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Drug Interactions between conjugated estrogens / medroxyprogesterone and deferasirox

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

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Interactions between your drugs

Moderate

medroxyPROGESTERone deferasirox

Applies to: conjugated estrogens / medroxyprogesterone and deferasirox

ADDITIONAL CONTRACEPTION RECOMMENDED: Coadministration with deferasirox may decrease the plasma concentrations of contraceptive hormones. The proposed mechanism is deferasirox induction of CYP450 3A4, the isoenzyme primarily responsible for the metabolic clearance of sex hormones.

MANAGEMENT: Hormonal contraceptives agents may not be reliable when used with deferasirox. Female patients of reproductive potential receiving hormonal contraceptives should be counseled to use alternative or additional methods of birth control during treatment with deferasirox.

References (1)
  1. (2001) "Product Information. Desferal (deferoxamine)." Novartis Pharmaceuticals
Moderate

conjugated estrogens deferasirox

Applies to: conjugated estrogens / medroxyprogesterone and deferasirox

MONITOR: Coadministration with deferasirox may decrease the plasma concentrations of drugs that are substrates of the CYP450 3A4 isoenzyme. The mechanism may involve induction of CYP450 3A4 activity by deferasirox, although in vitro, the drug has been shown to inhibit CYP450 3A4. In healthy volunteers, administration of the CYP450 3A4 probe substrate midazolam in combination with deferasirox resulted in a reduction of midazolam peak concentration by 23% and systemic exposure by 17%. In the clinical setting, this effect may be more pronounced.

MANAGEMENT: Caution is advised if deferasirox must be used concomitantly with medications that undergo metabolism by CYP450 3A4, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever deferasirox is added to or withdrawn from therapy.

References (2)
  1. (2005) "Product Information. Exjade (deferasirox)." Novartis Pharmaceuticals
  2. Skerjanec A, Wang J, Maren K, Rojkjaer L (2010) "Investigation of the pharmacokinetic interactions of deferasirox, a once-daily oral iron chelator, with midazolam, rifampin, and repaglinide in healthy volunteers." J Clin Pharmacol, 50, p. 205-13

Drug and food interactions

Moderate

deferasirox food

Applies to: deferasirox

ADJUST DOSING INTERVAL: According to product labeling, the bioavailability of deferasirox was variably increased when taken with a meal.

MANAGEMENT: To ensure consistent plasma drug levels, deferasirox should be taken on an empty stomach 30 minutes before eating preferably at the same time everyday.

References (1)
  1. (2005) "Product Information. Exjade (deferasirox)." Novartis Pharmaceuticals
Minor

conjugated estrogens food

Applies to: conjugated estrogens / medroxyprogesterone

Coadministration with grapefruit juice may increase the bioavailability of oral estrogens. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits. In a small, randomized, crossover study, the administration of ethinyl estradiol with grapefruit juice (compared to herbal tea) increased peak plasma drug concentration (Cmax) by 37% and area under the concentration-time curve (AUC) by 28%. Based on these findings, grapefruit juice is unlikely to affect the overall safety profile of ethinyl estradiol. However, as with other drug interactions involving grapefruit juice, the pharmacokinetic alterations are subject to a high degree of interpatient variability. Also, the effect on other estrogens has not been studied.

References (2)
  1. Weber A, Jager R, Borner A, et al. (1996) "Can grapefruit juice influence ethinyl estradiol bioavailability?" Contraception, 53, p. 41-7
  2. Schubert W, Eriksson U, Edgar B, Cullberg G, Hedner T (1995) "Flavonoids in grapefruit juice inhibit the in vitro hepatic metabolism of 17B-estradiol." Eur J Drug Metab Pharmacokinet, 20, p. 219-24

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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