citalopram and ibuprofen

Citalopram, as a selective serotonin reuptake inhibitor (SSRI), reduces platelet serotonin levels, which impairs platelet aggregation and increases bleeding tendency. Ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), inhibits cyclo-oxygenase enzymes, decreasing production of thromboxane A2 and prostaglandins, which further impairs platelet function and also causes gastrointestinal mucosal damage. The pharmacodynamic effects are additive, resulting in a significantly increased risk of gastrointestinal bleeding when the two drugs are used together.

The combination of citalopram and ibuprofen is associated with an increased risk of upper gastrointestinal bleeding, particularly in elderly patients, those with a history of peptic ulcer disease, or those taking other medications that affect coagulation. The bleeding risk is higher than with either drug alone and can lead to serious complications such as anaemia, haemorrhagic shock, or death, although such outcomes are uncommon in otherwise healthy individuals.

When citalopram and ibuprofen are co-prescribed, use caution and consider alternative analgesia such as paracetamol if appropriate. If an NSAID is necessary, use the lowest effective dose for the shortest duration, and administer a gastroprotective agent such as a proton pump inhibitor, especially in patients with risk factors. Monitor patients for signs of gastrointestinal bleeding, including black stools, melaena, haematemesis, or unexplained anaemia, and advise them to seek prompt medical attention if these occur.

This interaction is well established in the literature and is supported by pharmacoepidemiological studies and case reports. Both SSRIs and NSAIDs independently increase the risk of gastrointestinal bleeding, and the combination has an additive effect. The interaction is recognised by major drug interaction databases and regulatory bodies, and guidelines recommend caution when prescribing these drugs together.