OBJECTIVE: To evaluate the impact of sumatriptan succinate injection compared with placebo on productivity loss during a migraine attack in the workplace. DESIGN: Randomized, double-blind, placebo-controlled, parallel-group clinical trial. SETTING: Fifteen clinical centers in the United States. PATIENTS: One hundred thirty-five patients 18 years and older diagnosed as having migraine according to International Headache Society criteria. INTERVENTIONS: Patients self-administered sumatriptan injection (6 mg) or matching placebo to treat a moderate or severe migraine occurring within the first 4 hours of a minimum 8-hour work shift. MAIN OUTCOME MEASURES: Mean productivity loss 2 hours after dosing and across the work shift; percentages of patients returning to normal work performance within 2 hours after dosing and across the work shift; percentages of patients experiencing headache relief (reduction of moderate or severe predose pain to mild or no pain) 1 and 2 hours after dosing. RESULTS: Mean productivity loss was significantly (P< or =.002) lower in the sumatriptan group compared with the placebo group both during the 2-hour postdose period (sumatriptan, 39 minutes; placebo, 54 minutes) and across the work shift (sumatriptan, 86 minutes; placebo, 168 minutes). Significantly (P<.001) greater percentages of patients in the sumatriptan group compared with the placebo group returned to normal work performance by 2 hours after dosing (sumatriptan, 52%; placebo, 9%) and across the work shift (sumatriptan, 66%; placebo, 18%). Significantly (P< or =.001) greater percentages of patients in the sumatriptan group compared with the placebo group experienced headache relief 1 hour after dosing (sumatriptan, 69%; placebo, 18%) and 2 hours after dosing (sumatriptan, 79%; placebo, 32%). CONCLUSION: Sumatriptan reduced migraine-associated productivity loss during a minimum 8-hour work shift by approximately 50% compared with placebo and alleviated headache in more than three fourths of patients.