Kounis syndrome: A retrospective analysis of individual case safety reports from the international WHO database in pharmacovigilance

Objective: Kounis syndrome (KS) is an acute coronary syndrome with coronary spasm, acute myocardial infarction and stent thrombosis that can be associated with a variety of drugs as an adverse drug reaction (ADR). To characterize this rare phenomenon, we analyzed all cases of KS in the WHO database for pharmacovigilance. Materials and methods: All cases of KS worldwide until December 31, 2017, were included and analyzed in terms of age, sex, country, year of ADR, seriousness, clinical outcome, suspected drugs, administration, reported reaction, and - MedDRA terms. Time to onset of the ADR was calculated, and a subgroup analysis of KS associated with analgesics was performed. IC025 values were calculated for the most frequently reported pain medication to indicate the strength of relation between ADR and the suspected analgesics. Results: A total of 403 cases of KS reported from 17 countries were included, of which 121 cases were associated with analgesics (subgroup). Males were more frequently affected overall (267 (66%) males vs. 123 (31%) females), whereas in the subgroup, males and females were equally affected (58 (48%) males vs. 56 (46%) females). Median reported patient age was 57 years (range 2 - 99) overall vs. 48 years (range 20 - 85) in the subgroup. Nearly all cases were classified as serious (370 (92%) overall vs. 119 (98%) subgroup). The most frequently suspected substance was amoxicillin/clavulanic acid (n = 50, 9.3%) overall and ibuprofen (n = 33, 6.2%) in the subgroup, respectively. Most drugs were administered orally (21% overall vs. 21% subgroup) and intravenously (18.7% overall vs. 8% subgroup) in either group. A high proportion of patients with "life threatening" reactions received intravenous administration (37%) of the suspected drug. Conclusion: Antibiotics and analgesics are the drug classes most often associated with KS. The way of administration might have an influence on the seriousness of the reaction.