Can Quetiapine (Seroquel) cause hyponatremia?

Quetiapine and Hyponatremia

Yes, quetiapine can cause hyponatremia through syndrome of inappropriate antidiuretic hormone secretion (SIADH). This is documented in the FDA drug label and supported by multiple case reports.

Evidence for Quetiapine-Induced Hyponatremia

• The FDA drug label for quetiapine explicitly lists hyponatremia as a post-marketing adverse reaction that has been temporally related to quetiapine therapy 1
• Quetiapine has been associated with syndrome of inappropriate antidiuretic hormone secretion (SIADH), which is the primary mechanism for drug-induced hyponatremia 1
• Case reports document extreme hyponatremia (serum sodium as low as 97 mmol/L) in patients taking quetiapine 2
• Multiple published cases confirm quetiapine-induced SIADH as a rare but serious adverse effect 3, 4, 5

Risk Factors and Mechanisms

• Patients with schizophrenia are particularly susceptible to hyponatremia due to the association between this condition and primary polydipsia 2
• The combination of primary polydipsia and quetiapine-induced SIADH can lead to life-threatening, extreme hyponatremia 2
• The antidiuretic effect of vasopressin limits the kidney's ability to excrete free water in response to excessive water intake, resulting in dilutional hyponatremia 2
• Risk factors for developing SIADH include:
  • Increasing age 5
  • Comorbid somatic disorders 5
  • Polypharmacy 5

Clinical Presentation and Monitoring

• Symptoms of quetiapine-induced hyponatremia may include:

  • Confusion 2, 4
  • Vomiting 2
  • Seizures 3
  • Altered mental status 2, 4
  • Urinary complaints and increased urgency 4
  • Thirst 4

• Monitoring recommendations:

  • Monitor serum sodium during the first 2-4 weeks of quetiapine therapy, especially in high-risk patients 5
  • Be particularly vigilant when initiating or adjusting quetiapine dosage in patients with known primary polydipsia 2

Management of Quetiapine-Induced Hyponatremia

• For symptomatic hyponatremia (a medical emergency):

  • Treatment with boluses of hypertonic 3% saline may be required 2
  • Correction should not exceed 8 mmol/L over 24 hours, especially when sodium is below 105 mmol/L, due to risk of osmotic demyelination syndrome 2

• For less severe cases:

  • Implement a restrictive fluid policy 4
  • Consider reduction or discontinuation of quetiapine 4, 5
  • Consider switching to an alternative antipsychotic with lower risk of SIADH 5

Comparative Risk Among Antipsychotics

• Both newer atypical antipsychotics (like quetiapine) and older typical antipsychotics have been associated with hyponatremia 6
• In one case report, a patient who developed SIADH with both haloperidol and quetiapine did not experience this side effect when switched to clozapine 5

Clinical Implications

• The incidence of antipsychotic-induced hyponatremia may be higher than currently recognized 6
• Healthcare providers should maintain a high index of suspicion for hyponatremia in patients taking quetiapine, especially those with risk factors 5, 6
• Early recognition is vital for timely initiation of correct treatment to prevent permanent neurological consequences 4