Is Hydralazine Dialyzable?
No, hydralazine is not effectively removed by dialysis due to its high protein binding (87%) and extensive hepatic metabolism, making dose adjustments for dialysis unnecessary.
Pharmacokinetic Properties Preventing Dialyzability
The FDA drug label clearly states that hydralazine has 87% binding to human plasma protein 1. This high degree of protein binding is the primary reason hydralazine cannot be effectively removed by hemodialysis, as dialysis membranes cannot efficiently clear protein-bound drugs.
Additionally, hydralazine undergoes extensive hepatic metabolism and is excreted mainly in the form of metabolites in the urine rather than as unchanged drug 1. This metabolic pathway further reduces the likelihood of significant drug removal during dialysis sessions.
Clinical Implications in Dialysis Patients
No dose adjustment is required for patients on maintenance dialysis, as the drug is not significantly removed during dialysis sessions 1
Hydralazine can be safely used in patients with end-stage kidney disease on dialysis, with recent data showing potential cardiovascular benefits in this population 2
The drug's half-life of 3 to 7 hours and its metabolism are not significantly altered by renal impairment, as elimination depends primarily on hepatic pathways rather than renal excretion 1, 3
Practical Considerations
Timing of administration does not need to be coordinated with dialysis sessions, as the drug will not be removed during treatment 1
The combination of hydralazine-isosorbide dinitrate has shown efficacy in dialysis patients with heart failure, with lower all-cause mortality rates compared to non-users 2
Monitor for the drug's expected effects (reflex tachycardia, blood pressure reduction) regardless of dialysis timing, as pharmacodynamic responses remain intact 1