Candesartan: the pathway in the body
This page shows the biochemical pathway of the active substance Candesartan: where it arrives in the body, where it acts and which steps are affected by that. Every statement has a source. The page describes general textbook knowledge and says nothing about any individual person.
In brief
Candesartan is an AT1 receptor antagonist, given as an ester precursor. It occupies the pocket of the receptor into which angiotensin II otherwise reaches, and comes away only slowly — the messenger still arises but finds the pocket taken.
What this is about
Angiotensin II is the most potent vessel-narrowing messenger of the renin-angiotensin system. It does not act by itself but through a receptor in the cell membrane — the AT1 receptor. Two places matter here:
- The smooth muscle of the vessel wall. There the occupied receptor frees the messenger IP3 via Gq and phospholipase C; calcium rises inside the cell, and the muscle cell shortens.
- The adrenal cortex. There the same path leads the outer cell layer to form the hormone aldosterone and release it into the blood.
- Aldosterone regulates in the kidney how much sodium is reclaimed and how much potassium is released.
- Candesartan cilexetil is the ester precursor. The ester group is cleaved off already during the passage out of the bowel; what reaches the blood is the active form.
Candesartan lays itself into the same pocket of the AT1 receptor into which angiotensin II otherwise reaches, and comes away from it only slowly. It thus acts at the other end of the same axis than an ACE inhibitor does: angiotensin II still arises — the label even describes a rise of renin and angiotensin II — it merely no longer finds its receptor free. The enzyme ACE itself remains untouched; bradykinin is therefore still taken apart as before.
What this means in an individual case depends on many things and belongs in a conversation with a doctor or health practitioner.
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The pathway step by step
- Candesartan cilexetil → Uptake in the gut wall Already during the passage out of the bowel, esterases cleave off the ester group. The label describes the precursor as being fully converted to the active form in the process; it reaches the blood already converted. Source 6, 9
- Uptake in the gut wall → Candesartan esterases of the gut Candesartan is the form that acts at the receptor. It carries an acid group and a tetrazole ring; both reach into the binding pocket of the AT1 receptor and come away from it only slowly. Source 3, 6
- Candesartan → Travelling in the blood In the blood candesartan hangs almost entirely on proteins. It is hardly remodelled; the label names kidney and bile as the routes by which it leaves the body again. Source 6, 9
- Smooth muscle cell → Calcium in the cell Gq, phospholipase C The switched-on receptor sets the G protein Gq going. Phospholipase C then splits a fat of the cell membrane and frees IP3; IP3 opens the calcium stores, and calcium rises inside the cell. Source 2, 8
- Calcium in the cell → Muscle cell contracts The rise of calcium sets the contractile apparatus of the muscle cell going. The cell shortens, and the diameter of the vessel becomes smaller. Source 8, 1
- Angiotensinogen → Angiotensin I Renin Renin from the kidney cuts a piece of ten amino acids off angiotensinogen: angiotensin I. This chain does not yet bind to either receptor. Source 1
- Angiotensin I → Angiotensin II ACE · zinc in the centre, chloride ACE cleaves the last two amino acids off angiotensin I. What remains is angiotensin II. It binds at the AT1 receptor and makes the smooth muscle of the vessels narrower. Source 1, 2, 9
- Angiotensin II → Aldosterone AT1 receptor Angiotensin II also binds at the AT1 receptor of the adrenal cortex. The cortex then releases the hormone aldosterone into the blood. Source 1, 4, 9
- Aldosterone → Sodium and potassium ENaC, Na-K pump Aldosterone makes the kidney reclaim more sodium in the collecting duct and release more potassium. With the receptor occupied both shift; the label describes only a small change of serum potassium. Source 5, 9
What the AT1 receptor governs
- Sodium — Aldosterone governs how much sodium the kidney reclaims in the collecting duct Source 1, 5
- Potassium — Aldosterone governs the release of potassium in the collecting duct of the kidney; less aldosterone shifts it Source 5, 9
- Calcium — Rises in the vascular muscle cell when the AT1 receptor opens the calcium stores via IP3 Source 2, 8
What takes part in these steps
- Inositol — Building block of PIP2, from which phospholipase C splits off IP3 after the receptor signal Source 8
- Magnesium — Forms with ATP the complex that the sodium-potassium pump in the collecting duct turns over Source 7
- ATP — Energy source of the sodium-potassium pump through which aldosterone moves sodium and potassium Source 7
What the prescribing information states
Placebo-controlled trials with 2,350 adults on candesartan and 1,027 on placebo. The prescribing information lists here the reactions that occurred in at least 1 of 100 participants and were more frequent on candesartan than on placebo. There is no column for an active comparator — at this place the prescribing information carries no third group.
How to read the table: what matters is the comparison within the row, not the single figure. Three points belong with it — for the first five rows the prescribing information selected only those reactions that were more frequent on candesartan than on placebo; anything that occurred equally often, or more often on placebo, does not appear there at all. The last row comes from the same section and ran the other way. And a third column with an active comparator is missing because the prescribing information carries none at this place.
| Candesartan (2,350) | Placebo (1,027) | |
|---|---|---|
| Upper respiratory tract infection | 6% | 4% |
| Dizziness | 4% | 3% |
| Back pain | 3% | 2% |
| Pharyngitis | 2% | 1% |
| Rhinitis | 2% | 1% |
| Stopped because of adverse events | 2.4% | 3.4% |
Further reactions have been reported after approval. The prescribing information notes that neither a frequency nor a causal relationship can be derived from such reports; they are therefore not listed here.
Sources
- Triebel H, Castrop H. The renin angiotensin aldosterone system. Pflugers Arch 2024 · PubMed 38233636
- Eckenstaler R, Sandori J, Gekle M et al. Angiotensin II receptor type 1 - An update on structure, expression and pathology. Biochem Pharmacol 2021 · PubMed 34252409
- Van Liefde I, Vauquelin G. Sartan-AT1 receptor interactions: in vitro evidence for insurmountable antagonism and inverse agonism. Mol Cell Endocrinol 2009 · PubMed 18620019
- Bollag WB. Regulation of aldosterone synthesis and secretion. Compr Physiol 2014 · PubMed 24944029
- Palmer BF. Regulation of Potassium Homeostasis. Clin J Am Soc Nephrol 2015 · PubMed 24721891
- Gleiter CH, Mörike KE. Clinical pharmacokinetics of candesartan. Clin Pharmacokinet 2002 · PubMed 11825094
- Clausen MV, Hilbers F, Poulsen H. The Structure and Function of the Na,K-ATPase Isoforms in Health and Disease. Front Physiol 2017 · PubMed 28634454
- Berridge MJ, Bootman MD, Roderick HL. Calcium signalling: dynamics, homeostasis and remodelling. Nat Rev Mol Cell Biol 2003 · PubMed 12838335
- US prescribing information (United States): Candesartan Cilexetil Tablets, DailyMed, version of 9 Sept 2026, sections 11 Description, 12.1 Mechanism of Action, 12.2 Pharmacodynamics and 12.3 Pharmacokinetics · Prescribing information
- US prescribing information (United States): Candesartan Cilexetil Tablets, DailyMed, version of 9 Sept 2026, sections 6.1 Clinical Studies Experience and 6.2 Postmarketing Experience · Prescribing information
Related pathways
- Ramipril — angiotensinogen
- Amlodipine — calcium in the cell
As of 2026-09-25. Draft, written by Claude to schema v2; sources checked in PubMed; expert approval pending
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