A double-blind, placebo-controlled evaluation of the effect of oral doses of rizatriptan 10 mg on oral contraceptive pharmacokinetics in healthy female volunteers

Rizatriptan (MAXALT), a potent, oral 5-HT1B/1D agonist with a rapid onset of action, is available now for the acute treatment of migraine. This study examined the pharmacokinetic and clinical interaction between rizatriptan 10 mg and the components (ethinyl estradiol [EE] 35 micrograms and norethindrone [NET] 1.0 mg) of a well-established oral contraceptive combination product, ORTHO-NOVUM 1/35. Levels of sex hormone binding globulin (SHBG), a protein increased by EE to which NET binds, were also examined. In this two-period crossover study, 20 healthy young female subjects received a coadministration of 8 days of rizatriptan treatment (6 days of single-dose 10 mg rizatriptan and 2 days of multiple-dose rizatriptan, 10 mg q 4 hours for three doses, giving a total daily dose of 30 mg on Days 7 and 8) or matching placebo along with their daily dose (one tablet) of ORTHO-NOVUM 1/35 within their oral contraceptive cycle. Plasma was sampled for EE, NET, and SHBG concentrations. Safety evaluations included routine laboratory safety studies, physical examinations, and monitoring for ECG, vital signs, and adverse events. There were no statistically significant differences in any of the pharmacokinetic parameters of EE or NET between the rizatriptan and placebo treatment periods, thus indicating that rizatriptan had no meaningful effect on the disposition of either the EE or the NET component of ORTHO-NOVUM 1/35. The SHBG concentration did not change throughout the entire study. Clinically, coadministration of rizatriptan with ORTHO-NOVUM 1/35 was well tolerated. Blood pressure, heart rate, and temperature showed no consistent trend or clinically important changes. Adverse events following coadministration of rizatriptan with ORTHO-NOVUM 1/35 were similar to those reported when placebo was given with ORTHO-NOVUM 1/35. The findings of this study indicate that there is little potential for dosages as high as 30 mg/day, the maximum recommended dosing schedule, of rizatriptan to alter the plasma concentrations of oral contraceptives.
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