Hydroxyzine Dosing in Renal Impairment
In patients with impaired kidney function, the dose of hydroxyzine should be reduced by 50% (halved). 1
Specific Dosing Recommendations
Moderate Renal Impairment (CrCl 10-50 mL/min)
- Reduce the standard dose by 50% 1
- For example, if the typical dose is 25-50 mg at night, reduce to 12.5-25 mg 1
Severe Renal Impairment (CrCl <10 mL/min)
- Avoid hydroxyzine entirely in severe renal impairment 1
- Cetirizine and levocetirizine should also be avoided when creatinine clearance falls below 10 mL/min 1
Rationale for Dose Adjustment
The British Journal of Dermatology guidelines explicitly state that hydroxyzine requires dose reduction in renal impairment because the extent of renal excretion affects drug clearance 1. The FDA drug label confirms that elderly patients with decreased renal function require careful dose selection, typically starting at the low end of the dosing range 2.
The sedating effects of hydroxyzine are particularly problematic in patients with renal impairment, as these patients may experience enhanced CNS depression and confusion 2. This is compounded by the fact that renal disease alters drug pharmacokinetics beyond simple excretion changes, affecting protein binding and drug distribution 3, 4.
Critical Monitoring Parameters
- Start with the lowest effective dose and observe closely for excessive sedation 2
- Monitor for QT prolongation, especially if the patient has electrolyte imbalances (common in kidney disease) 2
- Assess for confusion and over-sedation, which occur more frequently in patients with renal impairment 2
- Avoid concurrent use with other CNS depressants, as the potentiating effects are enhanced in renal disease 2
Important Caveats
Hydroxyzine should be avoided entirely in severe hepatic disease as well, since its sedating effects are inappropriate in this setting 1. The combination of both renal and hepatic impairment creates an even higher risk profile 1.
Patients with kidney disease often have decreased hepatic metabolism in addition to impaired renal clearance, meaning that dose adjustment based solely on creatinine clearance may be insufficient 3, 4. Close clinical monitoring for adverse effects is mandatory regardless of calculated dose adjustments 5.