Can I prescribe atomoxetine (Strattera) to a patient with impaired renal function on dialysis?

Atomoxetine in Patients on Dialysis

Atomoxetine can be safely prescribed to patients with end-stage renal disease on dialysis without dose adjustment, as it does not require dosage modification in renal insufficiency according to the FDA label. 1

Pharmacokinetics in Renal Impairment

• The FDA label explicitly states that patients with end-stage renal disease (ESRD) had only about a 65% increase in systemic exposure to atomoxetine compared to healthy subjects, but there was no difference when exposure was corrected for mg/kg dose 1
• Unlike many other medications that require significant dose adjustments in renal failure, atomoxetine can be administered to ADHD patients with ESRD or lesser degrees of renal insufficiency using the normal dosing regimen 1
• This is supported by research showing that while renal impairment can reduce hepatic CYP2D6 activity and atomoxetine elimination, the clinical significance of the exposure increase does not warrant dose adjustment 2

Clinical Decision-Making Algorithm

1. Confirm indication: Ensure atomoxetine is being used for an appropriate indication (typically ADHD)
2. Review patient's medication list: Check for potential drug interactions, particularly:
   • MAO inhibitors (contraindicated with atomoxetine) 1
   • CYP2D6 inhibitors (may increase atomoxetine plasma concentrations) 1
   • Antihypertensive medications (possible effects on blood pressure) 1
   • Albuterol or other beta2 agonists (cardiovascular effects may be potentiated) 1
3. Start with standard dosing: No dose adjustment is required specifically for renal impairment 1
4. Monitor for side effects: Pay particular attention to:
   • Cardiovascular effects (blood pressure, heart rate)
   • Hepatic function (atomoxetine carries a warning for severe liver injury)
   • Psychiatric symptoms (mood changes, aggression, suicidal ideation)

Important Considerations

• While many medications require dose adjustments in patients with renal impairment, atomoxetine is primarily metabolized by the liver through the CYP2D6 pathway, with renal excretion playing a minor role in elimination 1, 2
• Be aware that patients with renal failure often have multiple comorbidities and take numerous medications, increasing the risk of drug interactions 3
• Atomoxetine carries warnings for serious cardiovascular events, increased blood pressure and heart rate, which may be particularly relevant in dialysis patients who often have cardiovascular comorbidities 1

Common Pitfalls to Avoid

1. Assuming dose reduction is needed: Unlike many psychotropic medications, atomoxetine does not require dose adjustment in renal failure 1
2. Overlooking cardiovascular monitoring: Patients on dialysis often have cardiovascular disease, so monitor blood pressure and heart rate carefully when using atomoxetine 1
3. Missing drug interactions: Patients on dialysis typically take multiple medications; carefully review for potential interactions 3, 4
4. Neglecting hepatic function: While renal function doesn't require dose adjustment, hepatic impairment does require dose modification (moderate hepatic impairment: 50% of normal dose; severe hepatic impairment: 25% of normal dose) 1

By following these guidelines, atomoxetine can be safely prescribed to patients on dialysis without the need for specific dose adjustments related to their renal status, though careful monitoring for side effects and potential drug interactions remains important.