Antipsychotics and severe hyponatremia: A Swedish population–based case–control study

Antipsychotics have been claimed to cause hyponatremia. The risk associated with individual antipsychotics, or groups (first-generation [FGAs] or second-generation [SGAs] antipsychotics), is not well-documented. The objective of this study was to investigate the association between antipsychotics and hospitalization due to hyponatremia. The general Swedish population was the base of this register–based case–control study. Comparisons were made between patients hospitalized with a principal diagnosis of hyponatremia (n = 14,359) and matched controls (n = 57,383). Multivariable logistic regression adjusting for concomitant drugs, medical conditions, previous hospitalizations and socioeconomic factors was performed to investigate the association between hyponatremia and antipsychotic use. In addition newly initiated (≤90 days) or ongoing use was analysed separately. Compared to controls, the adjusted OR (95%CI) for hospitalization due to hyponatremia was for any antipsychotic 1.67(1.5–1.86). Individuals on FGA were more likely to experience severe hyponatremia (2.12[1.83–2.46]) than those on any SGA (1.32[1.15–1.51]). No increased risks, neither as newly initiated nor ongoing therapy, were found for risperidone (0.86[0.56–1.31] and 0.83[0.67–1.02]) and aripiprazole (1.16[0.30–4.46] and 0.62[0.27–1.34]), respectively. There was an association between antipsychotic therapy and hospitalization due to hyponatremia. The association was stronger for FGAs than SGAs. Risperidone was not associated with an increased risk. •There was an association between antipsychotics, and hospitalization due to hyponatremia•The association was stronger for first-generation than second-generation antipsychotics•Risperidone was not associated with an increased risk•In severe hyponatremia with antipsychotics, consider an alternative•If the indication for antipsychotic use remains, risperidone could here be an option