What medications can cause ketonuria?

Medications That Can Cause Ketonuria

Antipsychotic medications, particularly olanzapine and clozapine, are the most significant medications that can cause ketonuria due to their association with diabetic ketoacidosis, even in patients without pre-existing diabetes. 1, 2

Common Medications Associated with Ketonuria

1. Antipsychotic Medications

• Second-generation antipsychotics (SGAs)

  • Olanzapine: FDA label specifically warns about hyperglycemia that can be "extreme and associated with ketoacidosis" 1
  • Clozapine: High risk for metabolic disturbances leading to ketoacidosis 2
  • Risperidone: Associated with glucose metabolism disturbances 2
  • Quetiapine: Can cause hyperglycemia and ketosis 2, 3

• Risk factors for antipsychotic-induced ketoacidosis:

  • First 6 months of treatment (highest risk period)
  • Pre-existing insulin resistance
  • Male gender
  • Middle age
  • Polypharmacy 2

2. SGLT2 Inhibitors

• Mechanism: Induce glycosuria and increase ketone production
• Examples:
  • Dapagliflozin
  • Empagliflozin
  • Sotagliflozin
• Note: While SGLT2 inhibitors can cause diabetic ketoacidosis, ketonuria may actually be associated with improved renal function in some patients 4

3. Diuretics

• Loop diuretics:
  • Furosemide
  • Bumetanide
  • Torsemide
• Thiazide diuretics:
  • Chlorthalidone
  • Hydrochlorothiazide
  • Indapamide
• Mechanism: Volume depletion and metabolic disturbances can trigger ketogenesis 5

4. Mineralocorticoid Receptor Antagonists

• Examples:
  • Spironolactone
  • Eplerenone
• Mechanism: Can cause metabolic acidosis and electrolyte disturbances that may contribute to ketone formation 5

Clinical Implications and Monitoring

1. For antipsychotic medications:

   • Screen for diabetes before and during treatment
   • Monitor fasting blood glucose regularly, especially during first 6 months
   • Consider ketone testing in patients with symptoms of hyperglycemia
   • Be vigilant for signs of diabetic ketoacidosis (nausea, vomiting, abdominal pain)

2. For SGLT2 inhibitors:

   • Monitor for ketones during illness or stress
   • Be aware that euglycemic DKA can occur (ketoacidosis without marked hyperglycemia)
   • Some ketonuria may be expected and potentially beneficial 4

3. For diuretics and other medications:

   • Monitor electrolytes and renal function
   • Be cautious with combination therapy that may increase risk
   • Consider ketone testing in patients with unexplained metabolic acidosis

Diagnostic Considerations

• Blood ketone testing is preferred over urine testing for diagnosing and monitoring DKA 5
• Beta-hydroxybutyrate is the predominant ketone in blood during DKA 6
• Urine ketone tests using nitroprusside only detect acetoacetate and acetone, not beta-hydroxybutyrate 5
• False positive urine ketone results can occur with certain medications (e.g., captopril) 5

Prevention Strategies

1. Regular monitoring of glucose levels in patients on high-risk medications
2. Avoid polypharmacy when possible, especially combinations of metabolically active drugs
3. Patient education about symptoms of hyperglycemia and ketoacidosis
4. Consider alternative medications in patients with multiple risk factors

Remember that while ketonuria can be medication-induced, it may also indicate other serious conditions such as starvation, alcoholic ketoacidosis, or diabetic ketoacidosis that require prompt medical attention.