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Back to interaction table   Drug interactions between abacavir and amprenavir
Interaction In vitro results suggest that abacavir is not metabolized by the cytochrome enzymes. An interaction with amprenavir doesn't look likely to happen.
Recommendation No specific action is required.
References 129,130,131


Back to interaction table   Drug interactions between abacavir and indinavir
Interaction In vitro results suggest that abacavir is not metabolized by the cytochrome enzymes. An interaction with amprenavir doesn't look likely to happen.
Recommendation No specific action is required.
References 129


Back to interaction table   Drug interactions between abacavir and lamivudine
Interaction The AUC of lamivudine decreases by 15%, but this doesn't lead to a clinically significant drug interaction. 
Recommendation No specific action is required.
References 131,132


Back to interaction table   Drug interactions between abacavir and nelfinavir
Interaction In vitro results suggest that abacavir is not metabolized by the cytochrome enzymes. An interaction with nelfinavir doesn't look likely to happen.
Recommendation No specific action is required.
References 129


Back to interaction table   Drug interactions between abacavir and ritonavir
Interaction In vitro results suggest that abacavir is not metabolized by the cytochrome enzymes. An interaction with amprenavir doesn't look likely to happen.
Recommendation No specific action is required.
References 129


Back to interaction table   Drug interactions between abacavir and saquinavir
Interaction In vitro results suggest that abacavir is not metabolized by the cytochrome enzymes. An interaction with saquinavir doesn't look likely to happen.
Recommendation No specific action is required.
References 129,130


Back to interaction table   Drug interactions between abacavir and zidovudine
Interaction The AUC of zidovudine increases by 24%, but this doesn't lead to a clinically significant drug interaction. 
Recommendation No specific action is required.
References 129,131


Back to interaction table   Drug interactions between amprenavir and efavirenz
Interaction Efavirenz induces CYP3A4. This results in a decrease of the AUC of amprenavir by 36%, of his Cmax by 39% and of his Cmin by 45%.
The AUC of efavirenz increases by 15%.
This doesn't lead to a clinically significant drug interaction. 
Recommendation No adjustment of dosage necessary.
References 131,133


Back to interaction table   Drug interactions between amprenavir and indinavir
Interaction The AUC of indinavir decreases by 38%, his Cmin decreases by 27% and his Cmax by 22%.
The AUC of amprenavir increases by 22 to 26%
This doesn't lead to a clinically significant drug interaction. 
Recommendation No adjustment of dosage necessary.
References 131,133,134


Back to interaction table   Drug interactions between amprenavir and lamivudine
Interaction There is no clinically significant drug interaction.
Recommendation No specific action is required.
References 131


Back to interaction table   Drug interactions between amprenavir and nelfinavir
Interaction The AUC of amprenavir isn't affected but his Cmin increases by 167%.
The AUC of nelfinavir increases by 15%.
Recommendation No adjustment of dosage necessary.
References 131


Back to interaction table   Drug interactions between amprenavir and ritonavir
Interaction The AUC of amprenavir increases by 700% and his Cmax by 80%. This is the result of the inhibition of metabolization (CYP-enzymes) by ritonavir.
Recommendation no info
References 130


Back to interaction table   Drug interactions between amprenavir and saquinavir
Interaction Saquinavir (soft gel) decreases the AUC of amprenavir by 36%.
The AUC of saquinavir (sot gel) decreases by 18%.
Recommendation No adjustment of dosage should be necessary, but monitor the clinical efficacy of this combination and adjust the dose if necessary.
References 131


Back to interaction table   Drug interactions between amprenavir and zidovudine
Interaction The AUC of zidovudine increases by 31%, but this doesn't lead to a clinically significant drug interaction.
Recommendation No adjustment of dosage necessary.
References 131


Back to interaction table   Drug interactions between delavirdine and didanosine
Interaction The AUC of delavirdine decreases by 22% to 28% and his Cmax decreases by 53%.
The AUC of didanosine decreases by 17% to 20%.
Recommendation Space the administration of delavirdiner and didanosine by at least 1 hour.
References 135,136,137,131,132,133,138,139


Back to interaction table   Drug interactions between delavirdine and indinavir
Interaction The AUC of indinavir increases by 40% to 100%, his Cmax decreases and his Cmin increases. This is the result of the CYP3A4 inhibition by delavirdine.
Recommendation Adjustment in dosage are necessary (Decrease the dose of indinavir to 600mg)
References 137,131,133,134,140


Back to interaction table   Drug interactions between delavirdine and lamivudine
Interaction The AUC of delavirdine decreases by 42%, but this doesn't lead to a clinically significant drug interaction.
Recommendation No specific action is required.
References 141,142


Back to interaction table   Drug interactions between delavirdine and nelfinavir
Interaction The AUC of delavirdine decreases by 42%, his Cmax by 34%.
The AUC of nelfinavir increases by 90% to 100%.
This probably doesn't lead to a clinically significant drug interaction.
Toxicity Concomitant use can lead to increased incidence of neutropenia and leukopenia..
Recommendation Pobably no adjustment of dosage necessary, but monitor blood work and signs and symptoms of neutropenia and leukopenia.
References 142,143,131,133


Back to interaction table   Drug interactions between delavirdine and ritonavir
Interaction The AUC of ritonavir increases by 70% to 78%, presumably through inhibition of ritonavir oxidative metabolism.
Recommendation Adjustment in dosage are necessary
References 131,133,132


Back to interaction table   Drug interactions between delavirdine and saquinavir
Interaction The AUC of saquinavir increases by 400% and the AUC of delavirdine decreases by 24%.
Recommendation Adjustment in dosage are necessary
References 135


Back to interaction table   Drug interactions between didanosine and indinavir
Interaction The buffered vehicle for didanosine (i.e., a magnesium/aluminum antacid) produces an acutely alkaline gastric environment that may decrease the absorption of indinavir, which needs a acidic environment for absorption.
Recommendation Space the administration of indinavir and didanosine by at least 1 hour. Preferably, administer indinavir 1 before or 2 hour(s) after didanosine.
References 135,136,137,141,144

Back to interaction table   Drug interactions between didanosine and lamivudine
Interaction There is no clinically significant drug interaction. 
Recommendation No specific action is required.
References 141


Back to interaction table   Drug interactions between didanosine and nelfinavir
Interaction There is no clinically significant drug interaction.
Recommendation Because didanosine should be taken without food and nelfinavir with food, nelfinavir should be administered 2 hours before or 1 hour after didanosine. 
References 142,143,132


Back to interaction table   Drug interactions between didanosine and nevirapine
Interaction There is no clinically significant drug interaction.
Recommendation No adjustment of dosage necessary.
References 145,146


Back to interaction table   Drug interactions between didanosine and ritonavir
Interaction Ritonavir seems to reduce didanosine bioavailability. The AUC of didanosine decreases by 13% and its Cmax by 16% . This doesn't seem to lead to a clinically significant drug interaction.
Recommendation No adjustment of dosage necessary.
Space the administration of ritonavir and didanosine by at least 2,5 hours to avoid interactions between both formulations..
References 135,147,137,148,131,132


Back to interaction table   Drug interactions between didanosine and stavudine
Interaction There is no clinically significant drug interaction.
Toxicity Concomitant use can lead to an increased risk of peripheral neuropathy.
Recommendation No adjustment of dosage necessary, but monitor for signs and symptoms of peripheral neuropathy: numbness, burning dysesthesia and weakness involving the distal extremeties, tingling. 
References 136,147,141,133,138,149


Back to interaction table   Drug interactions between didanosine and zalcitabine
Interaction There is no clinically significant drug interaction.
Toxicity Concomitant use can lead to an increased risk of peripheral neuropathy and pancreatitis.
Recommendation Concomitant use is dissuaded
Monitor for signs and symptoms of peripheral neuropathy: numbness, burning dysesthesia and weakness involving the distal extremeties, tingling.
Monitor for signs and symptoms of pancreatitis (abdominal pain, nausea, vomiting).
Monitor amylases and lipases concentrations monthly.
References 135,136,137,141,133,139,150,151,152


Back to interaction table   Drug interactions between didanosine and zidovudine
Interaction The AUC of didanosine decreases by 19% and the AUC of zidovudine increases by 35%, but this doesn't lead to a clinically significant drug interaction.
Toxicity Concomitant use can lead to an increased risk of peripheral neuropathy.
Recommendation No adjustment of dosage necessary, but monitor for signs and symptoms of peripheral neuropathy: numbness, burning dysesthesia and weakness involving the distal extremeties, tingling.
References 147,138,139,151,153,154


Back to interaction table   Drug interactions between efavirenz and indinavir
Interaction As a result of the CYP3A4 induction of efavirenz, the AUC of indinavir decreases by 30% to 35% and the Cmax decreases by 16%.
Recommendation Adjustment in dosage are necessary (it is recommended to increase the dose of indinavir to 1000 mg)
References 131,133,134,155


Back to interaction table   Drug interactions between efavirenz and lamivudine
Interaction There is no clinically significant drug interaction.
Recommendation No specific action is required.
References 131,155


Back to interaction table   Drug interactions between efavirenz and nelfinavir
Interaction There is no clinically significant drug interaction.
Recommendation No specific action is required.
References 143


Back to interaction table   Drug interactions between efavirenz and ritonavir
Interaction The AUC of efavirenz increases by 21% and the AUC of ritonavir increases by 17% to 18%.
Recommendation Adjustment in dosage are necessary (it is recommended to decrease the dose of ritonavir to 500 mg)
Monitor the liver enzymes of patients.
References 155


Back to interaction table   Drug interactions between efavirenz and zidovudine
Interaction There is no clinically significant drug interaction.
Recommendation No specific action is required.
References 131,155


Back to interaction table   Drug interactions between indinavir and lamivudine
Interaction The AUC of lamivudine decreases by 6%, but this doesn't lead to a clinically significant drug interaction. Both drugs have different metabolisation pathways.
Recommendation No specific action is required.
References 135,141,132


Back to interaction table   Drug interactions between indinavir and nelfinavir
Interaction Nelfinavir decreases the elimination of indinavir, which causes an increase of the AUC of indinavir by 51%
The AUC of nelfinavir increases by 83% to 84% and his Cmax increases by 31%. This is caused by an inhibition of CYP3A.
Recommendation no info
References 142,143,134


Back to interaction table   Drug interactions between indinavir and nevirapine
Interaction Nevirapine decreases the AUC of indinavir by 25 to 30%, his Cmax by 11% and his Cmin 38%. This is the result of the CYP3A4 induction by nevirapine.
The nevirapine AUC decreases less than 10%.
The clinical significance of this interaction is unknown.
Recommendation Concomitant use is dissuaded till new research brings clearness.
Adjustment in dosage are necessary (it is recommended to increase the dose of indinavir to 1000 mg and monitor for signs and symptoms of indinavir therapeutic failure.)
References 135,137,141,156,131,133,145


Back to interaction table   Drug interactions between indinavir and ritonavir
Interaction Ritonavir inhibits the metabolisation of indinavir.This results in an increase of the AUC of indinavir by 200% to 500%.
Recommendation Adjustment in dosage are necessary (Indinavir and ritonavir both 400mg 2x a day)
References 131,133,134,157


Back to interaction table   Drug interactions between indinavir and saquinavir
Interaction Indinavir may inhibit the hepatic metabolism of saquinavir. The AUC of saquinavir increases by 360% to 620 % and his Cmax by 551%
Recommendation Adjustment in dosage are necessary
References 135,158,131,133,134


Back to interaction table   Drug interactions between indinavir and stavudine
Interaction The AUC of stavudine is increases by 25% whereas the AUC indinavir remains unchanged, but this doesn't lead to a clinically significant drug interaction.
Recommendation No dosage adjustment is necessary. 
References 135,147,141,132


Back to interaction table   Drug interactions between indinavir and zidovudine
Interaction The AUC of zidovudine increases by 17% to 35% and the AUC of indinavir increases by 13%, but this doesn't lead to a clinically significant drug interaction.
Recommendation No dosage adjustment is necessary.
References 135,147,132


Back to interaction table   Drug interactions between lamivudine and nelfinavir
Interaction The AUC of lamivudine increased by 10% and the Cmax increased by 31%, but this doesn't lead to a clinically significant drug interaction. Both drugs have different metabolisation pathways.
Recommendation No specific action is required. 
References 135,141,142,143


Back to interaction table   Drug interactions between lamivudine and nevirapine
Interaction There is no clinically significant drug interaction.
Recommendation No specific action is required.
References 141,145


Back to interaction table   Drug interactions between lamivudine and ritonavir
Interaction There is no clinically significant drug interaction. Both drugs have different elimination routes.
Recommendation No specific action is required.
References 141


Back to interaction table   Drug interactions between lamivudine and zalcitabine
Interaction There is no clinically significant drug interaction, but due to the competion for the same enzyme the phosphorylation of zalcitabine in vitro was decreased.
Toxicity
 Concomitant administration can lead to an increased risk of peripheral neuropathy.
Recommendation No adjustment of dosage necessary, but monitor for signs and symptoms of peripheral neuropathy: numbness, burning dysesthesia and weakness involving the distal extremeties, tingling. 
References 141,133,159


Back to interaction table   Drug interactions between lamivudine and zidovudine
Interaction The Cmax of zidovudine increases, but this doesn't lead to a clinically significant drug interaction.
Recommendation No adjustment of dosage necessary.
References 135,147,141,138,144,159


Back to interaction table   Drug interactions between nelfinavir and nevirapine
Interaction The  AUC of nelfinavir decreases by 10% to 20%
Recommendation Adjustment in dosage are necessary (Increase the dose of nelfinavir from 750mg to 1000mg 3x a day)
References 137,141,143,131,160


Back to interaction table   Drug interactions between nelfinavir and ritonavir
Interaction Ritonavir inhibits the metabolisation nelfinavir. The AUC of ritonavir remaines unchanged. The AUC of nelfinavir increased by 152%.
Recommendation Adjustment in dosage are necessary (ritonavir 400mg 2x a day and nelfinavir 750mg 2x a day)
References 135,142,143


Back to interaction table   Drug interactions between nelfinavir and saquinavir
Interaction Nelfinavir inhibits CYP3A4 and this results in an increase of saquinavir concentrations. The AUC of saquinavir increases by 400% (soft gel) and from 400 to 1150% (hard gel).
The AUC of nelfinavir increases with 17%. (with soft gel)
Nelfinavir also decreases the elimination of saquinavir.
Recommendation Adjustment in dosage are necessary for Fortovase® (soft gel)
No adjustment of dosage necessary for Invirase® (hard gel)
References 135,156,142,143,158,131,133


Back to interaction table   Drug interactions between nelfinavir and stavudine
Interaction There is no clinically significant drug interaction.
Recommendation No specific action is required.
References 141,142,143


Back to interaction table   Drug interactions between nelfinavir and zalcitabine
Interaction There is no clinically significant drug interaction.
Recommendation No specific action is required.
References 143


Back to interaction table   Drug interactions between nelfinavir and zidovudine
Interaction The AUC and Cmax of zidovudine decreased by more than 35%, but this doesn't lead to a clinically significant drug interaction.
Recommendation No specific action is required.
References 135,142,143,131


Back to interaction table   Drug interactions between nevirapine and ritonavir
Interaction The AUC of ritonavir decreases by 11%, his Cmax by 11% and Cmin by 9%. This is result of the induction of the metabolisation of ritonavir by nevirapine. 
This doesn't lead to a clinically significant drug interaction.
Recommendation No specific action is required.
References 135,156,142,145


Back to interaction table   Drug interactions between nevirapine and saquinavir
Interaction Nevirapine induces CYP3A4 and this results in an 27% increase of the AUC of saquinavir.
Recommendation Adjustment in dosage are necessary (Increase the dose of saquinavir)
References 135,137


Back to interaction table   Drug interactions between nevirapine and stavudine
Interaction There is no clinically significant drug interaction.
Recommendation No specific action is required.
References 141,145


Back to interaction table   Drug interactions between nevirapine and zalcitabine
Interaction There is no clinically significant drug interaction.
Recommendation No adjustment of dosage necessary.
References 132


Back to interaction table   Drug interactions between nevirapine and zidovudine
Interaction There is no clinically significant drug interaction.
Recommendation No adjustment of dosage necessary.
References 145,146


Back to interaction table   Drug interactions between ritonavir and saquinavir
Interaction Ritonavir may inhibit the hepatic metabolism of saquinavir (CYP3A4). The AUC of saquinavir increases by more then 2000%.
The AUC and Cmax of ritonavir remains unchanged.
Recommendation Adjustment in dosage are necessary (Decrease the dose of ritonavir and saquinavir to 400mg 2x a day)
References 135,158,131,133,132,134,157,161,162,163


Back to interaction table   Drug interactions between ritonavir and stavudine
Interaction There is no clinically significant drug interaction.
Recommendation No specific action is required.
References 141


Back to interaction table   Drug interactions between ritonavir and zidovudine
Interaction Ritonavir may decrease the bioavailability of zidovudine, because it reduces the AUC of zidovudine by 25%. The clinical significance of this interaction is unknown.
Recommendation No adjustment of dosage should be necessary, but monitor the clinical efficacy of this combination and increase the dose of zidovudine if necessary.
References 135,147,148,131,132


Back to interaction table   Drug interactions between saquinavir and zalcitabine
Interaction There is no clinically significant drug interaction. Both drugs have different elimination routes.
Recommendation No specific action is required.
References 132


Back to interaction table   Drug interactions between saquinavir and zidovudine
Interaction There is no clinically significant drug interaction.
Recommendation No specific action is required.
References 132


Back to interaction table   Drug interactions between stavudine and zalcitabine
Interaction There is no clinically significant drug interaction.
Toxicity Concomitant use can lead to an increased risk of peripheral neuropathy. 
Recommendation No adjustment of dosage necessary, but monitor for signs and symptoms of peripheral neuropathy: numbness, burning dysesthesia and weakness involving the distal extremeties, tingling.
References 136,141,133,149,152,164


Back to interaction table   Drug interactions between stavudine and zidovudine
Interaction The phosphorylation of stavudine is decreased by zidovudine. 
Recommendation Concomitant use is dissuaded
References 136,164


Back to interaction table   Drug interactions between zalcitabine and zidovudine
Interaction There is no clinically significant drug interaction.
Recommendation No adjustment of dosage necessary.
References 147,138,,150,152,154,165
About this site Introduction to HIV Introduction to cytochrome P450 Treatment of HIV References Antiretroviral interaction table Useful links