| Rifabutin (Mycobutin) plus ... |
| Amprenavir |
Decreases amprenavir level by 15% and increases rifabutin level by 193% in blood. Requires lower rifabutin dose. |
| Anticoagulants |
Should be used together with caution. May decrease effectiveness of anticoagulants. Check INR. |
| Atovaquone |
Should be used together with caution. Decreases atovaquone level by 50% in blood. |
| AZT |
May decrease AZT level in blood. |
| Barbiturates |
May decrease effectiveness of barbiturates. |
| Beta-blockers |
May decrease the effectiveness of beta-blockers. Check response to treatment and adjust dose accordingly. |
| Buspirone |
May decrease effectiveness of buspirone. Check symptoms and adjust dose accordingly. |
| Clarithromycin |
Use together with caution. May increase rifabutin level and decrease clarithromycin level in blood. |
| Clofibrate |
May decrease effectiveness of clofibrate. Check response to treatment and adjust dose accordingly. |
| Chloramphenicol |
May decrease the effectiveness of chloramphenicol. Check response to treatment and adjust dose accordingly. |
| Corticosteroids |
May significantly decrease corticosteroid level in blood and require higher doses of corticosteroids. |
| Cyclosporine |
May decrease cyclosporine level in blood. Check cyclosporine blood level and adjust dose accordingly. |
| Dapsone |
Should be used together with caution. May decrease dapsone level in blood. |
| Delavirdine |
Should not be used together*. Significantly decreases delavirdine level and increases rifabutin level in blood. |
| Diazepam |
May decrease effectiveness of diazepam. Check response to treatment and adjust dose accordingly. |
| Digoxin |
Should be used together with caution. May significantly decrease effectiveness of digoxin. Check digoxin level in blood, control of heart rhythm and other cardiac symptoms. |
| Disopyramide |
May decrease effectiveness of disopyramide. Check response to treatment and adjust dose accordingly. |
| Doxycycline |
May decrease effectiveness of doxycycline. Check response to treatment and adjust dose accordingly. |
| Efavirenz |
Decreases rifabutin level in blood. Increase rifabutin dose by 50% if taken daily or double the dose if taken 3 times a week. |
| Estrogen |
Should be used together with caution. May decrease effectiveness of estrogen. |
| Ethinyl estradiol |
Should not be used together. May decrease ethinyl estradiol level in blood. Use another form of contraception. |
| Ethionamide |
Ethionamide may increase risk of side effects from other anti-TB drugs like rifabutin. |
| Fluconazole |
Should be used together with caution. May increase rifabutin level by up to 80% in blood. Increases risk of painful eye inflammation. |
| Fosamprenavir |
Should be used together with great caution. Increases risk of neutropenia. Check for side effects and lower rifabutin dose by at least 50% if fosamprenavir used alone or by 75% if boosted with ritonavir. |
| Glipizide |
Should be used together with caution. May decrease glipizide level in blood. Check blood sugar level and adjust dose accordingly. |
| Glyburide |
Should be used together with caution. May decrease glyburide level in blood. Check blood sugar level and adjust dose accordingly. |
| Indinavir |
Increases rifabutin level by 204% and decreases indinavir level by 32% in blood. Reduce rifabutin dose by half the standard dose and increase indinavir dose to 1,000 mg 3 times a day. |
| Itraconazole |
Should not be used together. May increase rifabutin level and may decrease itraconazole level in blood. |
| Kaletra |
Increases rifabutin level by 5.7-fold in blood. Rifabutin dose should be changed to 150 mg every other day or 3 times a week. Check for rifabutin side effects. |
| Ketoconazole |
Should be used together with caution. May decrease ketoconazole level in blood. |
| Methadone |
May decrease effectiveness of methadone. Check for methadone withdrawal symptoms and adjust methadone dose accordingly. |
| Mexiletine |
May decrease effectiveness of mexiletine. May require lower rifabutin dose. |
| Midazolam |
Should not be used together. Significantly decreases midazolam level in blood. Use alternative to midazolam. |
| Nelfinavir |
Should be used together with caution. Increases rifabutin and decreases nelfinavir levels in blood. Reduce rifabutin dose by one-half and use nelfinavir at 1,250 mg twice a day. |
| Nevirapine |
Should be used together with caution. May significantly affect rifabutin level in blood. |
| Norethindrone |
Should not be used together. May decrease norethindrone level in blood. Use another form of contraception. |
| Opiates |
May decrease effectiveness of opiate drugs. Check pain control and response to treatment and adjust dose accordingly. |
| Phenytoin |
Should be used together with caution. May decrease phenytoin level in blood. Check phenytoin level in blood and seizure activity. Adjust dose accordingly. |
| Probenecid |
Should be used together with caution. May increase rifabutin level in blood and increase risk of side effects. |
| Progesterone |
Should be used together with caution. May decrease effectiveness of progesterone. |
| Quinidine |
May decrease quinidine level in blood. Check response to treatment and adjust dose accordingly. |
| Ritonavir |
Should be used together with caution. Increases rifabutin level by 4-fold in blood. Increases risk of side effects. Rifabutin dose should be reduced to no more than 300 mg once a week or 150 mg every 3 days. Further dose reduction may be necessary. |
| Saquinavir (Fortovase) |
Should be used together with great caution. Decreases saquinavir level by 43% in blood. Consider alternative to rifabutin. |
| Saquinavir (Invirase) |
Should be used together with great caution. Decreases saquinavir level by 40% in blood. Consider alternative to rifabutin. |
| Tolbutamide |
Should be used together with caution. May decrease tolbutamide level in blood. Check blood sugar level and adjust dose accordingly. |
| Theophylline |
May decrease theophylline level in blood. Check theophylline level in blood and adjust dose accordingly. |
| Triazolam |
Should not be used together. Significantly decreases triazolam level in blood. Use alternative to triazolam. |
| Trimetrexate |
Should be used with caution. May affect trimetrexate and/or rifabutin level. |
| Verapamil |
Should not be used together. May significantly decrease effectiveness of verapamil. |
| Zolpidem |
May decrease effectiveness of zolpidem. Check for response to treatment and adjust dose accordingly. |
| Rifampin (Rifadin) plus ... |
| Amprenavir |
Should not be used together*. Significantly decreases amprenavir level in blood. |
| Anticoagulants |
Should be used together with caution. May decrease effectiveness of anticoagulants. Check INR. |
| Atovaquone |
Should be used together with caution. Decreases atovaquone level by 50% in blood. |
| Atazanavir |
Should not be used together. Rifampin decreases level of most protease inhibitors in blood. |
| AZT |
Decreases AZT level by 47% in blood. May require higher AZT dose. |
| Barbiturates |
May decrease effectiveness of barbiturates. |
| Clarithromycin |
Use together with caution. May decrease clarithromycin blood level. |
| Clofibrate |
May decrease effectiveness of clofibrate. Check response to treatment and adjust dose accordingly. |
| Chloramphenicol |
May decrease the effectiveness of chloramphenicol. Check response to treatment and adjust dose accordingly. |
| Corticosteroids |
May significantly decrease corticosteroid level in blood and require higher doses of corticosteroids. |
| Cyclosporine |
May decrease cyclosporine level in blood. Check cyclosporine blood level and adjust dose accordingly. |
| Dapsone |
Should be used together with caution. Decreases dapsone level 7–10 times in blood. |
| Delavirdine |
Should not be used together*, otherwise significantly decreases delavirdine level in blood. |
| Diazepam |
May decrease effectiveness of diazepam. Check response to treatment and adjust dose accordingly. |
| Digoxin |
Should be used together with caution. May significantly decrease effectiveness of digoxin. Check digoxin level in blood, control of heart rhythm and other cardiac symptoms. |
| Disopyramide |
May decrease effectiveness of disopyramide. Check response to treatment and adjust dose accordingly. |
| Doxycycline |
May decrease effectiveness of doxycycline. Check response to treatment and adjust dose accordingly. |
| Efavirenz |
Decreases efavirenz level by 26% in blood. Impact of interaction is uncertain. |
| Estrogen |
Should be used together with caution. May decrease effectiveness of estrogen. |
| Ethinyl estradiol |
Should not be used together. May decrease ethinyl estradiol level in blood. Use another form of contraception. |
| Ethionamide |
May increase risk of side effects from other anti-TB drugs like rifampin. |
| Fluconazole |
Should be used together with caution. Decreases fluconazole level by 23% in blood. May require higher fluconazole dose. |
| Food |
May decrease rifampin level in blood. |
| Fosamprenavir |
Should not be used together*. May decrease anti-HIV activity of fosamprenavir. |
| Glipizide |
Should be used together with caution. May decrease glipizide level in blood. Check blood sugar level and adjust dose accordingly. |
| Glyburide |
Should be used together with caution. May decrease glyburide level in blood. Check blood sugar level and adjust dose accordingly. |
| Halothane |
Should not be used together*. May increase risk of liver toxicity. |
| Indinavir |
Should not be used together*. May increase rifampin level in blood. |
| Isoniazid |
Should be used together with caution. May increase risk of liver toxicity. |
| Itraconazole |
Should not be used together. Decreases rifampin level and may decrease itraconazole level in blood. |
| Ketoconazole |
Should not be used together*. Significantly decreases ketoconazole level in blood. |
| Kaletra |
Should not be used together. Decreases lopinavir level by 75% in blood. |
| Methadone |
May decrease effectiveness of methadone. Check for methadone withdrawal symptoms and adjust methadone dose accordingly. |
| Mexiletine |
May decrease effectiveness of mexiletine. May require lower rifabutin dose. |
| Midazolam |
Should not be used together. Significantly decreases midazolam level in blood. Use alternative to midazolam. |
| Nelfinavir |
Should not be used together*. Decreases nelfinavir level by 82% in blood. |
| Nevirapine |
Should not be used together. Decreases nevirapine level in blood. |
| Norethindrone |
Should not be used together. May decrease norethindrone level in blood. Use another form of contraception. |
| Opiates |
May decrease effectiveness of opiate drugs. Check pain control and response to treatment and adjust dose accordingly. |
| Phenytoin |
Should be used together with caution. May decrease phenytoin level in blood. Check phenytoin level in blood and seizure activity. Adjust dose accordingly. |
| Probenecid |
Should be used together with caution. May increase rifampin level in blood and increase risk of side effects. |
| Progesterone |
Should be used together with caution. May decrease effectiveness of progesterone. |
| Quinidine |
May decrease quinidine level in blood. Check response to treatment and adjust dose accordingly. |
| Ritonavir |
Should not be used together. Decreases ritonavir level by 35% in blood. Consider using rifabutin instead. |
| Saquinavir (Fortovase) |
Should not be used together. Decreases saquinavir level by 84% in blood. |
| Saquinavir (Invirase) |
Should not be used together. Decreases saquinavir level by 80% in blood. |
| Theophylline |
May decrease theophylline level in blood. Check theophylline level in blood and adjust dose accordingly. |
| Triazolam |
Should not be used together. Significantly decreases triazolam level in blood. Use alternative to triazolam. |
| Trimetrexate |
Should be used together with caution. May affect trimetrexate and/or rifampin level in blood. |
| Verapamil |
Should not be used together. May significantly decrease effectiveness of verapamil. |
| Zolpidem |
May decrease effectiveness of zolpidem. Check for response to treatment and adjust dose accordingly. |
| Ritonavir (Norvir) plus ... |
| Alfentanil |
Should be used with caution. May significantly increase alfentanil level in blood. May require lower alfentanil dose. |
| Alprazolam |
Should be used together with caution. Although ritonavir decreases alprazolam level in blood, it may also prolong sedation. |
| Amiodarone |
Should not be used together*. Increases risk of side effects. |
| Amitriptyline |
Should be used together with great caution. May increase amitriptyline level in blood. May require lower amitriptyline dose. |
| Amlodipine |
Should be used together with caution. May significantly increase amlodipine level in blood. May require lower amlodipine dose. |
| Amoxapine |
Should be used together with great caution. May increase amoxapine level in blood. May require lower amoxapine dose. |
| Amprenavir |
Increases amprenavir level by 70% in blood. Alternate dosing is amprenavir 600 mg + ritonavir 100 mg twice a day, or amprenavir 1,200 mg + ritonavir 200 mg once daily. |
| Astemizole |
Should not be used together*. Increases risk of side effects. |
| Atazanavir |
Substantially increases atazanavir level in blood. If combined, use atazanavir 300 mg once a day (with food) + ritonavir 100 mg once a day. |
| Atorvastatin |
Should be used together with great caution. Ritonavir + saquinavir increases atorvastatin level by 343% in blood. Use lowest dose of atorvastatin or consider using pravastatin. |
| Atovaquone |
May decrease atovaquone level in blood. |
| AZT |
Decreases AZT level by 25% in blood. No dose adjustment recommended. |
| Bepridil |
Should not be used together*. Increases risk of side effects. |
| Bromocriptine |
Should be used together with caution. May significantly increase bromocriptine level in blood. May require lower bromocriptine dose. |
| Buproprion |
Should be used together with caution. Increases risk of side effects. |
| Buprenorphine |
Should be used with caution. May significantly increase buprenorphine level in blood. May require lower buprenorphine dose. |
| Butorphanol |
Should be used with caution. May significantly increase butorphanol level in blood. May require lower butorphanol dose. |
| Carbamazepine |
Should be used together with caution. May significantly increase carbamazepine level in blood. May require lower carbamazepine dose. |
| Chlorpromazine |
Should be used together with caution. May increase chlorpromazine level in blood. Check for side effects. |
| Cisapride |
Should not be used together*. Increases risk of side effects. |
| Citalopram |
Should be used together with caution. May increase citalopram level in blood. May require lower citalopram dose. |
| Clarithromycin |
Increases clarithromycin level by 77% and increases ritonavir level by 12% in blood. Requires lower dose of clarithromycin and checking for kidney toxicity in people with a history of kidney problems. |
| Clofibrate |
May decrease clofibrate level in blood. |
| Clomipramine |
Should be used together with caution. May increase clomipramine level in blood. May require dose reduction of clomipramine. |
| Clonazepam |
Should be used together with caution. May increase clonazepam level in blood. May require dose reduction of clonazepam. |
| Clorazepate |
Should be used together with caution. Increases risk of side effects. |
| Clotrimazole |
May increase risk of side effects. |
| Clozapine |
Should not be used together*. Increases risk of side effects. |
| Codeine |
Should be used with caution. May decrease codeine level in blood. May require lower codeine dose. |
| Cyclosporine |
May significantly increase cyclosporine level in blood. |
| ddI or ddI EC |
Decreases ddI level by 13% in blood. No dose adjustment recommended, but take 2½ hours apart. |
| Delavirdine |
Increases ritonavir level by about 51% in blood. May require lower ritonavir dose. |
| Desipramine |
Should be used together with caution. Increases desipramine level by 145% in blood. Check desipramine level in blood and adjust dose accordingly. |
| Dexamethasone |
Should be used together with caution. May significantly increase dexamethasone level in blood. May require lower dexamethasone dose. |
| Diazepam |
Should be used together with caution. Increases risk of side effects. |
| Dihydroergotamine |
Should not be used together*. Increases risk of side effects. |
| Diltiazem |
Should be used together with caution. May significantly increase diltiazem level in blood. May require lower diltiazem dose. |
| Diphenoxylate |
May decrease diphenoxylate level in blood. |
| Disopyramide |
Should be used together with caution. May increase disopyramide level in blood and increase heart (cardiac) and brain/nerve (neurological) side effects. May require lower disopyramide dose. |
| Divalproex |
Should be used together with caution. May decrease divalproex level in blood. A higher divalproex dose may be necessary. |
| Doxepin |
Should be used together with caution. May increase doxepin level in blood. May require lower doxepin dose. |
| Dronabinol |
Should be used together with caution. May increase dronabinol level in blood. May require lower dronabinol dose. |
| Efavirenz |
Should be used together with caution. Increases efavirenz level by 21% and ritonavir level by 18% in blood. Check for side effects. |
| Encainide |
Should not be used together*. Increases risk of side effects. |
| Enfuvirtide |
Ritonavir used at the full dose increases enfuvirtide level by 22% in blood. Ritonavir at a boosting dose of 100 mg twice a day increases enfuvirtide level by 14% in blood. No dose adjustment recommended. |
| Ergonovine |
Should not be used together*. Increases risk of side effects. |
| Ergotamine |
Should not be used together*. Increases risk of side effects. |
| Erythromycin |
Should be used together with caution. May increase erythromycin level in blood. May require lower erythromycin dose. |
| Escitalopram |
Should be used together with caution. May increase escitalopram level in blood. May require lower escitalopram dose. |
| Estazolam |
Should be used together with caution. Increases risk of side effects. |
| Ethinyl estradiol |
Should not be used together. Decreases ethinyl estradiol level by 40% in blood. Use another form of contraception. |
| Ethosuximide |
Should be used together with caution. May increase ethosuximide level in blood. May require lower ethosuximide dose. |
| Etoposide |
Should be used with great caution. May increase etoposide level in blood and increase risk of side effects. |
| Felodipine |
Should be used together with caution. May significantly increase felodipine level in blood. May require lower felodipine dose. |
| Fentanyl |
Should be used together with caution. May significantly increase fentanyl level in blood. May require lower fentanyl dose. |
| Flecainide |
Should not be used together*. Increases risk of side effects. |
| Flucitasone propionate |
Should not be used together. Increases risk of side effects. |
| Fluconazole |
Increases ritonavir level by 12% in blood. No dose adjustment recommended; however, check for liver toxicity. |
| Fluoxetine |
Should be used together with great caution. May increase risk of serious side effects. May require lower fluoxetine dose. |
| Flurazepam |
Should be used together with caution. Increases risk of side effects. |
| Fluvastatin |
Should be used together with caution. May increase fluvastatin level in blood. Check for toxicity. |
| Fluvoxamine |
Should be used together with caution. May increase fluvoxamine level in blood. May require lower fluvoxamine dose. |
| Food |
Increases ritonavir level in blood. |
| Fosamprenavir |
Increases fosamprenavir level in blood. Adjust dose to fosamprenavir 700 mg + ritonavir 100 mg twice a day or fosamprenavir 1,400 mg + ritonavir 200 mg once a day. |
| Foscarnet |
Should be used with caution. Abnormal kidney function has been observed. |
| Haloperidol |
Should be used together with caution. May increase haloperidol level in blood. Check for side effects. |
| Hydrocodone |
Should be used with caution. May significantly increase hydrocodone level in blood. May require lower hydrocodone dose. |
| Hydromorphone |
Should be used with caution. May significantly increase hydromorphone level in blood. May require lower hydromorphone dose. |
| Imipramine |
Should be used together with caution. May increase imipramine level in blood. May require lower imipramine dose. |
| Indinavir |
Ritonavir significantly increases indinavir level in blood. Adjust dose to indinavir 800 mg + ritonavir 200 mg twice a day or indinavir 400 mg + ritonavir 400 mg twice a day. |
| Isradipine |
Should be used together with caution. May significantly increase isradipine level in blood. May require lower isradipine dose. |
| Itraconazole |
Should be used together with caution. May significantly increase itraconazole level in blood. |
| Ketoconazole |
Should be used together with caution. Significantly increases ketoconazole level in blood. Ketoconazole dose should not exceed 200 mg/day. |
| Ketoprofen |
May increase ketoprofen level in blood. |
| Ketorolac |
May increase ketorolac level in blood. |
| Lamotrigine |
Should be used together with caution. May decrease lamotrigine level in blood. A higher lamotrigine dose may be necessary. |
| Lidocaine |
Should be used together with caution. May significantly increase lidocaine level in blood. May require lower lidocaine dose. |
| Loperamide |
Should not be used together. Decreases the effectiveness of loperamide. |
| Loratadine |
Should be used together with caution. May increase loratadine level in blood. Check for side effects. |
| Lorazepam |
May increase lorazepam level in blood. |
| Lovastatin |
Should not be used together. May significantly increase lovastatin level in blood. |
| Maprotiline |
Should be used together with caution. May increase maprotiline level in blood. Check for side effects. |
| Mefloquine |
Should be used with great caution. May significantly decrease ritonavir level in blood. |
| Meperidine |
Decreases meperidine level in blood, but leads to increased concentrations of the active metabolite normeperidine over time. Long-term use in combination at higher meperidine doses is not recommended. |
| Methadone |
Decreases methadone level by about 40% in blood. Check for methadone withdrawal symptoms and adjust methadone dose accordingly. |
| Methamphetamine |
Caution is warranted. May increase methamphetamine level in blood. |
| Methylergonovine |
Should not be used together*. Increases risk of side effects. |
| Metoclopramide |
May decrease metoclopramide level in blood. |
| Metoprolol |
Should be used together with caution. May increase metoprolol level in blood. May require lower metoprolol dose. |
| Metronidazole |
Should be used together with caution. May increase risk of side effects (ritonavir liquid only). |
| Mexiletine |
Should be used together with caution. May increase mexiletine level in blood and increase heart (cardiac) and brain/nerve (neurological) side effects. May require lower mexiletine dose. |
| Miconazole |
Should be used together with caution. May increase miconazole level in blood. Check for side effects. |
| Midazolam |
Should not be used together*. Increases risk of side effects. |
| Morphine |
Should be used together with caution. May decrease morphine level in blood. Check for pain management and possible withdrawal symptoms and adjust dose accordingly. |
| Naproxen |
May increase naproxen level in blood. |
| Nefazadone |
Should be used together with caution. May significantly increase nefazadone level in blood and increase cardiac and neurological side effects. May require dose reduction of nefazadone. |
| Nelfinavir |
Increases ritonavir level by 9% and increases nelfinavir level by 152% in blood. Other dose under study includes nelfinavir 500–750 mg + ritonavir 400 mg twice a day. |
| Nevirapine |
Decreases ritonavir level by 11% in blood. No dose adjustment recommended. |
| Nicardipine |
Should be used together with caution. May significantly increase nicardipine level in blood. May require lower nicardipine dose. |
| Nifedipine |
Should be used together with caution. May significantly increase nifedipine level in blood. May require lower nifedipine dose. |
| Nimodipine |
Should be used together with caution. May significantly increase nimodipine level in blood. May require lower nimodipine dose. |
| Nisoldipine |
Should be used together with caution. May significantly increase nisoldipine level in blood. May require lower nisoldipine dose. |
| Nitrendipine |
Should be used together with caution. May significantly increase nitrendipine level in blood. May require lower nitrendipine dose. |
| Nortriptyline |
Should be used together with caution. May increase nortriptyline level in blood. May require lower nortriptyline dose. |
| Ondansetron |
Should be used together with caution. May increase ondansetron level in blood. Check for side effects. |
| Oxazepam |
May increase oxazepam level in blood. |
| Oxycodone |
Should be used with caution. May significantly increase oxycodone level in blood. May require lower oxycodone dose. |
| Paclitaxel |
Should be used together with caution. May increase paclitaxel level in blood. Check for side effects. |
| Paroxetine |
Should be used together with caution. May increase paroxetine level in blood. May require lower paroxetine dose. |
| Penbutolol |
Should be used together with caution. May increase penbutolol level in blood. May require lower penbutolol dose. |
| Pentazocine |
Should be used with caution. May significantly increase pentazocine level in blood. May require lower pentazocine dose. |
| Perphenazine |
Should be used together with caution. May increase perphenazine level in blood. May require lower perphenazine dose. |
| Phenytoin |
Should be used together with caution. May decrease phenytoin level in blood. An increased dose of phenytoin may be necessary. |
| Pimozide |
Should not be used together*. Increases risk of side effects. |
| Pindolol |
Should be used together with caution. May increase pindolol level in blood. Check for side effects. |
| Piroxicam |
Should not be used together*. Increases risk of side effects. |
| Pravastatin |
No clinically significant interactions with ritonavir as sole protease inhibitor. However, ritonavir + saquinavir decreases pravastatin level by 47% in blood. |
| Prednisone |
Should be used together with caution. May increase prednisone level in blood. May require lower dexamethasone dose. |
| Propafenone |
Should not be used together*. Increases risk of side effects. |
| Propoxyphene |
Should be used together with caution. Increases risk of side effects. |
| Protriptyline |
Should be used together with caution. May increase protriptyline level in blood. May require lower protriptyline dose. |
| Quinine |
Should be used together with caution. May significantly increase quinine level in blood. May require lower quinine dose. |
| Quinidine |
Should not be used together*. Increases risk of side effects. |
| Rapamycin |
Should be used together with caution. May significantly increase rapamycin level in blood. May require lower rapamycin dose. |
| Rifabutin |
Should be used together with caution. Increases rifabutin level by 4-fold in blood. Increases risk of side effects. Rifabutin dose should be reduced to no more than 300 mg once a week or 150 mg every 3 days. Further dose reduction may be necessary. |
| Rifampin |
Should not be used together. Decreases ritonavir level by 35% in blood. Consider using rifabutin instead. |
| Risperidone |
Should be used together with caution. May increase risperidone level in blood. May require lower risperidone dose. |
| Saquinavir (Fortovase) |
Increases saquinavir level by 1,587% in blood. Adjust doses to saquinavir 1,000 mg + ritonavir 100 mg twice a day. |
| Saquinavir (Invirase) |
Increases saquinavir level by about 20 times in blood. Adjust doses to saquinavir 1,000 mg + ritonavir 100 mg twice a day. |
| Sertraline |
Should be used together with caution. May significantly increase sertraline level in blood. May require lower sertraline dose. |
| Sildenafil |
Should be used with caution. Increases sildenafil level by 11 times in blood. Sildenafil dose should not exceed 25 mg within a 48 hour period. |
| Simvastatin |
Should not be used together. Ritonavir + saquinavir increases simvastatin level by 3,059% in blood. |
| St. John's Wort |
Should not be used together. May significantly decrease ritonavir level in blood. |
| Tacrolimus |
Should be used together with caution. May significantly increase tacrolimus level in blood. May require lower tacrolimus dose. |
| Tamoxifen |
Should be used together with caution. May significantly increase tamoxifen level in blood. Check for side effects. |
| Tedalafil |
Should be used together with caution. Increases tedalafil level in blood. Tedalafil dose should not exceed 10 mg in a 72 hour period. |
| Temazepam |
May increase temazepam level in blood. |
| Theophylline |
Decreases theophylline level by 43% in blood. Check theophylline level in blood and adjust dose accordingly. |
| Thioridazine |
Should be used together with caution. May increase thioridazine level in blood. May require lower thioridazine dose. |
| Timolol |
Should be used together with caution. May increase timolol level in blood. May require lower timolol dose. |
| Tipranavir |
Increases tipranavir level 12 times and decreases ritonavir level by 75–80% in blood. Other doses now under study. |
| Tramadol |
Should be used together with caution. May increase tramadol level in blood. May require lower tramadol dose. |
| Trazodone |
Increases trazodone level in blood. Trazodone dose may need to be reduced. |
| Triazolam |
Should not be used together*. Increases risk of side effects. |
| Trimipramine |
Should be used together with caution. May increase trimipramine level in blood. May require lower trimipramine dose. |
| Vardenafil |
Should be used together with caution. Increases vardenafil level in blood. Vardenafil dose should not exceed 2.5 mg in a 72 hour period. |
| Venlafaxine |
Should be used together with caution. May increase venlafaxine level in blood. May require lower venlafaxine dose. |
| Verapamil |
Should be used together with caution. May significantly increase verapamil level in blood. May require lower verapamil dose. |
| Vinblastine |
Should be used together with caution. May increase vinblastine level in blood. Check for side effects. |
| Vincristine |
Should be used together with caution. May increase vincristine level in blood. Check for side effects. |
| Voriconazole |
Should not be used together. Increases risk of side effects. |
| Warfarin |
Should be used together with caution. May decrease warfarin level in blood. A higher warfarin dose may be necessary; however, closely check INR. |
| Zolpidem |
Should be used together with caution. Increases risk of side effects. |
