Candesartan cilexetil: Ester prodrug of candesartan (AT1 receptor antagonist)
Candesartan cilexetil is an ester prodrug of candesartan, an angiotensin II receptor antagonist of the AT1 receptor subgroup (sartan). In all marketed pharmaceutical products, the active ingredient is present in prodrug form because free acid candesartan is poorly absorbed orally. Well-known brand names include Atacand, Blopress, and numerous generics. A comprehensive pillar page on the active ingredient candesartan can be found at /wirkstoff/candesartan.
Candesartan was one of the first sartans to be tested in large endpoint studies (CHARM, RESOLVD, SCOPE) for heart failure, hypertension, and secondary prevention after stroke. Today it is one of the most frequently prescribed sartans in Germany and is standard for essential hypertension and chronic heart failure with reduced ejection fraction (HFrEF), as an alternative or supplement to ACE inhibitors.
Mechanism of action and prodrug concept
Candesartan cilexetil is a cilexetil ester of candesartan. During absorption through the intestinal wall, the cilexetil ester is cleaved by non-specific esterases, allowing free acid candesartan to circulate in the blood. This prodrug form was chosen because candesartan in free form has very poor oral absorption (bioavailability below 5 percent), while candesartan cilexetil achieves an orally available bioavailability of approximately 40 percent.
In the blood, candesartan binds competitively and with high affinity to the angiotensin II type 1 receptor (AT1) and blocks the action of angiotensin II at this site. This leads to vasodilation, reduced aldosterone secretion, improved natriuresis, and reduced end-organ damage from the activated renin angiotensin aldosterone system.
Unlike ACE inhibitors, candesartan does not inhibit bradykinin formation, which is why the typical ACE inhibitor cough rarely occurs with sartans. Candesartan is characterized by a particularly long half-life of approximately 9 hours with firm binding to the receptor, enabling once-daily administration with consistent 24-hour effect.
Indications
- Essential arterial hypertension: first-line therapy or in combination with diuretics and calcium antagonists
- Chronic heart failure with reduced LVEF: in case of ACE inhibitor intolerance or as a supplement
- Diabetic nephropathy: reduction of proteinuria and slowing progression
- Secondary prevention after stroke: as a blood pressure lowering measure
- Off label: migraine prophylaxis (effective in some studies)
Dosage and administration
Hypertension in adults: Initial dose 8 mg once daily, increase to 16 or 32 mg after 2 to 4 weeks depending on blood pressure. Maximum dose 32 mg daily.
Heart failure: Initial dose 4 mg once daily, gradual increase every 2 weeks to target dose 32 mg daily.
Renal impairment: careful dose adjustment if eGFR below 30 ml/min. Contraindicated in bilateral renal artery stenosis.
Hepatic impairment: dose reduction in moderate insufficiency, contraindicated in severe insufficiency with cholestasis.
Administration: with or without food, time of day can be chosen individually but should remain consistent.
Side effects
Common: dizziness, headaches, hypotension (especially with first dose), fatigue, hyperkalemia, slight increase in creatinine.
Occasional: nausea, abdominal pain, diarrhea, pruritus, rash, back pain.
Serious, rare: acute renal failure especially in dehydrated patients or bilateral renal artery stenosis; pronounced hyperkalemia with arrhythmia risk; angioedema (significantly rarer than with ACE inhibitors); cholestatic hepatitis.
Important: Sartans in combination with other RAS inhibitors (ACE inhibitor plus ARB plus aliskiren) can lead to dual or triple RAS blockade, which increases the risk of hyperkalemia and renal insufficiency and is usually not recommended.
Drug interactions
- ACE inhibitors and aliskiren: additive hyperkalemia and renal function deterioration, combination usually not recommended
- Potassium-sparing diuretics (spironolactone, eplerenone, triamterene): additive hyperkalemia, close potassium monitoring
- Potassium supplements and salt substitutes containing potassium: additive hyperkalemia
- NSAIDs: reduced antihypertensive effect and additive nephrotoxicity
- Lithium: elevated lithium levels, level monitoring
- Trimethoprim: additive hyperkalemia
Special notes
Pregnancy: contraindicated. Sartans can cause severe fetal damage in the second and third trimester (renal hypoplasia, anhydramnios, skull malformations, pulmonary hypoplasia, death). Women of childbearing age require reliable contraception. Breast-feeding: not recommended, prefer alternative antihypertensive agents such as methyldopa or beta blockers.
Before starting therapy: creatinine, electrolytes, especially potassium, blood pressure in standing and lying position.
Monitoring: creatinine and potassium 1 to 2 weeks after therapy initiation or dose change, then every 3 to 6 months. If creatinine increases by more than 30 percent or potassium exceeds 5.5 mmol/L, review therapy.
With volume depletion: elderly patients or those on high-dose diuretic therapy may respond with pronounced hypotension to the first dose. Careful dose titration and possible volume replacement are recommended.
Aliskiren combination: in patients with diabetes mellitus or renal impairment, the combination of sartan plus aliskiren is contraindicated due to increased risk of hyperkalemia and acute renal failure.
You might also be interested in
- Candesartan, comprehensive pillar page on the active ingredient
- Valsartan, another sartan
- Losartan, classic sartan
- Ramipril, ACE inhibitor as alternative
- Amlodipine, calcium antagonist as combination partner
Frequently asked questions
What is the difference between candesartan and candesartan cilexetil?
Candesartan is the free acid form that is active in the body. Candesartan cilexetil is the cilexetil ester (prodrug), which is necessary because the free acid is poorly absorbed orally. During absorption, the ester is cleaved, allowing the active form to circulate in the blood. Pharmacologically, the effect is the same, and in clinical practice both terms are used interchangeably.
How quickly does candesartan work for high blood pressure?
A blood pressure reduction is measurable within the first few days, with full effect developing over 4 to 6 weeks. Due to the long half-life, the antihypertensive effect lasts 24 hours, so once-daily administration is sufficient.
Why don't I get a cough with candesartan?
ACE inhibitors inhibit the ACE enzyme, which also breaks down bradykinin. Accumulation of bradykinin in the bronchi causes the typical ACE inhibitor cough in approximately 10 to 20 percent of patients. Sartans like candesartan instead directly block the AT1 receptor, do not affect bradykinin, and therefore do not cause irritant cough.
Can I take candesartan during pregnancy?
No. Sartans are contraindicated in pregnancy due to serious fetal damage. Women of childbearing age should use reliable contraception while taking sartan therapy and should immediately inform their healthcare provider if they wish to become pregnant or if pregnancy occurs, so they can be switched to alternative antihypertensive agents (methyldopa, labetalol, nifedipine).
Sources
- EMA, Atacand (Candesartan cilexetil) EPAR
- ESC ESH guideline arterial hypertension and heart failure
- Gelbe Liste, Candesartan active ingredient profile
- BfArM, Federal Institute for Drugs and Medical Devices
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