min the dose of clarithromycin should be decreased by 75%.

Rifabutin

Tipranavir not changed, ↑Rifabutin ↑ Desacetyl-rifabutin Single dose study. Dosage reductions of rifabutin by 75% are recommended (e.g., 150 mg every other day). Increased monitoring for adverse events in patients receiving the combination is warranted. Further dosage reduction may be necessary.

Other Agents Commonly Used

Anticonvulsants: Carbamazepine Phenobarbital Phenytoin ↓ Tipranavir Caution should be used when prescribing carbamazepine, phenobarbital and/or phenytoin. APTIVUS may be less effective due to decreased tipranavir plasma concentration in patients taking these agents concomitantly.

Valproic

Acid ↓ Valproic Acid Caution should be used when prescribing valproic acid. Valproic acid may be less effective due to decreased valproic acid plasma concentration in patients taking APTIVUS concomitantly. Antidepressants: Trazodone ↑ Trazodone Concomitant use of trazodone and APTIVUS/ritonavir may increase plasma concentrations of trazodone. Adverse events of nausea, dizziness, hypotension, and syncope have been observed following co-administration of trazodone and ritonavir. If trazodone is used with a CYP3A4 inhibitor such as APTIVUS/ritonavir, the combination should be used with caution and a lower dose of trazodone should be considered.

Desipramine

Combination with APTIVUS/ritonavir not studied ↑ Desipramine Dosage reduction and concentration monitoring of desipramine is recommended.

Selective

Serotonin-Reuptake Inhibitors: Combination with APTIVUS/ritonavir not studied Antidepressants have a wide therapeutic index, but doses may need to be adjusted upon initiation of APTIVUS/ritonavir therapy.

Fluoxetine Paroxetine

Sertraline ↑ Fluoxetine ↑ Paroxetine ↑ Sertraline Anti-gout Colchicine ↑ Colchicine In patients with renal or hepatic impairment, co-administration of colchicine in patients on APTIVUS/ritonavir is contraindicated. In combination with APTIVUS/ritonavir, the following dosage adjustments are recommended in patients with normal renal and hepatic function: Treatment of gout flares: Co-administration of colchicine in patients on APTIVUS/ritonavir: 0.6 mg (1 tablet) × 1 dose, followed by 0.3 mg (half tablet) 1 hour later. Dose to be repeated no earlier than 3 days. Prophylaxis of gout flares: Co-administration of colchicine in patients on APTIVUS/ritonavir : If the original colchicine regimen was 0.6 mg twice a day, the regimen should be adjusted to 0.3 mg once a day. If the original colchicine 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 (FMF): Co-administration of colchicine in patients on APTIVUS/ritonavir: Maximum daily dose of 0.6 mg (may be given as 0.3 mg twice a day). Antipsychotics: Quetiapine ↑ Quetiapine Initiation of APTIVUS 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 APTIVUS with ritonavir: Refer to the quetiapine prescribing information for initial dosing and titration of quetiapine. Benzodiazepines: Parenterally administered midazolam ↑ Midazolam Midazolam is extensively metabolized by CYP3A4. Increases in the concentration of midazolam are expected to be significantly higher with oral than parenteral administration. Therefore, APTIVUS should not be given with orally administered midazolam [ see Contraindications (4) ]. If APTIVUS is co-administered with parenteral midazolam, close clinical monitoring for respiratory depression and/or prolonged sedation should be exercised and dosage adjustments should be considered. Buprenorphine/naloxone ↔ Buprenorphine ↓ Tipranavir APTIVUS/ritonavir did not result in changes in the clinical efficacy of buprenorphine/naloxone. Compared to historical controls tipranavir C min was decreased approximately 40% with this combination. Dose adjustments cannot be recommended.

Calcium Channel

Blockers: Combination with APTIVUS/ritonavir not studied. Cannot predict effect of TPV/ritonavir on calcium channel blockers that are dual substrates of CYP3A and P-gp due to conflicting effect of TPV/ritonavir on CYP3A and P-gp. Caution is warranted and clinical monitoring of patients is recommended.

Diltiazem Felodipine Nicardipine Nisoldipine

Verapamil ↕ Diltiazem ↑ Felodipine (CYP3A substrate but not P-gp substrate) ↕ Nicardipine ↕ Nisoldipine (CYP3A substrate but not clear whether it is a P-gp substrate) ↕ Verapamil Disulfiram/Metronidazole Combination with TPV/ritonavir not studied APTIVUS capsules contain alcohol that can produce disulfiram-like reactions when co-administered with disulfiram or other drugs which produce this reaction (e.g., metronidazole). Endothelin receptor antagonists Co-administration of bosentan in patients on APTIVUS/ritonavir: Bosentan ↑ Bosentan In patients who have been receiving APTIVUS/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 APTIVUS/ritonavir in patients on bosentan: Discontinue use of bosentan at least 36 hours prior to initiation of APTIVUS/ritonavir. After at least 10 days following the initiation of APTIVUS/ritonavir, resume bosentan at 62.5 mg once daily or every other day based upon individual tolerability. HMG-CoA Reductase Inhibitors: Atorvastatin Rosuvastatin ↑ Atorvastatin ↓ Hydroxy-atorvastatin metabolites ↑ Rosuvastatin Avoid co-administration with atorvastatin. Hypoglycemics: Combination with APTIVUS/ritonavir not studied Careful glucose monitoring is warranted.

Glimepiride Glipizide Glyburide Pioglitazone Repaglinide

Tolbutamide ↔ Glimepiride (CYP2C9) ↔ Glipizide (CYP2C9) ↔ Glyburide (CYP2C9) ↕ Pioglitazone (CYP2C8 and CYP3A4) ↕ Repaglinide (CYP2C8 and CYP3A4) ↔ Tolbutamide (CYP2C9) The effect of TPV/ritonavir on CYP2C8 substrate is not known. Immunosuppressants: Combination with APTIVUS/ritonavir not studied. Cannot predict effect of TPV/ritonavir on immunosuppressants due to conflicting effect of TPV/ritonavir on CYP3A and P-gp. Increased frequency of monitoring of plasma levels of immunosuppressant drugs is recommended.

Cyclosporine Sirolimus

Tacrolimus ↕ Cyclosporine ↕ Sirolimus ↕ Tacrolimus Inhaled beta agonist: Concurrent administration of APTIVUS/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. Salmeterol ↑ Salmeterol Inhaled/Nasal Steroids: Fluticasone ↑ Fluticasone Concomitant use of fluticasone propionate and APTIVUS/ritonavir may increase plasma concentrations of fluticasone propionate, resulting in significantly reduced serum cortisol concentrations. Co-administration of fluticasone propionate and APTIVUS/ritonavir is not recommended unless the potential benefit to the patient outweighs the risk of systemic corticosteroid side effects.

Narcotic

Analgesics: Combinations with APTIVUS/ritonavir not studied Dosage increase and long-term use of meperidine are not recommended due to increased concentrations of the metabolite normeperidine which has both analgesic activity and CNS stimulant activity (e.g., seizures). Meperidine ↓ Meperidine, ↑ Normeperidine Methadone ↓ Methadone Dosage of methadone may need to be increased when co-administered with APTIVUS and 200 mg of ritonavir. ↓ S-Methadone, ↓ R-Methadone Oral Contraceptives/Estrogens: Ethinyl estradiol ↓ Ethinyl estradiol concentrations by 50% Alternative methods of nonhormonal contraception should be used when estrogen based oral contraceptives are co-administered with APTIVUS and 200 mg of ritonavir. Patients using estrogens as hormone replacement therapy should be clinically monitored for signs of estrogen deficiency. Women using estrogens may have an increased risk of non-serious rash.

Proton Pump

Inhibitors: Omeprazole ↓ Omeprazole, ↔ Tipranavir Dosage of omeprazole may need to be increased when co-administered with APTIVUS and ritonavir. PDE-5 Inhibitors: Only the combination of tadalafil with APTIVUS/ritonavir has been studied (at doses used for treatment of erectile dysfunction). Co-administration with APTIVUS/ritonavir may result in an increase in PDE-5 inhibitor-associated adverse events, including hypotension, syncope, visual disturbances, and priapism.

Sildenafil Tadalafil

Vardenafil ↑ Sildenafil (not studied) ↑ Tadalafil with first dose APTIVUS/ritonavir ↔ Tadalafil at APTIVUS/ritonavir steady-state ↑ Vardenafil (not studied) Use of PDE-5 inhibitors for pulmonary arterial hypertension (PAH): Use of sildenafil (Revatio) is contraindicated when used for the treatment of pulmonary arterial hypertension (PAH) [ see Contraindications (4) ]. The following dose adjustments are recommended for use of tadalafil (Adcirca) with APTIVUS/ritonavir: Co-administration of tadalafil (Adcirca) in patients on APTIVUS/ritonavir: In patients receiving APTIVUS/ritonavir for at least one week, start Adcirca at 20 mg once daily. Increase to 40 mg once daily based upon individual tolerability. Co-administration of APTIVUS/ritonavir in patients on tadalafil (Adcirca): Avoid use of tadalafil (Adcirca) during the initiation of APTIVUS/ritonavir.

Stop

Adcirca at least 24 hours prior to starting APTIVUS/ritonavir. After at least one week following the initiation of APTIVUS/ritonavir, resume Adcirca at 20 mg once daily. Increase to 40 mg once daily based upon individual tolerability. Use of PDE-5 inhibitors for erectile dysfunction: Concomitant use of PDE-5 inhibitors with APTIVUS/ritonavir should be used with caution and in no case should the starting dose of: sildenafil exceed 25 mg within 48 hours tadalafil exceed 10 mg every 72 hours vardenafil exceed 2.5 mg every 72 hours Use with increased monitoring for adverse events.

Oral

Anticoagulants: Warfarin ↔ S-Warfarin Frequent INR (international normalized ratio) monitoring upon initiation of APTIVUS/ritonavir therapy.

APTIVUS is contraindicated in patients with moderate or severe (Child-Pugh Class B or C, respectively) hepatic impairment [ see Warnings and Precautions (5.2) ]. APTIVUS/ritonavir is contraindicated when co-administered with drugs that are highly dependent on CYP3A for clearance or are potent CYP3A inducers (see Table 1 ) [ see Drug Interactions (7.2) ].

Table

1 Drugs that are Contraindicated with APTIVUS Co-Administered with Ritonavir Drug Class Drugs within Class that are Contraindicated with APTIVUS Co-administered with Ritonavir Clinical Comments: Alpha 1-adrenoreceptor antagonist Alfuzosin Potentially increased alfuzosin concentrations can result in hypotension.

Antiarrhythmics

Amiodarone, bepridil, flecainide, propafenone, quinidine Potential for serious and/or life-threatening reactions such as cardiac arrhythmias secondary to increases in plasma concentrations of antiarrhythmics.

Antimycobacterials Rifampin

May lead to loss of virologic response and possible resistance to APTIVUS or to the class of protease inhibitors or other co-administered antiretroviral agents. Ergot derivatives Dihydroergotamine, ergonovine, ergotamine, methylergonovine Potential for acute ergot toxicity characterized by peripheral vasospasm and ischemia of the extremities and other tissues. GI motility agent Cisapride Potential for cardiac arrhythmias. Herbal products St. John's wort (hypericum perforatum) May lead to loss of virologic response and possible resistance to APTIVUS or to the class of protease inhibitors.

Hmg

CoA reductase inhibitors Lovastatin, simvastatin Potential for myopathy including rhabdomyolysis.

Antipsychotics Pimozide

Potential for cardiac arrhythmias.

Lurasidone

Potential for serious and/or life-threatening reactions. PDE-5 inhibitors Sildenafil (Revatio) [for treatment of pulmonary arterial hypertension] A safe and effective dose has not been established when used with APTIVUS/ritonavir. There is increased potential for sildenafil-associated adverse events (which include visual disturbances, hypotension, prolonged erection, and syncope). Sedatives/hypnotics Oral midazolam, triazolam Prolonged or increased sedation or respiratory depression. Due to the need for co-administration of APTIVUS with ritonavir, please refer to the ritonavir prescribing information for a description of ritonavir contraindications. Patients with moderate or severe (Child-Pugh Class B or C) hepatic impairment ( 4 , 5.2 ) Use with drugs highly dependent on CYP3A for clearance or are potent CYP3A inducers ( 4 , 5.4 , 7 )

AND PRECAUTIONS Co-administration with Ritonavir: APTIVUS must be co-administered with ritonavir and food to achieve the desired antiviral effect. Failure to administer APTIVUS with ritonavir and food may result in a loss of efficacy of tipranavir. ( 5.1 )

Hepatic

Impairment: Discontinue for signs and symptoms of clinical hepatitis or asymptomatic increases in ALT/AST >10 times ULN or asymptomatic increases in ALT/AST 5-10 times ULN with concomitant increases in total bilirubin. Monitor liver function tests prior to therapy and frequently thereafter. ( 5.2 )

Intracranial Hemorrhage/Platelet

Aggregation and Coagulation: Use with caution in patients at risk for increased bleeding or who are receiving medications that increase the risk of bleeding. ( 5.3 , 5.5 ) The concomitant use of APTIVUS/ritonavir and certain other drugs may result in known or potentially significant drug interactions. Consult the full prescribing information prior to and during treatment for potential drug interactions. ( 5.4 , 7.2 ) Rash: Discontinue and initiate appropriate treatment if severe skin reaction occurs or is suspected. ( 5.6 ) Use with caution in patients with a known sulfonamide allergy. ( 5.7 ) Patients may develop new onset or exacerbations of diabetes mellitus, hyperglycemia ( 5.8 ), immune reconstitution syndrome ( 5.9 ), redistribution/accumulation of body fat ( 5.10 ), and elevated lipids. ( 5.11 ) Monitor cholesterol and triglycerides prior to therapy and periodically thereafter. Hemophilia: Spontaneous bleeding may occur, and additional factor VIII may be required. ( 5.12 )

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

5.2 Hepatic Impairment and Toxicity Clinical hepatitis and hepatic decompensation, including some fatalities, were reported with APTIVUS co-administered with 200 mg of ritonavir. These have generally occurred in subjects with advanced HIV-1 disease taking multiple concomitant medications. A causal relationship to APTIVUS/ritonavir could not be established. Physicians and patients should be vigilant for the appearance of signs or symptoms of hepatitis, such as fatigue, malaise, anorexia, nausea, jaundice, bilirubinuria, acholic stools, liver tenderness or hepatomegaly. Patients with signs or symptoms of clinical hepatitis should discontinue APTIVUS/ritonavir treatment and seek medical evaluation. All patients should be followed closely with clinical and laboratory monitoring, especially those with chronic hepatitis B or C co-infection, as these patients have an increased risk of hepatotoxicity. Liver function tests should be performed prior to initiating therapy with APTIVUS/ritonavir, and frequently throughout the duration of treatment. If asymptomatic elevations in AST or ALT greater than 10 times the upper limit of normal occur, APTIVUS/ritonavir therapy should be discontinued. If asymptomatic elevations in AST or ALT between 5 – 10 times the upper limit of normal and increases in total bilirubin greater than 2.5 times the upper limit of normal occur, APTIVUS/ritonavir therapy should be discontinued. Treatment-experienced patients with chronic hepatitis B or hepatitis C co-infection or elevated transaminases are at approximately 2-fold risk for developing Grade 3 or 4 transaminase elevations or hepatic decompensation. In two large, randomized, open-label, controlled clinical trials with an active comparator (1182.12 and 1182.48) of treatment-experienced subjects, Grade 3 and 4 increases in hepatic transaminases were observed in 10.3% (10.9/100 PEY) receiving APTIVUS/ritonavir through week 48. In a study of treatment-naïve subjects, 20.3% (21/100 PEY) experienced Grade 3 or 4 hepatic transaminase elevations while receiving APTIVUS/ritonavir 500 mg/200 mg through week 48. Tipranavir is principally metabolized by the liver. Caution should be exercised when administering APTIVUS/ritonavir to patients with mild hepatic impairment (Child-Pugh Class A) because tipranavir concentrations may be increased [ see Clinical Pharmacology (12.3) ].

5.3 Intracranial Hemorrhage APTIVUS, co-administered with 200 mg of ritonavir, has been associated with reports of both fatal and non-fatal intracranial hemorrhage (ICH). Many of these subjects had other medical conditions or were receiving concomitant medications that may have caused or contributed to these events. No pattern of abnormal coagulation parameters has been observed in subjects in general, or preceding the development of ICH. Therefore, routine measurement of coagulation parameters is not currently indicated in the management of patients on APTIVUS.

5.4 Risk of Serious Adverse Reactions Due to Drug Interactions Initiation of APTIVUS/ritonavir, a CYP3A inhibitor, in patients receiving medications metabolized by CYP3A or initiation of medications metabolized by CYP3A in patients already receiving APTIVUS/ritonavir, may increase plasma concentrations of medications metabolized by CYP3A. Initiation of medications that inhibit or induce CYP3A may increase or decrease concentrations of APTIVUS/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 APTIVUS/ritonavir. Loss of therapeutic effect of APTIVUS/ritonavir and possible development of resistance.

See Table

4 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 APTIVUS/ritonavir therapy; review concomitant medications during APTIVUS/ritonavir therapy; and monitor for the adverse reactions associated with the concomitant medications [ see Contraindications (4) and Drug Interactions (7) ].

5.5 Effects on Platelet Aggregation and Coagulation APTIVUS/ritonavir should be used with caution in patients who may be at risk of increased bleeding from trauma, surgery or other medical conditions, or who are receiving medications known to increase the risk of bleeding such as antiplatelet agents and anticoagulants, or who are taking supplemental high doses of vitamin E. In rats, tipranavir treatment alone induced dose-dependent changes in coagulation parameters, bleeding events and death. Co-administration with vitamin E significantly increased these effects [ see Nonclinical Toxicology (13.2) ]. However, analyses of stored plasma from adult and pediatric subjects treated with APTIVUS capsules plus low-dose ritonavir showed no effect of APTIVUS/ritonavir on vitamin K-dependent coagulation factors (Factor II and Factor VII), Factor V, or on prothrombin or activated partial thromboplastin times. In in vitro experiments, tipranavir was observed to inhibit human platelet aggregation at levels consistent with exposures observed in subjects receiving APTIVUS/ritonavir.

5.6 Rash Rash, including urticarial rash, maculopapular rash, and possible photosensitivity, has been reported in subjects receiving APTIVUS/ritonavir. In some cases rash was accompanied by joint pain or stiffness, throat tightness, or generalized pruritus. In controlled adult clinical trials, rash (all grades, all causality) was observed in 10% of females and in 8% of males receiving APTIVUS/ritonavir through 48 weeks of treatment. The median time to onset of rash was 53 days and the median duration of rash was 22 days. The discontinuation rate for rash in clinical trials was 0.5%. In an uncontrolled compassionate use program (n=3920), cases of rash, some of which were severe, accompanied by myalgia, fever, erythema, desquamation, and mucosal erosions were reported. In the pediatric clinical trial, the frequency of rash (all grades, all causality) through 48 weeks of treatment was 21%. Overall, most of the pediatric subjects had mild rash and 5 (5%) had moderate rash.

Overall

3% of pediatric subjects interrupted APTIVUS treatment due to rash and the discontinuation rate for rash in pediatric subjects was 0.9%. Discontinue and initiate appropriate treatment if severe skin rash develops.

5.7 Sulfa Allergy APTIVUS should be used with caution in patients with a known sulfonamide allergy. Tipranavir contains a sulfonamide moiety. The potential for cross-sensitivity between drugs in the sulfonamide class and APTIVUS is unknown.

5.8 Diabetes Mellitus/Hyperglycemia New onset diabetes mellitus, exacerbation of pre-existing diabetes mellitus and hyperglycemia have been reported during post-marketing surveillance in HIV-1 infected patients receiving protease inhibitor 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 protease inhibitor therapy, hyperglycemia persisted in some cases. Because these events have been reported voluntarily during clinical practice, estimates of frequency cannot be made and a causal relationship between protease inhibitor therapy and these events has not been established.

5.9 Immune Reconstitution Syndrome Immune reconstitution syndrome has been reported in patients treated with combination antiretroviral therapy, including APTIVUS. During the initial phase of combination antiretroviral treatment, patients whose immune system responds may develop an inflammatory response to indolent or residual opportunistic infections (such as Mycobacterium avium infection, cytomegalovirus, Pneumocystis jiroveci pneumonia, tuberculosis, or reactivation of herpes simplex and herpes zoster), which may necessitate further evaluation and treatment. Autoimmune disorders (such as Graves&apos; disease, polymyositis, and Guillain-Barré syndrome) 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 treatment.

5.10 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.

5.11 Elevated Lipids Treatment with APTIVUS co-administered with 200 mg of ritonavir has resulted in large increases in the concentration of total cholesterol and triglycerides [ see Adverse Reactions (6) ]. Triglyceride and cholesterol testing should be performed prior to initiating APTIVUS/ritonavir therapy and at periodic intervals during therapy. Lipid disorders should be managed as clinically appropriate; taking into account any potential drug-drug interactions [ see Drug Interactions (7.2) ].

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

5.13 Resistance/Cross Resistance Because the potential for HIV-1 cross-resistance among protease inhibitors has not been fully explored in APTIVUS/ritonavir treated patients, it is unknown what effect therapy with APTIVUS will have on the activity of subsequently administered protease inhibitors.