Can Buspar (Buspirone) Cause Hyponatremia?
Buspirone is not a recognized cause of hyponatremia and does not appear in clinical guidelines or major reviews of hyponatremia-inducing medications.
Evidence Assessment
The available evidence does not support buspirone as a causative agent for hyponatremia:
Major drug classes associated with hyponatremia include psychotropic agents (antipsychotics, antidepressants, anticonvulsants), anticancer chemotherapeutic agents, and thiazide diuretics 1, 2.
Specific psychotropic medications implicated in hyponatremia include haloperidol, sertraline, carbamazepine, and bupropion (not buspirone), which can upregulate vasopressin V2 receptors and aquaporin-2 channels, leading to nephrogenic syndrome of inappropriate antidiuresis (NSIAD) 1, 3.
Buspirone's pharmacological profile differs fundamentally from hyponatremia-inducing agents. It acts primarily on serotonin 5-HT1A receptors and dopamine D2 autoreceptors, with rapid elimination (half-life ~2.5 hours) and no accumulation with repeated dosing 4, 5.
Common adverse effects of buspirone include headaches, dizziness, nervousness, and lightheadedness—but hyponatremia is not listed among recognized side effects 5.
Clinical Context
When evaluating hyponatremia in a patient taking buspirone:
Look for alternative causes including thiazide diuretics (which cause hyponatremia in up to 30% of patients through intrarenal AQP2 upregulation), SSRIs, antipsychotics, anticonvulsants, or other medications 6, 1.
Consider underlying conditions such as cirrhosis (where hyponatremia occurs in ~49% of patients with ascites), heart failure, or SIADH from other etiologies 6.
Assess volume status to determine if hyponatremia is hypovolemic (from diuretics or GI losses), euvolemic (SIADH), or hypervolemic (cirrhosis, heart failure) 7.
Common Pitfall to Avoid
Do not attribute hyponatremia to buspirone without thoroughly investigating other medications and underlying conditions. The absence of buspirone in comprehensive reviews of drug-induced hyponatremia 1, 2 and in major clinical guidelines for hyponatremia management 6, 7 strongly suggests it is not a causative agent. If hyponatremia develops in a patient on buspirone, conduct a systematic evaluation for alternative causes rather than discontinuing buspirone prematurely.