Zolmitriptan Cimetidine

A two-period crossover, double-blind study in 20 subjects given fluoxetine 20 mg or a placebo daily for 28 days, with zolmitriptan 10 mg on day 28, found that the pharmacokinetics of zolmitriptan were unaffected by fluoxetine. Only very slight changes were seen in the pharmacokinetics of its active metabolite. Sertraline, paroxetine, and citalopram are also not expected to alter the pharmacokinetics of zolmitriptan. However, fluvoxamine, a CYP1A2 inhibitor, is predicted to increase levels of zolmitriptan, based on the known interaction with cimetidine (see Triptans Zolmitriptan + Cimetidine , p.608). 

Uses Obesity Action Blocks uptake of norepinephrine, serotonin, dopamine Dose 10 mg/d PO, may to 5 mg after 4 wk Caution [C, -] w/ SSRIs, Li, dextromethorphan, opioids Contra MAOI w/in 14 d, uncontrolled HTN, arrhythmias Disp Caps SE HA, insomnia, xerostomia, constipation, rhinitis, tach, HTN Interactions T Risk of serotonin synd W/ dextromethorphan, ergots, fentanyl, Li, meperidine, MAOIs, naratriptan, pentazocine, rizatriptan, sumatriptan, SSRIs, tryptophan, zolmitriptan, St. John s wort effects W/ cimetidine, erythromycin, ketoconazole T CNS depression W/ EtOH EMS Use fentanyl w/ caution, may T risk of serotonin synd concurrent EtOH use can T CNS depression OD May cause tach, HTN, diaphoresis, HA, fever, agitation, muscle tremors, and Szs symptomatic and supportive... 

ALMOTRIPTAN, ELETRIPTAN, ZOLMITRIPTAN H2-RECEPT0R BLOCKERS -CIMETIDINE t efficacy and adverse effects of zolmitriptan, e.g. flushing, sensations of tingling, heat, heaviness, pressure or tightness of any part of body including the throat and chest, dizziness Inhibition of metabolism via CYP1A2 Consider alternative acid suppression, e.g. H2 antagonist or proton pump inhibitors (not omeprazole or lansoprazole), or monitor more closely and l maximum dose of zolmitriptan to 5 mg/24 hours... 

The manufacturer of zolmitriptan notes that the half-life of zolmitriptan was increased by 44% and the AUC by 48% when it was given after the use of cimetidine. They suggest that this may be because of the inhibitory effect of cimetidine on the cytochrome P450 isoenzyme CYP1A2, an enzyme involved in the metabolism of zolmitriptan. The UK manufacturer recommends a zolmitriptan dose reduction to a maximum of 5 mg in 24 hours in patients taking cimetidine. The US manufacturer makes no recommendation on dose. ... 

---