LAUSR

To the Editors: H yponatremia/syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is a disorder of impaired water excretion caused by the inability to suppress the secretion of antidiuretic hormone (ADH). If water intake exceeds the reduced urine output, the resultant water retention leads to the development of hyponatremia. Hyponatremia/SIADH is known with the use of nearly all antipsychotics andmood stabilizers. Drug-associated SIADH is more likely to have atypical initial symptoms and may not always be reported by the patient resulting in clinical worsening. Symptoms of hyponatremia/SIADH are usually nonspecific; however, serious sequelae, such as confusion, coma, respiratory arrest, and even death, may also occur. Delayed diagnosis and management may have more serious or even life-threatening consequences. Paliperidone is an atypical antipsychotic drug with high affinity for the serotonin 5-HT2A and dopamine 2 (D2) receptors. 4