Candesartan
Is It Right for You?
A complete guide to Candesartan — what it treats, how it works, dosages, side effects, and when a clinician may prescribe it following an online consultation.
What Is Candesartan?
Candesartan cilexetil (commonly referred to simply as candesartan) is an angiotensin II receptor blocker (ARB) — a class of antihypertensive and cardioprotective medication that works by blocking the effects of angiotensin II on blood vessels and the heart. It is available in tablets of 4 mg, 8 mg, 16 mg, and 32 mg.
Candesartan is widely prescribed in the UK for hypertension and heart failure, and is often used as a first-line alternative to ACE inhibitors — particularly in patients who develop the persistent dry cough that is a common side effect of ACE inhibitor therapy. It is well tolerated, has a long duration of action enabling once-daily dosing, and has an established evidence base for reducing cardiovascular morbidity and mortality in at-risk populations.
Candesartan is a prescription-only medication in the UK. A clinician must assess your blood pressure, renal function, electrolyte levels, and cardiovascular history before it can be prescribed.
What Conditions Is Candesartan Used For?
Candesartan is indicated for:
first- or second-line treatment for primary hypertension in adults; also used in children aged 1–17 years with hypertension
to reduce the risk of cardiovascular death and hospitalisation in patients with left ventricular systolic dysfunction (ejection fraction ≤40%), either as an add-on to ACE inhibitors or as an alternative in ACE-intolerant patient.
used off-label and in clinical practice for renoprotection in patients with type 2 diabetes and proteinuria, slowing progression of kidney disease
Candesartan is an effective antihypertensive but must usually be taken indefinitely. Stopping treatment without medical advice typically results in blood pressure returning to pre-treatment levels. Lifestyle measures — including reduced salt intake, regular exercise, healthy weight, and reduced alcohol consumption — are essential complements to drug therapy.
How Does Candesartan Work?
Candesartan is a prodrug (candesartan cilexetil) that is completely hydrolysed to its active form, candesartan, during absorption from the gastrointestinal tract. It acts as a selective, competitive antagonist at the angiotensin II type 1 (AT1) receptor.
Angiotensin II is a potent vasoconstrictor peptide produced by the renin-angiotensin-aldosterone system (RAAS). When angiotensin II binds to AT1 receptors in vascular smooth muscle, the adrenal cortex, and the kidneys, it causes vasoconstriction, aldosterone release (promoting sodium and water retention), and sympathetic nervous system activation — all of which raise blood pressure and increase cardiac workload.
By blocking the AT1 receptor, candesartan prevents these effects: blood vessels dilate, aldosterone secretion is suppressed, sodium and water excretion is promoted, and blood pressure falls. Unlike ACE inhibitors, ARBs do not inhibit the breakdown of bradykinin, which explains why they do not cause the bradykinin-mediated dry cough seen with ACE inhibitors — a significant tolerability advantage.
Candesartan also has beneficial effects on cardiac remodelling in heart failure by reducing the pathological hypertrophic and fibrotic effects of chronic angiotensin II stimulation on the myocardium.
Dosages & Administration
The correct dose depends on the type and severity of infection, age, weight, and kidney function. Always follow your clinician's instructions. The table below is for general reference only.
Administration Tips
Can be taken with or without food. Food does not significantly affect absorption.
Take at the same time each day. Candesartan's long half-life (approximately 9 hours) supports once-daily dosing with consistent blood pressure control throughout the 24-hour period.
Do not stop suddenly without medical advice. Abrupt discontinuation can cause blood pressure to rebound rapidly.
Start low in heart failure. Initiation in heart failure patients requires careful up-titration with close monitoring of blood pressure, renal function, and potassium levels, particularly in the first 1–2 weeks.
Monitor for dizziness on first doses. First-dose hypotension can occur, particularly in volume-depleted patients. Take initial doses in the evening if concerned.
Side Effects of Candesartan
Most side effects are mild and resolve on their own. Serious side effects are rare but require immediate medical attention.
- Dizziness or lightheadedness (especially on standing — orthostatic hypotension)
- Headache
- Respiratory tract infection (nasopharyngitis)
- Back pain
- Hyperkalaemia (elevated potassium)
- Acute kidney injury
- Severe hyperkalaemia
- Severe hypotension
- Angioedema
- Hepatotoxicity
Candesartan reduces intraglomerular pressure and can cause acute deterioration of renal function in susceptible patients. Renal function (eGFR) and serum potassium must be checked before initiation and within 1–2 weeks of starting treatment or following any dose change.
Drug Interactions
Candesartan may interact with other medications, including potassium-sparing diuretics and NSAIDs. Always inform your clinician about all medications you are taking.
dual RAAS blockade with aliskiren and an ARB is contraindicated in these groups due to increased risk of renal failure, hyperkalaemia, and hypotension.
dual RAAS blockade increases the risk of hypotension, hyperkalaemia, and renal impairment without meaningful additional benefit in most patients; avoid unless specialist-directed.
NSAIDs blunt the antihypertensive effect of candesartan and increase the risk of acute kidney injury, particularly in elderly or volume-depleted patients.
increases the risk of first-dose hypotension; beneficial combination in hypertension and heart failure but requires monitoring.
Important Warnings
Candesartan is contraindicated during pregnancy. ARBs cause fetal harm — including fetal renal dysgenesis, oligohydramnios, skull hypoplasia, limb contractures, and fetal death — when used during the second and third trimester. Women of childbearing potential must use effective contraception. If pregnancy occurs during treatment, candesartan must be stopped immediately and a clinician contacted.
Candesartan is contraindicated in patients with bilateral renal artery stenosis (or stenosis of the artery to a single functioning kidney) due to the risk of severe acute kidney injury.
Use with caution in patients with pre-existing renal impairment; monitor renal function and electrolytes closely. Candesartan is generally avoided in patients with eGFR <15 mL/min.
Candesartan increases potassium retention; risk is amplified by renal impairment, diabetes, concurrent potassium-sparing drugs, or potassium supplementation. Regular monitoring is required.
Speak to a Clinician About Treatment
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The treatment you need, when you need it.
Candesartan FAQs
Candesartan is often prescribed when patients cannot tolerate ACE inhibitors — most commonly because of the persistent dry cough ACE inhibitors can cause. Both drug classes are similarly effective for blood pressure and heart failure but ARBs do not inhibit bradykinin breakdown and therefore rarely cause cough.
Candesartan begins to lower blood pressure within 2 hours of the first dose, but maximal blood pressure reduction is usually seen after 4–6 weeks of regular treatment as the RAAS system reaches a new equilibrium.
Yes. Renal function (eGFR, creatinine) and serum potassium should be checked before starting, 1–2 weeks after initiation or any dose change, and annually thereafter in stable patients. More frequent monitoring is required in patients with renal impairment.
NSAIDs including ibuprofen should be avoided if possible. They reduce the antihypertensive effect of candesartan and, when combined with an ARB, significantly increase the risk of acute kidney injury — particularly in older patients or those who are unwell or dehydrated.
Candesartan is frequently used in patients with diabetes, particularly for its renoprotective effects in diabetic nephropathy. However, diabetic patients are at higher risk of hyperkalaemia when using ARBs, so close potassium monitoring is required.