Zolmitriptan

7 DRUG INTERACTIONS

7.1 Ergot-containing Drugs Ergot-containing drugs have been reported to cause prolonged vasospastic reactions. Because these effects may be additive, use of ergotamine-containing or ergot-type medications (like dihydroergotamine or methysergide) and zolmitriptan within 24 hours of each other is contraindicated [see Contraindications ( 4 ) ].

7.2 MAO-A Inhibitors MAO-A inhibitors increase the systemic exposure of zolmitriptan and its active N-desmethyl metabolite. Therefore, the use of zolmitriptan in patients receiving MAO-A inhibitors is contraindicated [see Contraindications ( 4 ) and Clinical Pharmacology ( 12.3 ) ] . 7.3 5-HT 1B/1D agonists Concomitant use of other 5-HT 1B/1D agonists (including triptans) within 24 hours of zolmitriptan treatment is contraindicated because the risk of vasospastic reactions may be additive [see Contraindications ( 4 ) ].

7.4 Selective Serotonin Reuptake Inhibitors and Serotonin Norepinephrine Reuptake Inhibitors Cases of life-threatening serotonin syndrome have been reported during co-administration of triptans and selective serotonin reuptake inhibitors (SSRIs) or serotonin norepinephrine reuptake inhibitors (SNRIs) [see Warnings and Precautions ( 5.7 ) ].

7.5 Cimetidine Following administration of cimetidine, the half-life and blood levels of zolmitriptan and its active N-desmethyl metabolite were approximately doubled [see Clinical Pharmacology ( 12.3 ) ] . If cimetidine and zolmitriptan are used concomitantly, limit the maximum single dose of zolmitriptan to 2.5 mg, not to exceed 5 mg in any 24-hour period [see Dosage and Administration, ( 2.4 ) and Clinical Pharmacology ( 12.3 ) ].

8.1 Pregnancy Risk Summary There are no adequate data on the developmental risk associated with the use of zolmitriptan in pregnant women. In reproductive toxicity studies in rats and rabbits, oral administration of zolmitriptan to pregnant animals resulted in embryolethality and fetal abnormalities (malformations and variations) at clinically relevant exposures (see Data). In the U.S general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4%, and 15% to 20%, respectively.

The estimated rates of major birth defects (2.2% to 2.9%) and miscarriage (17%) among deliveries to women with migraine are similar to rates reported in women without migraine. Clinical Considerations Disease-Associated Maternal and/or Embryo/Fetal Risk Published data have suggested that women with migraine may be at increased risk of preeclampsia during pregnancy. Data Animal Data When zolmitriptan was administered to pregnant rats during the period of organogenesis at oral doses of 100, 400, and 1200 mg/kg/day (plasma exposures (AUCs) ≈280, 1100, and 5000 times the human AUC at the maximum recommended human dose (MRHD) of 10 mg/day), there was a dose-related increase in embryolethality.

A no-effect dose for embryolethality was not established. When zolmitriptan was administered to pregnant rabbits during the period of organogenesis at oral doses of 3, 10, and 30 mg/kg/day (plasma AUCs ≈1, 11, and 42 times the human AUC at the MRHD), there were increases in embryolethality and in fetal malformations and variations. The no-effect dose for adverse effects on embryofetal development was associated with a plasma AUC similar to that in humans at the MRHD.

When female rats were given zolmitriptan during gestation, parturition, and lactation at oral doses of 25, 100, and 400 mg/kg/day (plasma AUCs ≈70, 280, and 1100 times that in human at the MRHD), an increased incidence of hydronephrosis was found in the offspring. The no-effect dose was associated with a plasma AUC ≈280 times that in humans at the MRHD.