Safety,Tolerability,and Pharmacokinetics of Sumatriptan in Healthy Subjects Following Ascending Single Intranasal Doses and Multiple Intranasal Doses

The delivery of sumatriptan doses intranasally could add greater flexibility in the treatment of migraine than is possible with the currently available subcutaneous and oral sumatriptan preparations. Two independent double-blind, randomized, placebo-controlled clinical studies were conducted to evaluate the safety, tolerability and pharmacokinetics of intranasally administered sumatriptan following ascending single doses (three different dose levels) and multiple doses. In the four-way crossover, ascending-dose study, 20 healthy female subjects were randomized to receive on separate occasions single intranasal spray doses of 5, 10, or 20 mg sumatriptan (as the hemisulphate salt) or placebo into one nostril. Adverse events were mild and consisted mainly of bitter taste at the back of the throat and events typical of sumatriptan administered by other routes (headache, lightheadedness and tingling). Area under the plasma sumatriptan concentration versus time curve (AUC) and peak plasma concentration (C_max) increased with the dose. Dose proportionality was demonstrated between 5 and 10 mg but not across the dose range 5–20 mg. Time to maximum plasma concentration (t_max) was variable due to multiple peaking. The elimination half-life (t_1/2), approximately 2 h, was unaffected by the magnitude of dose. In the two-period, multiple-dose, crossover study, 12 healthy adult male and female subjects were randomized to receive either sumatriptan hemisulphate 20 mg or placebo, administered intranasally as a spray three times a day for 4 days, The two dosing periods were separated by 3 to 14 days. Multiple doses of sumatriptan were well tolerated, with no serious adverse events occurring or withdrawals due to adverse events. All patients reported a mild to moderate drug-related disturbance of taste. Nasal examinations remained normal, and olfactory function was unaffected. The AUC over the first 8 h following dosing (AUC₈) and fraction of the dose excreted in the urine (f_e; 6.2% vs 3.6%) were similar on Days 1 and 4. Day 4 values were significantly higher (p0.05) for C_max (16.9 ng/ml vs 13.1 ng/ml), renal clearance (Cl_r; 19.0 l/h vs 14.2 l/h), and t_1/2 (2.18 h vs 1.93 h), and shorter for t_max (0.88 h vs 1.75 h). Some accumulation (22%) occurred over the 4 days of dosing. Serum concentrations of the pharmacologically inactive indole acetic acid metabolite of sumatriptan were fourfold to fivefold higher than corresponding sumatriptan concentrations. Overall, these studies show the sumatriptan intranasal spray formulation is well tolerated, allows rapid absorption of sumatriptan, and results in only a clinically insignificant degree of sumatriptan accumulation upon repeated dosing.