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Drug Interactions between artemether / lumefantrine and emtricitabine / nelfinavir / tenofovir

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Major

nelfinavir artemether

Applies to: emtricitabine / nelfinavir / tenofovir and artemether / lumefantrine

MONITOR CLOSELY: Coadministration with potent inhibitors of CYP450 3A4 may increase the plasma concentrations of artemether and lumefantrine, both of which are primarily metabolized by the isoenzyme. In 13 healthy subjects, concurrent oral administration of the potent inhibitor ketoconazole (400 mg on day 1, followed by 200 mg for 4 days) and a single dose of artemether-lumefantrine (80 mg-480 mg) with food resulted in modest increases in systemic exposure (AUC) to artemether (2.3-fold), its active metabolite dihydroartemisinin (1.5-fold), and lumefantrine (1.6-fold). High plasma levels of artemether and lumefantrine may theoretically increase the risk of QT interval prolongation and ventricular arrhythmias including torsade de pointes. In clinical trials, asymptomatic prolongation of the Fridericia-corrected QT interval (QTcF) by more than 30 msec from baseline was reported in approximately one-third of patients treated with artemether-lumefantrine, and prolongation by more than 60 msec was reported in more than 5% of patients. A few patients (0.4%) in the adult/adolescent population and no patient in the infant/children population experienced a QTcF greater than 500 msec. However, the possibility that these increases were disease-related cannot be ruled out. In a study of healthy adult volunteers, administration of the six-dose regimen of artemether-lumefantrine was associated with mean changes in QTcF from baseline of 7.45, 7.29, 6.12 and 6.84 msec at 68, 72, 96, and 108 hours after the first dose, respectively. There was a concentration-dependent increase in QTcF for lumefantrine. No subject had a greater than 30 msec increase from baseline nor an absolute increase to more than 500 msec.

MONITOR CLOSELY: Coadministration with artemether may decrease the plasma concentrations of CYP450 3A4 substrates such as protease inhibitors, macrolide antibiotics, and azole antifungal agents. In vitro and human studies have demonstrated that artemisinins including artemether have some capacity to induce CYP450 3A4. The clinical significance is unknown.

MANAGEMENT: No dose adjustment of artemether-lumefantrine is necessary when administered in combination with potent CYP450 3A4 inhibitors such as azole antifungal agents, nefazodone, delavirdine, protease inhibitors, and ketolide and certain macrolide antibiotics. However, caution is advised due to increased risk of QT interval prolongation. Patients should be advised to seek medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, palpitations, or syncope. Patients should also be monitored for reduced effects or potential loss of efficacy of the concomitant drug(s), especially antiretroviral agents.

References

  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. Cerner Multum, Inc. "Australian Product Information."
  3. (2009) "Product Information. Coartem (artemether-lumefantrine)." Novartis Pharmaceuticals

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Major

nelfinavir lumefantrine

Applies to: emtricitabine / nelfinavir / tenofovir and artemether / lumefantrine

MONITOR CLOSELY: Coadministration with potent inhibitors of CYP450 3A4 may increase the plasma concentrations of artemether and lumefantrine, both of which are primarily metabolized by the isoenzyme. In 13 healthy subjects, concurrent oral administration of the potent inhibitor ketoconazole (400 mg on day 1, followed by 200 mg for 4 days) and a single dose of artemether-lumefantrine (80 mg-480 mg) with food resulted in modest increases in systemic exposure (AUC) to artemether (2.3-fold), its active metabolite dihydroartemisinin (1.5-fold), and lumefantrine (1.6-fold). High plasma levels of artemether and lumefantrine may theoretically increase the risk of QT interval prolongation and ventricular arrhythmias including torsade de pointes. In clinical trials, asymptomatic prolongation of the Fridericia-corrected QT interval (QTcF) by more than 30 msec from baseline was reported in approximately one-third of patients treated with artemether-lumefantrine, and prolongation by more than 60 msec was reported in more than 5% of patients. A few patients (0.4%) in the adult/adolescent population and no patient in the infant/children population experienced a QTcF greater than 500 msec. However, the possibility that these increases were disease-related cannot be ruled out. In a study of healthy adult volunteers, administration of the six-dose regimen of artemether-lumefantrine was associated with mean changes in QTcF from baseline of 7.45, 7.29, 6.12 and 6.84 msec at 68, 72, 96, and 108 hours after the first dose, respectively. There was a concentration-dependent increase in QTcF for lumefantrine. No subject had a greater than 30 msec increase from baseline nor an absolute increase to more than 500 msec.

MONITOR CLOSELY: Coadministration with artemether may decrease the plasma concentrations of CYP450 3A4 substrates such as protease inhibitors, macrolide antibiotics, and azole antifungal agents. In vitro and human studies have demonstrated that artemisinins including artemether have some capacity to induce CYP450 3A4. The clinical significance is unknown.

MANAGEMENT: No dose adjustment of artemether-lumefantrine is necessary when administered in combination with potent CYP450 3A4 inhibitors such as azole antifungal agents, nefazodone, delavirdine, protease inhibitors, and ketolide and certain macrolide antibiotics. However, caution is advised due to increased risk of QT interval prolongation. Patients should be advised to seek medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, palpitations, or syncope. Patients should also be monitored for reduced effects or potential loss of efficacy of the concomitant drug(s), especially antiretroviral agents.

References

  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. Cerner Multum, Inc. "Australian Product Information."
  3. (2009) "Product Information. Coartem (artemether-lumefantrine)." Novartis Pharmaceuticals

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Drug and food interactions

Moderate

lumefantrine food

Applies to: artemether / lumefantrine

GENERALLY AVOID: Coadministration with grapefruit juice may increase the plasma concentrations of artemether and lumefantrine. The mechanism is decreased clearance due to inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. High plasma levels of artemether and lumefantrine may increase the risk of QT interval prolongation and ventricular arrhythmias including torsade de pointes. In clinical trials, asymptomatic prolongation of the Fridericia-corrected QT interval (QTcF) by more than 30 msec from baseline was reported in approximately one-third of patients treated with artemether-lumefantrine, and prolongation by more than 60 msec was reported in more than 5% of patients. A few patients (0.4%) in the adult/adolescent population and no patient in the infant/children population experienced a QTcF greater than 500 msec. However, the possibility that these increases were disease-related cannot be ruled out. In a study of healthy adult volunteers, administration of the six-dose regimen of artemether-lumefantrine was associated with mean changes in QTcF from baseline of 7.45, 7.29, 6.12 and 6.84 msec at 68, 72, 96, and 108 hours after the first dose, respectively. There was a concentration-dependent increase in QTcF for lumefantrine. No subject had a greater than 30 msec increase from baseline nor an absolute increase to more than 500 msec.

ADJUST DOSING INTERVAL: Food enhances the oral absorption of artemether and lumefantrine. In healthy volunteers, the relative bioavailability of artemether increased by two- to threefold and that of lumefantrine by sixteenfold when administered after a high-fat meal as opposed to under fasted conditions.

MANAGEMENT: Patients receiving artemether-lumefantrine therapy should avoid the consumption of grapefruits and grapefruit juice. To ensure maximal oral absorption, artemether-lumefantrine should be taken with food. Inadequate food intake can increase the risk for recrudescence of malaria. Patients who are averse to food during treatment should be closely monitored and encouraged to resume normal eating as soon as food can be tolerated.

References

  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. Cerner Multum, Inc. "Australian Product Information."
  3. (2009) "Product Information. Coartem (artemether-lumefantrine)." Novartis Pharmaceuticals

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Minor

tenofovir food

Applies to: emtricitabine / nelfinavir / tenofovir

Food enhances the oral absorption and bioavailability of tenofovir, the active entity of tenofovir disoproxil fumarate. According to the product labeling, administration of the drug following a high-fat meal increased the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of tenofovir by approximately 14% and 40%, respectively, compared to administration in the fasting state. However, administration with a light meal did not significantly affect the pharmacokinetics of tenofovir compared to administration in the fasting state. Food delays the time to reach tenofovir Cmax by approximately 1 hour. Tenofovir disoproxil fumarate may be administered without regard to meals.

References

  1. (2001) "Product Information. Viread (tenofovir)." Gilead Sciences

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Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.


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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.