Drug-drug:

• ↑levels and risk of toxicity from some antiarrhythmics (amiodarone, dronedarone, flecainide, pimozide, propafenone, quinidine), ergot derivatives (dihydroergotamine, ergotamine, methylergonovine), fluticasone (inhalation), lomitapide, lurasidone, meperidine, ranolazine, sildenafil (Revatio), alfuzosin, lovastatin, simvastatin, voriconazole, midazolam (oral), and triazolam; concurrent use contraindicated.
• May ↑ colchicine levels; concurrent use in patients with renal or hepatic impairment contraindicated; ↓ dose of colchicine in patients without renal or hepatic impairment.
• Apalutamide may ↓ levels and promote resistance; concurrent use contraindicated.
• ↑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 (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 immunosuppressants (cyclosporine, tacrolimus); some antipsychotics (chlorpromazine, haloperidol, perphenazine, risperidone, thioridazine); and also atazanavir, darunavir, fosamprenavir, quinidine, tipranavir, bedaquiline, methamphetamine, and warfarin; dosage ↓ may be necessary.
• May ↑ vincristine and vinblastine levels; consider holding or switching to another antiretroviral regimen that does not contain a CYP3A or P-glycoprotein inhibitor.
• May ↑ dasatinib and nilotinib levels; may need to ↓ doses of dasatinib and nilotinib.
• May ↑ venetoclax and ibrutinib levels and ↑ risk of tumor lysis syndrome; avoid concurrent use.
• May ↑ abemaciclib and neratinib levels and risk of toxicity; avoid concurrent use.
• May ↑ levels and risk of toxicity of glecaprevir/pibrentasvir and sofosbuvir/velpatasvir/voxilaprevir, ombitasvir, and paritaprevir; avoid concurrent use.
• May ↑ levels of systemic, inhaled, nasal, or ophthalmic corticosteroids (betamethasone, budesonide, ciclesonide, dexamethasone, fluticasone, methylprednisolone, mometasone, prednisone, or triamcinolone; consider alternative corticosteroid such as beclomethasone or prednisolone.
• ↓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, causing hypotension, visual changes, priapism; ↓ starting doses not to exceed 25 mg within 48 hr for sildenafil (Viagra), 2.5 mg every 72 hr for vardenafil and 10 mg every 72 hr for tadalafil.
• May ↑ risk of adverse effects with salmeterol; concurrent use not recommended.
• ↑risk of myopathy with atorvastatin or rosuvastatin; use lowest possible dose of statin.
• 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 ritonavir 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 tadalafil (Adcirca), discontinue tadalafil (Adcirca) at least 24 hr before initiation of ritonavir 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.
• May ↑ quetiapine levels; ↓ quetiapine dose to ⅙ of current dose.
• Dexamethasone may ↓ levels/effects; consider use of alternative corticosteroid, such as beclomethasone or prednisolone.
• Encorafenib and ivosidenib may ↑ risk of QT interval prolongation; avoid concurrent use, if possible. If concurrent use necessary, ↓ dose of encorafenib and ivosidenib.
• Concurrent use with elagolix may ↑ elagolix levels and ↓ ritonavir levels; do use with elagolix 200 mg twice daily for longer than 1 mo; do not use with elagolix 150 mg once daily for longer than 6 mo.
• May ↑ levels of active metabolite of fostamatinib, which can ↑ risk of hepatotoxicity and neutropenia; may need to ↓ dose of fostamatinib.

Drug-Natural Products:

• St. John's wort may ↓ levels and promote resistance; concurrent use contraindicated.

• Food↑ absorption.