From the FDA Drug Label
Mirtazapine clearance is decreased in patients with moderate [glomerular filtration rate (GFR) = 11 to 39 mL/min/1.73 m 2] and severe [GFR < 10 mL/min/1. 73 m 2] renal impairment, and also in patients with hepatic impairment. Caution is indicated in administering mirtazapine to such patients (see CLINICAL PHARMACOLOGYand DOSAGE AND ADMINISTRATION)
- Key Points: + Mirtazapine clearance is decreased in patients with moderate and severe renal impairment. + Caution is indicated when administering mirtazapine to patients with impaired renal function.
- Mirtazapine is not contraindicated in patients with impaired renal function, but caution is advised due to decreased clearance 1.
From the Research
Mirtazapine is not contraindicated in patients with renal impairment and can be safely used in patients with kidney disease, including those with reduced renal function or on dialysis, without dose adjustment. This is because mirtazapine is primarily metabolized by the liver through the cytochrome P450 enzyme system, with minimal renal excretion of the parent compound or its metabolites. Only about 15% of the drug is eliminated through the kidneys, making it a suitable antidepressant option for renal patients 2.
Key Considerations
- Mirtazapine's pharmacokinetics make it a favorable choice for patients with renal impairment, as it does not require dose adjustments based on renal function alone 2.
- However, while formal dose adjustments aren't required, clinicians should still monitor these patients closely for side effects, as there may be a theoretical risk of increased drug exposure due to altered protein binding or other pharmacokinetic changes in severe renal disease.
- Common side effects to watch for include sedation, increased appetite, weight gain, and dry mouth.
- Starting at a lower dose (such as 7.5 mg or 15 mg at bedtime) and titrating slowly may be prudent in patients with severe renal impairment.
Monitoring and Dose Adjustment
- Although dose adjustments are not typically necessary, monitoring for side effects and adjusting the dose based on clinical response and tolerability is recommended.
- The use of mirtazapine in patients with renal impairment should be guided by the principles of minimizing risk and maximizing benefit, with careful consideration of the patient's overall clinical condition and other medications that may interact with mirtazapine 3, 2.
Conclusion Not Applicable - Direct Answer Only
The most recent and highest quality evidence supports the use of mirtazapine in patients with renal impairment without dose adjustment, emphasizing the importance of careful monitoring and clinical judgment in managing these patients 2.