OBJECTIVE: To investigate whether the intensity of triptan and ergotamine use, in specific overuse, is associated with the risk of ischemic complications. METHODS: We conducted a retrospective nested case-control study using data from the PHARMO Reord Linkage System. All patients with more than one prescription for either a triptan or ergotamine were initially identified. Cases were all patients who were admitted to the hospital for an ischemic complication. Matched controls were assigned the sameindex date as the cases. The determinant was the intensity of use of triptans and ergotamine during 1 year preceding the index date. Overuse was defined as use of > or =90 defined daily doses during that year. Conditional logistic regression was used toestimate odds ratios (ORs), adjusting for confounders. Stratified analysis was used to estimate the risk for both patients using and those not using cardiovascular drugs. RESULTS: A total of 17,439 patients received more than one prescription. A total of 188 cases and 689 controls were identified. Triptan overuse was not associated with an increased risk of ischemic complications (OR 0.96; 95% CI: 0.49 to 1.90). Overuse of triptans in patients concomitantly using cardiovascular drugs did not increase this risk. Overuse of ergotamine turned out to be a risk factor for ischemic complications (OR 2.55; 95% CI: 1.22 to 5.36). Patients overusing ergotamine and concomitantly using cardiovascular drugs were at highest risk (OR 8.52; 95% CI 2.57 to 28.2). CONCLUSIONS: In general practice, triptan overuse does not increase the risk of ischemic complications. Overuse of ergotamine may increase the risk of these complications, especially in those simultaneously using cardiovascular drugs.