Effect of sumatriptan, an antimigraine drug on plasma glucose and insulin

Serotonin, an endogenous biogenic amine plays an important role in blood glucose homeostasis and is known to participate in the etiopathogenesis of migraine as well as diabetes. Drugs which act through serotonin receptors modulate the plasma glucose and insulin level in animals and healthy humans. Therefore, the present study was undertaken to study the effect of sumatriptan a 5-HT_1A receptor agonist used as an anti-migraine drug, on plasma glucose and insulin levels in healthy human volunteers. Each volunteer received either sumatriptan or placebo in a randomized cross over the study with a one-week wash out period in between. Volunteers were given oral glucose challenge at the time when the drug attained maximal plasma concentration. The blood samples were collected before dosing, after dosing and after glucose challenge test at 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 h following sumatriptan or placebo administration. Plasma glucose and insulin levels were determined by using kits based on the principle of glucose hexokinase and ELISA respectively. Sumatriptan produced a significant decrease in plasma glucose levels without significant effect on insulin level in comparison with placebo. The result of the present study suggest that sumatriptan may alter the glucose homeostasis and poses a risk in glucose intolerant or individuals who prone to develop diabetes mellitus or diabetic patients.