Drug Interaction Report

Asparaginase Erwinia chrysanthemi may reduce the blood levels and effects of ethinyl estradiol. If you are using ethinyl estradiol for birth control, you may be at increased risk for pregnancy or breakthrough bleeding. Your doctor may prescribe you an alternative method of birth control during and for some time after treatment with asparaginase Erwinia chrysanthemi. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Asparaginase Erwinia chrysanthemi may reduce the blood levels and effects of norethindrone. If you are using norethindrone for birth control, you may be at increased risk for pregnancy or breakthrough bleeding. Your doctor may prescribe you an alternative method of birth control during and for some time after treatment with asparaginase Erwinia chrysanthemi. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Grapefruit juice may increase the blood levels of certain medications such as norethindrone. You may want to limit your consumption of grapefruit and grapefruit juice during treatment with norethindrone. However, if you have been regularly consuming grapefruit or grapefruit juice with the medication, then it is advisable for you to talk with your doctor before changing the amounts of these products in your diet, as this may alter the effects of your medication. Contact your doctor if your condition changes or you experience increased side effects. Orange juice is not expected to interact.

Consumer information for this interaction is not currently available.

MONITOR: Coadministration of ethinyl estradiol may increase the plasma concentrations of drugs that are primarily metabolized by CYP450 1A2. In a study of 30 healthy volunteers administered the CYP450 1A2 substrate tizanidine, the systemic exposure (AUC) of tizanidine was 3.9 times greater in women using an oral contraceptive containing ethinyl estradiol.

MANAGEMENT: Patients should be monitored for increased adverse effects of the CYP450 1A2 substrate during concomitant use with ethinyl estradiol. Product labeling for the specific CYP450 1A2 substrate should be consulted for additional recommendations.

Information for this minor interaction is available on the professional version.

Information for this minor interaction is available on the professional version.

Information for this minor interaction is available on the professional version.