From the FDA Drug Label
5.10 Seizures During premarketing testing in adult patients with schizophrenia, seizures occurred in 0. 3% (9/2607) of RISPERIDONE-treated patients, two in association with hyponatremia. RISPERIDONE should be used cautiously in patients with a history of seizures.
The best antipsychotic to use in the setting of hyponatremia is not specified in the label. Risperidone may be used cautiously in patients with hyponatremia, as seizures have occurred in association with hyponatremia in patients treated with Risperidone. However, the label does not provide a direct comparison with other antipsychotics in the setting of hyponatremia. 1
From the Research
In the setting of hyponatremia, aripiprazole is generally considered the best antipsychotic option due to its lower risk of causing or worsening hyponatremia compared to other antipsychotics. Aripiprazole's favorable profile in this context stems from its unique partial agonist activity at dopamine D2 receptors and lower likelihood of affecting antidiuretic hormone (ADH) secretion, as suggested by various studies 2, 3. The typical starting dose is 5-10 mg daily, which can be titrated up to 15-30 mg daily based on clinical response and tolerability. Other antipsychotics, especially phenothiazines like chlorpromazine, can cause syndrome of inappropriate antidiuretic hormone secretion (SIADH), which worsens hyponatremia.
Some studies have reported cases of hyponatremia associated with the use of olanzapine 4, 5, highlighting the importance of monitoring sodium levels in patients taking antipsychotics. However, aripiprazole is still considered a safer option in terms of hyponatremia risk. When using aripiprazole in patients with hyponatremia, regular monitoring of sodium levels is still essential, particularly during the initial treatment phase. If aripiprazole is not suitable for a specific patient, quetiapine may be considered as an alternative, though with more cautious monitoring of electrolyte levels.
It's worth noting that the incidence of hyponatremia induced by antipsychotics may be higher than currently thought, and both newer atypical antipsychotics and older drugs have been associated with the development of hyponatremia 3. A review of drug-induced hyponatremia also highlights the importance of awareness and proper management of this condition in clinical practice 6.
Key points to consider when using antipsychotics in patients with hyponatremia include:
- Aripiprazole is generally considered the best antipsychotic option due to its lower risk of causing or worsening hyponatremia
- Regular monitoring of sodium levels is essential, particularly during the initial treatment phase
- Other antipsychotics, such as olanzapine, may be associated with a higher risk of hyponatremia
- Quetiapine may be considered as an alternative to aripiprazole, but with more cautious monitoring of electrolyte levels.