CANDESARTAN CILEXETIL; HYDROCHLOROTHIAZIDE
Clinical safety rating: safe
Other antihypertensive drugs can have additive effects Lithium levels may be increased Can cause hypokalemia and hyponatremia.
Candesartan cilexetil is a prodrug that is hydrolyzed to candesartan, an angiotensin II receptor blocker (ARB) that selectively antagonizes the AT1 receptor, inhibiting vasoconstriction and aldosterone secretion. Hydrochlorothiazide is a thiazide diuretic that inhibits the Na+/Cl- cotransporter in the distal convoluted tubule, reducing sodium and water reabsorption.
| Metabolism | Candesartan cilexetil is hydrolyzed by esterases to active candesartan, then O-deethylated by CYP2C9 to inactive metabolites. Hydrochlorothiazide is not extensively metabolized; minor hepatic metabolism. |
| Excretion | Candesartan: 33% renal, 67% biliary/fecal. Hydrochlorothiazide: ≥95% renal (unchanged). |
| Half-life | Candesartan: ~9 hours (terminal); Hydrochlorothiazide: 6–15 hours (terminal). Both support once-daily dosing. |
| Protein binding | Candesartan: >99% (albumin); Hydrochlorothiazide: 68% (albumin). |
| Volume of Distribution | Candesartan: 0.13 L/kg; Hydrochlorothiazide: 3–8 L/kg (extensive tissue distribution). |
| Bioavailability | Candesartan cilexetil: 15% (prodrug, converted to candesartan; absolute); Hydrochlorothiazide: 65–75% (oral). |
| Onset of Action | Candesartan: 2–4 hours (oral); Hydrochlorothiazide: 2 hours (oral). |
| Duration of Action | Candesartan: >24 hours (antihypertensive effect); Hydrochlorothiazide: 12–24 hours (diuretic effect). |
Initial dose: 1 tablet (candesartan cilexetil 16 mg / hydrochlorothiazide 12.5 mg) orally once daily; titrate based on response to maximum dose of 32 mg/25 mg once daily.
| Dosage form | TABLET |
| Renal impairment | Contraindicated if GFR <30 mL/min/1.73 m2. For GFR 30-60 mL/min/1.73 m2: initial dose candesartan cilexetil 8 mg with hydrochlorothiazide 12.5 mg once daily; monitor renal function and electrolytes. No adjustment needed for GFR >60 mL/min/1.73 m2. |
| Liver impairment | In moderate hepatic impairment (Child-Pugh class B): initial candesartan cilexetil dose should not exceed 8 mg once daily. Avoid use in severe hepatic impairment (Child-Pugh class C). Hydrochlorothiazide should be used with caution, with dose adjustment as needed based on response and electrolyte monitoring. |
| Pediatric use | Not recommended in pediatric patients due to lack of safety and efficacy data. Alternative antihypertensive agents are preferred. |
| Geriatric use | Initiate at lower end of dosing range (candesartan cilexetil 8 mg / hydrochlorothiazide 12.5 mg orally once daily) due to increased risk of renal impairment and electrolyte disturbances; titrate slowly and monitor blood pressure, renal function, and serum electrolytes closely. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Other antihypertensive drugs can have additive effects Lithium levels may be increased Can cause hypokalemia and hyponatremia.
| FDA category | Animal |
| Breastfeeding | Candesartan: Minimal excretion in breast milk, M/P ratio unknown but likely low; manufacturer recommends caution. Hydrochlorothiazide: Excreted in breast milk in low amounts, M/P ratio approximately 0.8; may suppress lactation and cause infant electrolyte disturbances; generally not recommended. |
| Teratogenic Risk |
■ FDA Black Box Warning
Drugs that act directly on the renin-angiotensin system (including candesartan) can cause injury and death to the developing fetus. Discontinue as soon as pregnancy is detected.
| Common Effects | edema |
| Serious Effects |
Anuria, hypersensitivity to sulfonamide-derived drugs (hydrochlorothiazide) or candesartan, pregnancy, severe renal impairment (CrCl <30 mL/min), concomitant use with aliskiren in patients with diabetes
| Precautions | Fetal toxicity, hypotension in volume-depleted patients, renal function deterioration (especially with bilateral renal artery stenosis), electrolyte imbalances (hypokalemia, hyponatremia, hypercalcemia), acute angle-closure glaucoma (sulfonamide component), fluid/electrolyte monitoring. |
| Food/Dietary |
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| First trimester: Possible risk of fetal renal impairment and oligohydramnios due to candesartan. Second and third trimesters: Known fetal toxicity including oligohydramnios, fetal renal dysfunction, skull ossification defects, and neonatal hypotension; hydrochlorothiazide may cause fetal electrolyte disturbances and jaundice. |
| Fetal Monitoring | Monitor maternal blood pressure, renal function (serum creatinine, BUN), electrolytes (potassium, sodium), and fetal growth and amniotic fluid volume via ultrasound; assess for oligohydramnios if candesartan used in second/third trimester. |
| Fertility Effects | No direct effects on fertility reported; candesartan and hydrochlorothiazide are not known to impair fertility in humans. |
| High-potassium foods (bananas, oranges, spinach) should be consumed in moderation; avoid potassium supplements and salt substitutes. Grapefruit juice may alter candesartan metabolism; limit intake. Limit alcohol to prevent hypotension. |
| Clinical Pearls | Monitor serum potassium closely, especially in elderly, renal impairment, or those on NSAIDs. Dual blockade with ACE inhibitors increases hyperkalemia risk. Onset of action for candesartan is gradual, taking up to 4 weeks for full effect. |
| Patient Advice | Take exactly as prescribed, usually once daily. · Avoid salt substitutes containing potassium chloride. · Report symptoms of dizziness, lightheadedness, or signs of electrolyte imbalance. · Do not discontinue abruptly; consult provider for dosage adjustments. · May cause dry cough, but less common than with ACE inhibitors. |