Drug Interaction Report

Caffeine may interfere with the effects of dipyridamole in dilating the arteries. You should avoid caffeine-containing products for at least 24 hours before an imaging procedure involving dipyridamole given by injection. However, no special precaution is necessary if you are taking dipyridamole orally for maintenance.

Grapefruit juice may increase the blood levels of certain medications such as levonorgestrel. You may want to limit your consumption of grapefruit and grapefruit juice during treatment with levonorgestrel. 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.

Ask your doctor before using dipyridamole together with caffeine. Using these medications together can decrease the effects of dipyridamole. It is recommended that caffeine including caffeine be avoided for 12 to 24 hours before dipyridamole administration. You may need a dose adjustment or special test if you use both medications. 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.

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.