Canadian researchers monitored hospital admissions for gastrointestinal bleeding among almost 314,000 people, aged 65 and above, who had been prescribed antidepressants between 1992 and 1998. Antidepressant drugs were grouped according to what extent they inhibited serotonin re-uptake.
There were 974 gastrointestinal bleeds during the study. The higher the inhibition of serotonin re-uptake, the higher was the risk of a bleed. This was especially true of older patients in whom the risk increased by over 10 per cent for each more powerful grade of inhibitor drug, and those who had already had a bleed, in whom the risk increased by almost 10 per cent.
For patients in their 80s, bleeding rates increased from 10.6 per 1000 person years for drugs with the lowest inhibition to 14.7 with the highest. This equals an additional bleed for every 244 patients treated with the highest inhibiting drugs for a year. The data also showed that the numbers of 80 year olds prescribed SSRIs rose from 892 in 1192 to 11,179 in 1997.
Among patients who had had peptic ulcers, bleeding rates increased from over 28 to over 40 per 1000 person years. This equates to an additional bleed for every 85 patients treated with the highest inhibiting drugs for a year.
The authors conclude that the extent to which antidepressants inhibit serotonin re-uptake should be considered before prescribing these drugs to very elderly patients or those who have had a bleed before.