We observed an increased rate ratio for severe hypotension requiring admission to hospital with [Flomax (tamsulosin)] treatment. The greatest increase in risk — varying in magnitude from 151% to 256% — was observed during the first eight weeks of new drug use and the first eight weeks after restarting drug treatment. A smaller increase in risk for hypotension, varying from 19% to 36%, persisted during maintenance [Flomax (tamsulosin)] treatment.