From the Research
Atypical antipsychotics, particularly aripiprazole, ziprasidone, and lurasidone, are less likely to cause hyponatremia compared to other antipsychotics. When selecting an antipsychotic for patients at risk of hyponatremia (such as elderly patients or those on diuretics), these medications would be preferred options. First-generation antipsychotics like haloperidol and second-generation antipsychotics such as risperidone, olanzapine, and clozapine have been more frequently associated with hyponatremia 1, 2, 3. The mechanism behind antipsychotic-induced hyponatremia typically involves inappropriate antidiuretic hormone secretion (SIADH), which leads to water retention and dilutional hyponatremia. Medications with lower affinity for certain receptors (particularly histamine H1 and alpha-1 adrenergic receptors) may interfere less with water homeostasis.
Some key points to consider when prescribing antipsychotics include:
- Monitoring sodium levels, especially during the first few weeks of treatment and in high-risk patients
- Being aware of the potential for severe hyponatremia with the use of commonly prescribed SGAs 1
- Considering the chemical structures and receptor affinity of the antipsychotics, as well as the influence of concomitant use of other medications known to cause hyponatremia 4
- Differentiating between SIADH and psychogenic polydipsia, which are separate causes of hyponatremia in the psychiatric population 3
Overall, the choice of antipsychotic should be based on the individual patient's risk factors and medical history, with consideration of the potential for hyponatremia and other adverse effects. Aripiprazole, ziprasidone, and lurasidone are generally considered to be lower-risk options for patients at risk of hyponatremia, although careful monitoring and management are still necessary to minimize the risk of this potentially life-threatening complication 5, 1.