Pharmacokinetics of sumatriptan nasal spray in adolescents

Sumatriptan is a potent and selective vascular 5-HT1 receptor agonist effective for the treatment of migraine. In adults, intranasal sumatriptan is well absorbed and tolerated. The authors evaluated the pharmacokinetics and tolerability of a single dose of 20 mg intranasal sumatriptan in healthy adolescent migraineurs ages 12 to 17 years, administered outside of migraine attack. Serum sumatriptan levels were measured by high-performance liquid chromatography (HPLC) with electrochemical detection in serial samples collected over 8 hours. Physical exam, vital signs, clinical laboratory tests, and electrocardiogram measurements were monitored to assess safety and tolerability. A total of 16 subjects (10 males and 6 females) had pharmacokinetic data that could be analyzed, 2 withdrew from the study 30 and 60 minutes after dosing following the loss of venous access for blood sampling, and a bioanalysis failure resulted in loss of data from 3 subjects. Noncompartmental pharmacokinetic parameters (geometric mean and 95% confidence interval) for the remaining 16 subjects were as follows: Cmax was 13.9 (11.0, 17.6) ng/mL, AUC infinity was 57.3 (47.6, 69.0) ng/mL.h, and t1/2 was 2.0 (1.8, 2.3) hours. Population pharmacokinetic analysis for all subjects (n = 21) showed that clearance and volume of distribution increase slightly with age and body size, but the changes were minimal and would not warrant dose adjustment: CL/F was 316 L (coefficient of variance [CV] = 25%) and Vd/F was 1070 L (CV = 46%). Sumatriptan was well tolerated with only minor adverse events reported, which all resolved spontaneously. The pharmacokinetic parameters in these adolescent subjects were similar to those previously reported in adults, suggesting that adolescents should be dosed similar to adults.