Is Olmesartan Dialyzable?
No, olmesartan is not effectively removed by hemodialysis due to its high protein binding (99%), making it non-dialyzable in patients with impaired renal function. 1, 2
Pharmacokinetic Properties That Prevent Dialyzability
- Olmesartan exhibits 99% plasma protein binding, which prevents significant removal during hemodialysis since only unbound drug can be cleared by dialysis 1
- The volume of distribution is approximately 17 L, and olmesartan does not penetrate red blood cells, further limiting dialytic clearance 1
- Direct clinical evidence demonstrates that plasma concentrations of olmesartan do not decrease during hemodialysis sessions, with area under the curve (AUC) values remaining similar whether the drug is taken on dialysis days or non-dialysis days 2
Clinical Evidence in Hemodialysis Patients
- A pharmacokinetic study in six maintained hemodialysis patients showed no remarkable difference in AUC between hemodialysis days and non-hemodialysis days 2
- Comparison of plasma concentrations upstream versus downstream of the dialyzer at three time points showed no significant removal of olmesartan during dialysis 2
- No dosing adjustment is necessary on hemodialysis days, as the drug's pharmacokinetic parameters (Cmax, t1/2, tmax) remain unchanged regardless of dialysis timing 2
Renal Impairment Considerations
- In patients with severe renal impairment (creatinine clearance <20 mL/min), serum concentrations of olmesartan are approximately tripled after repeated dosing compared to those with normal renal function 1
- The FDA label recommends a maximum daily dose of 20 mg (rather than the standard 40 mg) in patients with severe renal insufficiency 1, 3
- Approximately 35-50% of absorbed olmesartan is recovered in urine, with the remainder eliminated via bile into feces, but this renal clearance (0.6 L/h) represents only a fraction of total plasma clearance (1.3 L/h) 1
Important Clinical Pitfalls
- The pharmacokinetics of olmesartan in patients undergoing hemodialysis has not been formally studied by the FDA, though independent research fills this gap 1, 2
- Unlike some beta-blockers (such as atenolol and sotalol) that are dialyzable in patients with kidney impairment, angiotensin receptor blockers like olmesartan behave differently due to their high protein binding 4
- Olmesartan can cause acute renal failure in patients with bilateral renal artery stenosis, even after a single dose, requiring caution and close monitoring of renal function in at-risk patients 5
Practical Prescribing Algorithm
- For hemodialysis patients: Administer olmesartan at any time relative to dialysis sessions, as timing does not affect drug levels or blood pressure control 2
- For severe renal impairment (CrCl <20 mL/min): Limit dose to maximum 20 mg daily due to tripled drug exposure 1, 3
- For moderate hepatic impairment: Also limit to 20 mg daily, as AUC increases by approximately 60% 1
- Monitor blood pressure and renal function closely, particularly in the first weeks of therapy, as olmesartan provides preferential nighttime blood pressure reduction and antiproteinuric effects in CKD patients 6, 7