Losartan vs Candesartan
## Overview
Candesartan cilexetil (prodrug → candesartan) and losartan are both ARBs but candesartan has particularly strong evidence in heart failure and is considered one of the most potent ARBs in terms of AT1 receptor affinity.
## Mechanism of Action
Both block AT1. Candesartan has the highest AT1 receptor affinity among ARBs and shows very slow dissociation (insurmountable binding), providing prolonged receptor blockade. Losartan is surmountable.
## Pharmacokinetics
Candesartan cilexetil: prodrug hydrolyzed to candesartan during GI absorption, bioavailability ~42%, half-life ~9 h, biliary/renal elimination, not significantly metabolized by CYP. Losartan: prodrug converted to E-3174 by CYP2C9.
## Clinical Evidence
CHARM program (candesartan) is notable: CHARM-Alternative showed candesartan reduced CV death and HF hospitalizations in ACEi-intolerant HFrEF patients; CHARM-Added showed benefit when added to ACEi. Losartan's landmark HF trial is ELITE II (vs. captopril in elderly HF — non-inferiority, not superiority).
## Key Takeaways
- Candesartan: highest AT1 affinity among ARBs, strong HF evidence (CHARM program)
- Losartan: uricosuric, lower AT1 affinity, surmountable binding
- Candesartan preferred for HFrEF in ACEi-intolerant patients
Veredicto
Candesartan is preferred for heart failure patients intolerant to ACE inhibitors based on CHARM program evidence. Losartan is preferred when uric acid lowering is a secondary therapeutic goal. For hypertension without HF, both are comparable first-line ARBs.