BACKGROUND: In 2009 and 2010 medicines regulatory agencies published official safety statements regarding the concomitant use of proton pump inhibitors and clopidogrel. We wanted to investigate a change in prescription behaviour in prevalent gastrorotective drug users (2008-2011). METHODS: Data on drug use were retrieved from the Out-patient Pharmacy Database of the PHARMO Database Network. We used interrupted time series analyses (ITS) to estimate the impact of each safety statement on the numberof gastroprotective drug switches around the start of clopidogrel and during clopidogrel use. RESULTS: After the first statement (June 2009), significantly fewer patients switched from another proton pump inhibitor to (es)omeprazole (-14.9%; 95% CI -22.6 to -7.3) at the moment they started clopidogrel compared to the period prior to this statement. After the adjusted statement in February 2010, the switch percentage to (es)omeprazole decreased further (-4.5%; 95% CI -8.1 to -0.9). We observed a temporary increase in switches from proton pump inhibitors to histamine 2-receptor antagonists after the first statement; the decrease in the reverse switch was statistically significant (-23.0%; 95% CI -43.1 to -2.9). CONCLUSIONS: With ITS, we were able to demonstrate a decrease in switches from other proton pump inhibitors to (es)omeprazole and an increase of the reverse switch to almost 100%. We observed a partial and temporary switch to histamine 2-receptor antagonists. This effect of safety statements wasshown for gastroprotective drug switches around the start of clopidogrel treatment.