OBJECTIVES: To build an economic model estimating the costs of care for chest pain in migraine patients when treated with almotriptan instead of sumatriptan. METHODS: We conducted a population-based retrospective cohort study from the MEDSTAT Marketscan database. Patients were continuously enrolled for any two consecutive years between 1996 and 1998 and had a first prescription for oral sumatriptan between July 1, 1996 and June 30, 1998. Exclusion criteria included contraindications or risk factors for coronary artery disease. The baseline and treatment periods were defined as five months before and after the date of the first prescription minus 15 days (since most patients receive samples). Patients with chest pain-related diagnoses and procedures were compared between periods using the McNemar test. The cost of chest pain-related care was used to build a model estimating costs based on rates of chest pain from clinical trials. RESULTS: Of 1,759 patients meeting inclusion criteria, 369 were excluded. The final cohort of 1,390 migraine patients showed a statistically significant increase in the number experiencing chest pain after treatment with sumatriptan (compared to the baseline period) from 110 to 158 (p=0.003), a 43.6% increase. Associated costs increased from $22,713 to $30,234. The model estimated annual cost savings of $11,215 per 1,000 patients for migraine treated with almotriptan instead of sumatriptan due to lower rates of chest pain (0.3% vs. 2.2%, p=0.004). CONCLUSIONS: Direct medical cost savings are predicted for health plans from migraine patients switched from sumatriptan to almotriptan based on the lower rate of chest pain.