Drug-Drug

• ↑ blood levels and risk of toxicity from some antiarrhythmics ( amiodarone , flecainide , pimozide , propafenone , quinidine ), ergot derivatives ( dihydroergotamine , ergonovine , ergotamine , methylergonovine ), fluticasone (inhalation) , meperidine , sildenafil (Revatio) , alfuzosin , lovastatin , simvastatin , voriconazole , midazolam (oral) , and triazolam ; avoid concomitant use.

• ↑ levels of maraviroc ; ↓ maraviroc dose to 150 mg twice daily.

• ↑ levels of clarithromycin ; ↓ clarithromycin dose if CCr <60 mL/min.

• ↑ levels of rifabutin ; ↓ rifabutin dose to 150 mg every other day or 3 times weekly.

• May also ↑ levels and effects of some opioid analgesics ( alfentanil , fentanyl , hydrocodone , oxycodone ), tramadol ; some NSAIDs ( diclofenac , ibuprofen , indomethacin ); some antiarrhythmics ( disopyramide , lidocaine , mexiletine ); many antidepressants ( amitriptyline , clomipramine , desipramine , imipramine , nortriptyline , nefazodone , sertraline , trazodone , fluoxetine , paroxetine , venlafaxine ); some antiemetics ( dronabinol , ondansetron ); some beta blockers ( metoprolol , pindolol , propranolol , timolol ); many calcium channel blockers ( amlodipine , diltiazem , felodipine , isradipine , nicardipine , nifedipine , nimodipine , nisoldipine , verapamil ); some antineoplastics ( etoposides , paclitaxel , tamoxifen , vinblastine , vincristine ); some corticosteroids ( dexamethasone , prednisone ), most HMG CoA reductase inhibitors ; some immunosuppressants ( cyclosporine , tacrolimus ); some antipsychotics ( chlorpromazine , haloperidol , perphenazine , risperidone , thioridazine ); and also quinidine , saquinavir , methamphetamine , and warfarin . Dosage ↓ may be necessary.

• ↓ levels and effects of hormonal contraceptives , zidovudine , bupropion , and theophylline ; dose alteration or alternative therapy may be necessary.

• Levels may be ↑ by clarithromycin or fluoxetine .

• ↑ risk of heart block with beta blockers , verapamil , diltiazem , digoxin , or atazanavir .

• May ↑ concentrations of phosphodiesterase type 5 inhibitors (PDE5) causing hypotension, visual changes, priapism; ↓ starting doses not to exceed 25 mg within 48 hr for sildenafil (Viagra), 2.5 mg q 72 hr for vardenafil and 10 mg q 72 hr for tadalafil .

• May ↑ risk of adverse effects with salmeterol ; concurrent use not recommended.

• May ↑ bosentan levels; initiate bosentan at 62.5 mg once daily or every other day; if patient already receiving bosentan, discontinue bosentan at least 36 hr before initiation of tipranavir and then restart bosentan at least 10 days later at 62.5 mg once daily or every other day.

• May ↑ tadalafil (Adcirca) levels; initiate tadalafil (Adcirca) at 20 mg once daily; if patient already receiving tadalfil (Adcirca), discontinue tadalafil (Adcirca) at least 24 hr before initiation of tipranavir and then restart tadalafil (Adcirca) at least 7 days later at 20 mg once daily.

• May ↑ colchicine levels; ↓ dose of colchicine; do not administer colchicine if patients have renal or hepatic impairment.

Drug-Natural Products
St. John's wort ↓ levels and may promote resistance; avoifd concomitant use.

Drug-Food
Food ↑ absorption.