Pharmacokinetics of sumatriptan nasal spray in children.

The authors studied the pharmacokinetics of sumatriptan nasal spray after a single dose in children migraineurs outside of migraine attack. Seventeen subjects (9 females) ages 6 to 11 years were given one dose of sumatriptan nasal spray based on age and weight; children 6 to 8 years of age weighing 25 kg and children ages 9 to 11 years of age weighing 40 kg received 20 mg (n = 4). Plasma sumatriptan concentrations were determined in serial blood samples obtained over 8 hours. Pharmacokinetic analysis included both noncompartmental and population modeling methods. The pharmacokinetic parameter estimates (geometric mean [95% confidence interval]) following 5, 10, and 20 mg sumatriptan were, respectively, as follows: maximum concentration = 8.1 ng/mL (3.6-18.4), 10.8 ng/mL (7.7-15.4), and 12.3 ng/mL (7.6-19.9); half-life = 1.4 hours (1.2-1.8), 1.7 hours (1.4-2.0), and 1.7 hours (1.3-2.3); and AUC = 27.8 ng*h/mL (9.7-79.8), 42.4 ng*h/mL (30.6-58.8), and 49.2 ng*h/mL (32.9-73.7). The median time to maximum concentration for all groups was 2 hours. Population pharmacokinetic modeling included pooled data from this study and from an adolescent study (n = 16). Clearance (CL/F) was 197 L/h for a 30-kg child with between-subject variability of 28%, and the volume of distribution was 751 L, normalized for an 11-year-old child with variability of 43%. The covariate analysis showed that volume increases with age and clearance increases with body size. The absorption was complex, often displaying double-peak plasma concentrations, with a rapid absorption phase and a delayed and rate-limited absorption phase. The dosing scheme based on age and weight resulted in maximal concentrations (C(max)) and systemic exposure (AUC) that were comparable to those observed in adolescents and adults treated with 20 mg. The age- and weight-adjusted dosing scheme appears to an appropriate initial dosing regimen for children with migraine headache. Appropriate safety and efficacy trials will need to be completed in children prior to recommending its use in children.

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.