1418Adverse effects of spironolactone in long-term treatment of resistant arterial hypertension

Background Spironolactone is recommended as a fourth line antihypertensive drug by current hypertension guidelines. This drug had relatively few adverse effects in short term clinical trials, but data about their occurrence during long-term treatment of resistant hypertension are scarce. Purpose To evaluate the occurrence and type of adverse effects of spironolactone during long-term treatment and their possible clinical and laboratory predictors. Methods We prospectively followed 274 patients with resistant arterial hypertension who started treatment with spironolactone between September 2007 and December 2016. The duration of spironolactone use, its dose, the incidence of adverse events, blood pressure, and laboratory findings were recorded at baseline and during the last clinical examination. Results Patients were followed for an average of 35 (± 29) months, the mean dose of spironolactone was 27.5 mg/day. Adverse effects occurred in 72 patients (26.3%) and in 61 (84.7%) lead to discontinuation of spironolactone. The most common adverse reactions were gynaecomastia (30.6%), hyperkalaemia (30.6%) and symptomatic hypotension (26.4%). The mean duration of spironolactone treatment before their occurrence was 25 (± 27) months. According to the Kaplan-Meier curve, the median for the incidence of adverse events would be 97 months (91.5–102.5 months), i.e. 50% of patients could be treated with no adverse events for more than 8 years. Adverse events were more common in the elderly (hazard ratio – HR 1.38, P=0.007), patients with higher baseline serum creatinine (HR 1.12, P=0.035) and patients taking angiotensin receptor blockers (HR 1.65, P=0.040). Kaplan-Meier estimate – adverse events Conclusion During long-term treatment of resistant hypertension with spironolactone, more than a quarter of patients experience adverse reactions that usually require discontinuation of spironolactone. Acknowledgement/Funding Supported by the grants of Palacký University in Olomouc Nr. IGA_LF_2016_038 and IGA_LF_2017_029.