IS OVERUSE OF SUMATRIPTAN A PROBLEM - A POPULATION-BASED STUDY

Objective: Sumatriptan is highly efficacious in aborting acute attacks of migraine. Owing to recent reports of misuse of sumatriptan, we per formed a study of its use in a Danish population. Methods: Data were r etrieved from a prescription database covering a period of 27 months a fter release of the drug. Consumption was described by the defined dai ly dose (DDD) unit and total individual consumption during the period was calculated. Those who received more than one prescription for suma triptan were classified according to peak use of sumatriptan into high (greater than or equal to 60 DDD/31 days) (n = 45), intermediate (30- 59 DDD/31 days) (n = 127) and low (< 30 DDD/31 days) (n = 1423) consum ption groups. Individual usage of other medication was described. Resu lts: We identified 2,878 users of sumatriptan, of whom 1,283 (45%) onl y redeemed one prescription. The use of sumatriptan was highly skewed. The 1% heaviest users accounted for 20% of the total consumption. The median total individual consumption of sumatriptan was 500 DDD, 192 D DD, and 24 DDD in the three groups of multiple redeemers, respectively . Pronounced differences in the total amounts of opioids and ergot alk aloids used were also found, with the high peak consumption group bein g the heaviest consumers of all drug categories, although half of them had only received large doses of sumatriptan. Fifty seven % of high p eak users redeemed more than 29 DDD of sumatriptan within one month of initiation of treatment. The 45 high peak users had received the bulk of their medication, largely in tablet formulation, from 31 prescribe rs. The data points to rebound headache as a plausible underlying mech anism, but incorrect use of sumatriptan for migraine prophylaxis is al so a possibility. Overuse of sumatriptan has serious economic conseque nces and its long-term health effects are not known.