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Drug Interactions between atazanavir and E S P

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

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Interactions between your drugs

Moderate

erythromycin atazanavir

Applies to: E S P (erythromycin / sulfisoxazole) and atazanavir

MONITOR: Coadministration of a macrolide antibiotic, such as clarithromycin or erythromycin, with atazanavir and/or cobicistat may increase the plasma concentrations of all the drugs involved. The mechanism may involve both competitive and noncompetitive inhibition of CYP450 3A4, since these drugs are all substrates as well as inhibitors of the isoenzyme. Clinically elevated plasma levels of clarithromycin or erythromycin may increase the risk of QT interval prolongation and torsade de pointes. In a population-based retrospective study of 1476 cases of confirmed sudden death from cardiac causes, concurrent use of erythromycin and a CYP450 3A4 inhibitor was associated with a marked increase in the risk of sudden death from cardiac causes.

MANAGEMENT: Alternative antibiotics should be considered. If clarithromycin or erythromycin is used in combination with atazanavir and/or cobicistat, caution and close clinical monitoring are recommended. Patients should be advised to seek medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitations, irregular heartbeat, shortness of breath, or syncope. For clarithromycin, a dosage reduction by 50% is recommended in patients with CrCl between 50 and 60 mL/min. No dosage adjustment is needed in patients with CrCl at or above 60 mL/min. Some authorities recommend avoiding the use of the fixed combination atazanavir-cobicistat with a macrolide antibiotic.

References

  1. (2003) "Product Information. Reyataz (atazanavir)." Bristol-Myers Squibb
  2. Iannini PB (2002) "Cardiotoxicity of macrolides, ketolides and fluoroquinolones that prolong the QTc interval." Expert Opin Drug Saf, 1, p. 121-8
  3. Ray WA, Murray KT, Meredith S, Narasimhulu SS, Hall K, Stein CM (2004) "Oral erythromycin and the risk of sudden death from cardiac causes." N Engl J Med, 351, p. 1089-96
  4. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  5. Cerner Multum, Inc. "Australian Product Information."
  6. (2012) "Product Information. Stribild (cobicistat/elvitegravir/emtricitabine/tenofov)." Gilead Sciences
  7. (2015) "Product Information. Evotaz (atazanavir-cobicistat)." Bristol-Myers Squibb
View all 7 references

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Drug and food interactions

Moderate

erythromycin food

Applies to: E S P (erythromycin / sulfisoxazole)

ADJUST DOSING INTERVAL: Food may variably affect the bioavailability of different oral formulations and salt forms of erythromycin. The individual product package labeling should be consulted regarding the appropriate time of administration in relation to food ingestion. Grapefruit juice may increase the plasma concentrations of orally administered erythromycin. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. In an open-label, crossover study consisting of six healthy subjects, the coadministration with double-strength grapefruit juice increased the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of a single dose of erythromycin (400 mg) by 52% and 49%, respectively, compared to water. The half-life was not affected. The clinical significance of this potential interaction is unknown.

MANAGEMENT: In general, optimal serum levels are achieved when erythromycin is taken in the fasting state, one-half to two hours before meals. However, some erythromycin products may be taken without regard to meals.

References

  1. Welling PG, Huang H, Hewitt PF, Lyons LL (1978) "Bioavailability of erythromycin stearate: influence of food and fluid volume." J Pharm Sci, 67, p. 764-6
  2. Welling PG, Elliott RL, Pitterle ME, et al. (1979) "Plasma levels following single and repeated doses of erythromycin estolate and erythromycin stearate." J Pharm Sci, 68, p. 150-5
  3. Welling PG (1977) "Influence of food and diet on gastrointestinal drug absorption: a review." J Pharmacokinet Biopharm, 5, p. 291-334
  4. Coyne TC, Shum S, Chun AH, Jeansonne L, Shirkey HC (1978) "Bioavailability of erythromycin ethylsuccinate in pediatric patients." J Clin Pharmacol, 18, p. 194-202
  5. Malmborg AS (1979) "Effect of food on absorption of erythromycin. A study of two derivatives, the stearate and the base." J Antimicrob Chemother, 5, p. 591-9
  6. Randinitis EJ, Sedman AJ, Welling PG, Kinkel AW (1989) "Effect of a high-fat meal on the bioavailability of a polymer-coated erythromycin particle tablet formulation." J Clin Pharmacol, 29, p. 79-84
  7. Kanazawa S, Ohkubo T, Sugawara K (2001) "The effects of grapefruit juice on the pharmacokinetics of erythromycin." Eur J Clin Pharmacol, 56, p. 799-803
View all 7 references

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Moderate

atazanavir food

Applies to: atazanavir

ADJUST DOSING INTERVAL: Administration of atazanavir with food enhances oral bioavailability and reduces pharmacokinetic variability. According to the manufacturer, administration with a light meal increased the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of a single 400 mg dose of atazanavir by 57% and 70%, respectively, relative to the fasting state. Administration with a high-fat meal resulted in a mean increase of 35% in atazanavir AUC and no change in Cmax compared to fasting. The coefficient of variation of AUC and Cmax decreased by approximately one-half when given with either a light or high-fat meal compared to the fasting state.

MANAGEMENT: To ensure maximal oral absorption, atazanavir should be administered with or immediately after a meal.

References

  1. (2003) "Product Information. Reyataz (atazanavir)." Bristol-Myers Squibb

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Minor

erythromycin food

Applies to: E S P (erythromycin / sulfisoxazole)

Ethanol, when combined with erythromycin, may delay absorption and therefore the clinical effects of the antibiotic. The mechanism appears to be due to slowed gastric emptying by ethanol. Data is available only for erythromycin ethylsuccinate. Patients should be advised to avoid ethanol while taking erythromycin salts.

References

  1. Morasso MI, Chavez J, Gai MN, Arancibia A (1990) "Influence of alcohol consumption on erythromycin ethylsuccinate kinetics." Int J Clin Pharmacol, 28, p. 426-9

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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.

See also

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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.

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