Drug Interaction Report
3 potential interactions and/or warnings found for the following 2 drugs:
- Kaletra (lopinavir / ritonavir)
- medroxyprogesterone
Interactions between your drugs
medroxyPROGESTERone ritonavir
Applies to: medroxyprogesterone, Kaletra (lopinavir / ritonavir)
MONITOR: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations and pharmacologic effects of medroxyprogesterone, which is primarily metabolized by the isoenzyme. Aminoglutethimide, a CYP450 3A4 inducer, has been shown to significantly decrease the serum levels of medroxyprogesterone by 50% or more when administered at 250 mg two to four times daily to women with breast cancer receiving high-dose medroxyprogesterone orally. The decrease was accompanied by an increase in serum cortisol level, which suggests diminished adrenal suppressive effect of medroxyprogesterone. The interaction has not been studied with depot formulations of medroxyprogesterone. Because the clearance of medroxyprogesterone is approximately equal to the rate of hepatic blood flow, drugs that induce CYP450 3A4 are not expected to significantly affect the pharmacokinetics of medroxyprogesterone administered parenterally. In one study, no interaction was reported when medroxyprogesterone was administered intravenously with aminoglutethimide.
MANAGEMENT: Pharmacologic response to medroxyprogesterone should be monitored more closely whenever a CYP450 3A4 inducer is added to or withdrawn from therapy, and the dosage adjusted as necessary. When administered as the depot formulation for contraception, no dosage adjustment for medroxyprogesterone is currently recommended during coadministration with CYP450 3A4 inducers. However, consideration may be given to decreasing the dosing interval (e.g., from one injection every 12 weeks to every 10 weeks) if an interaction is suspected.
References
- Lundgren S, Lonning PE, Aakvaag A, Kvinnsland S, Lnning PE (1990) "Influence of aminoglutethimide on the metabolism of medroxyprogesterone acetate and megestrol acetate in postmenopausal patients with advanced breast cancer." Cancer Chemother Pharmacol, 27, p. 101-5
- Halpenny O, Bye A, Cranny A, Feely J, Daly PA (1990) "Influence of aminoglutethimide on plasma levels of medroxyprogesterone acetate." Med Oncol Tumor Pharmacother, 7, p. 241-7
- (2001) "Product Information. Depo-Provera (medroxyprogesterone)." Pharmacia and Upjohn
- (2001) "Product Information. Provera (medroxyprogesterone)." Pharmacia and Upjohn
- Kobayashi K, Mimura N, Fujii H, et al. (2000) "Role of human cytochrome P450 3A4 in metabolism of medroxyprogesterone acetate." Clin Cancer Res, 6, p. 3297-303
- (2005) "FFPRHC Guidance (April 2005). Drug interactions with hormonal contraception." J Fam Plann Reprod Health Care, 31, p. 139-51
- O'Brien MD, Guillebaud J (2006) "Contraception for women with epilepsy." Epilepsia, 47, p. 1419-22
Drug and food interactions
ritonavir food
Applies to: Kaletra (lopinavir / ritonavir)
ADJUST DOSING INTERVAL: Administration with food may modestly affect the bioavailability of ritonavir from the various available formulations. When the oral solution was given under nonfasting conditions, peak ritonavir concentrations decreased 23% and the extent of absorption decreased 7% relative to fasting conditions. Dilution of the oral solution (within one hour of dosing) with 240 mL of chocolate milk or a nutritional supplement (Advera or Ensure) did not significantly affect the extent and rate of ritonavir absorption. When a single 100 mg dose of the tablet was administered with a high-fat meal (907 kcal; 52% fat, 15% protein, 33% carbohydrates), approximately 20% decreases in mean peak concentration (Cmax) and systemic exposure (AUC) were observed relative to administration after fasting. Similar decreases in Cmax and AUC were reported when the tablet was administered with a moderate-fat meal. In contrast, the extent of absorption of ritonavir from the soft gelatin capsule formulation was 13% higher when administered with a meal (615 KCal; 14.5% fat, 9% protein, and 76% carbohydrate) relative to fasting.
MANAGEMENT: Ritonavir should be taken with meals to enhance gastrointestinal tolerability.
References
- (2001) "Product Information. Norvir (ritonavir)." Abbott Pharmaceutical
lopinavir food
Applies to: Kaletra (lopinavir / ritonavir)
ADJUST DOSING INTERVAL: Food significantly increases the bioavailability of lopinavir from the oral solution formulation of lopinavir-ritonavir. Relative to fasting, administration of lopinavir-ritonavir oral solution with a moderate-fat meal (500 to 682 Kcal; 23% to 25% calories from fat) increased lopinavir peak plasma concentration (Cmax) and systemic exposure (AUC) by 54% and 80%, respectively, whereas administration with a high-fat meal (872 Kcal; 56% from fat) increased lopinavir Cmax and AUC by 56% and 130%, respectively. No clinically significant changes in Cmax and AUC were observed following administration of lopinavir-ritonavir tablets under fed conditions versus fasted conditions. Relative to fasting, administration of a single 400 mg-100 mg dose (two 200 mg-50 mg tablets) with a moderate-fat meal (558 Kcal; 24.1% calories from fat) increased lopinavir Cmax and AUC by 17.6% and 26.9%, respectively, while administration with a high-fat meal (998 Kcal; 51.3% from fat) increased lopinavir AUC by 18.9% but not Cmax. Relative to fasting, ritonavir Cmax and AUC also increased by 4.9% and 14.9%, respectively, with the moderate-fat meal and 10.3% and 23.9%, respectively, with the high-fat meal.
MANAGEMENT: Lopinavir-ritonavir oral solution should be taken with meals to enhance bioavailability and minimize pharmacokinetic variability. Lopinavir-ritonavir tablets may be taken without regard to meals.
References
- (2001) "Product Information. Kaletra (lopinavir-ritonavir)." Abbott Pharmaceutical
Therapeutic duplication warnings
No duplication 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.
Drug Interaction Classification
Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. | |
Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. | |
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. | |
No interaction information available. |
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