Lack of Interaction Between Pizotifen and the Novel Antimigraine Compound Zolmitriptan in Healthy Volunteers

Summary

This double-blind, randomised, two-period crossover study investigated the effect of pizotifen on the pharmacokinetics and tolerability profile of zolmitriptan (formerly 311C90), a novel selective 5-HT_1D receptor agonist for acute migraine therapy. 13 healthy volunteers (mean age 31 years, range 19 to 41 years; mean weight 75kg, range 62 to 89kg) received oral pizotifen 1.5mg or placebo once daily for 8 days with a washout period of at least 2 weeks between study periods. Oral zolmitriptan 10mg was administered with the final dose of pizotifen or placebo. Pizotifen did not significantly affect the pharmacokinetic parameters of zolmitriptan, although in 4 subjects the time to peak plasma zolmitriptan concentration (t_max) was increased in the presence of pizotifen (median increase 1.4 hours). Zolmitriptan caused a small, transient, clinically insignificant increase in blood pressure, which was not affected by pizotifen. No clinically relevant changes in heart rate or 12-lead ECGs were observed. One volunteer was withdrawn because of a brief, 5-beat run, asymptomatic episode of ventricular tachycardia 170 minutes after administration with zolmitriptan plus placebo; this was not considered related to the treatment. Zolmitriptan was well tolerated both alone and in combination with pizotifen. Thus, there is no contraindication to the use of zolmitriptan nor a need for dosage modification in patients concomitantly receiving pizotifen.