EXFORGE HCT
Clinical safety rating
cautionComprehensive clinical and safety monograph for EXFORGE HCT (EXFORGE HCT).
EXFORGE HCT is a combination of amlodipine (a dihydropyridine calcium channel blocker), valsartan (an angiotensin II receptor blocker), and hydrochlorothiazide (a thiazide diuretic). Amlodipine inhibits calcium ion influx across cardiac and vascular smooth muscle cells, leading to vasodilation. Valsartan blocks the vasoconstrictor and aldosterone-secreting effects of angiotensin II. Hydrochlorothiazide increases excretion of sodium and water by inhibiting the Na+/Cl- symporter in the distal convoluted tubule.
| Metabolism | Amlodipine is extensively metabolized in the liver via CYP3A4; valsartan is minimally metabolized (about 20%) via CYP2C9; hydrochlorothiazide is not metabolized and is excreted unchanged. |
| Excretion | Valsartan: 13% excreted unchanged in urine, 83% in feces via biliary secretion. Amlodipine: 10% excreted unchanged in urine, 60% as metabolites in urine, 20-25% in feces. Hydrochlorothiazide: ≥95% excreted unchanged in urine. |
| Half-life | Valsartan: 6 hours (terminal). Amlodipine: 30-50 hours (terminal), permits once-daily dosing. Hydrochlorothiazide: 6-15 hours (terminal). |
| Protein binding | Valsartan: 94-97% (primarily albumin). Amlodipine: ~93% (albumin). Hydrochlorothiazide: 40-68% (albumin). |
| Volume of Distribution | Valsartan: 17 L (0.24 L/kg); indicates limited extravascular distribution. Amlodipine: 21 L/kg; extensive tissue distribution. Hydrochlorothiazide: 3-15 L (0.05-0.2 L/kg); distributes into extracellular fluid. |
| Bioavailability | Oral: Valsartan 25% (wide range 10-35%), amlodipine 64-90%, hydrochlorothiazide 65-75%. |
| Onset of Action | Oral: Antihypertensive effect begins within 2 hours for valsartan and amlodipine; diuretic effect of HCTZ begins within 2 hours. |
| Duration of Action | Valsartan: 24 hours. Amlodipine: 24 hours. Hydrochlorothiazide: 12-16 hours; combined effect provides 24-hour blood pressure control. |
| Molecular Weight | Valsartan: 435.5 Da; Amlodipine: 408.9 Da; Hydrochlorothiazide: 297.7 Da |
One tablet orally once daily. Initial dose based on previous antihypertensive therapy; maximum dose is one tablet of 10 mg amlodipine/320 mg valsartan/25 mg hydrochlorothiazide per day.
| Dosage form | TABLET |
| Renal impairment | Contraindicated in anuria. For GFR 30-60 mL/min: no dose adjustment needed, but monitor serum potassium and creatinine. For GFR <30 mL/min: not recommended due to limited data. |
| Liver impairment | Child-Pugh Class A: no adjustment; Class B: maximum dose 5 mg amlodipine/160 mg valsartan/12.5 mg hydrochlorothiazide; Class C: not recommended. |
| Pediatric use | Safety and efficacy in pediatric patients (<18 years) have not been established; no recommended dosing. |
| Geriatric use | Initiate at the lowest available dose (5 mg amlodipine/160 mg valsartan/12.5 mg hydrochlorothiazide) and titrate slowly; monitor renal function, electrolytes, and blood pressure due to increased risk of hypotension and electrolyte imbalance. |
| 1st trimester | Use is not recommended due to risk of fetal toxicity from the angiotensin receptor blocker (valsartan) and potential teratogenicity from angiotensin II receptor antagonists; avoid if possible. |
| 2nd trimester | Contraindicated in pregnancy due to fetal renal dysfunction, oligohydramnios, skull ossification defects, and neonatal hypotension from valsartan; hydrochlorothiazide may cause fetal electrolyte disturbances. |
| 3rd trimester | Contraindicated in pregnancy as above; oligohydramnios may cause fetal limb contractures, craniofacial deformities, and pulmonary hypoplasia. |
Clinical note
Comprehensive clinical and safety monograph for EXFORGE HCT (EXFORGE HCT).
| Placental transfer | Valsartan and hydrochlorothiazide are known to cross the placenta in humans; amlodipine is expected to cross based on animal studies. Fetal exposure is significant, especially in the second and third trimesters. |
| Breastfeeding | Valsartan and hydrochlorothiazide are excreted in human milk; amlodipine is excreted in small amounts. Use during breastfeeding is not recommended due to potential adverse effects in the infant, including electrolyte disturbances from hydrochlorothiazide and possible hypotension from amlodipine/valsartan. Alternative agents are preferred. |
| Lactation Rating | Avoid |
| Teratogenic Risk | First trimester: Drugs acting on renin-angiotensin system (ARB/ACEi component: valsartan) associated with increased risk of fetal renal dysfunction, oligohydramnios, skull ossification defects, and fetal death if exposed during first trimester. However, major teratogenic risk is primarily second and third trimester. Hydrochlorothiazide (HCTZ) may cause fetal or neonatal jaundice, thrombocytopenia, and electrolyte disturbances. Second and third trimester: Valsartan exposure is associated with oligohydramnios, fetal renal failure, skull hypoplasia, anuria, and death. HCTZ can cause fetal electrolyte imbalances, jaundice, and thrombocytopenia. Avoid use in pregnancy, especially second and third trimesters. |
| Fetal Monitoring | If exposed during pregnancy, monitor amniotic fluid index, fetal renal function (ultrasound for oligohydramnios), fetal growth, and blood pressure. Assess maternal renal function and electrolytes. In newborns, monitor for hypotension, oliguria, hyperkalemia, and electrolyte imbalances. |
| Fertility Effects | No specific studies on Exforge HCT. ARBs/ACE inhibitors may rarely cause reversible erectile dysfunction. HCTZ may rarely affect spermatogenesis. No known significant impact on female fertility. |
■ FDA Black Box Warning
WARNING: FETAL TOXICITY. Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus. Discontinue as soon as possible once pregnancy is detected.
| Serious Effects |
PregnancyAnuria (from hydrochlorothiazide component)Hypersensitivity to any component (valsartan, amlodipine, hydrochlorothiazide) or sulfonamide-derived drugs (hydrochlorothiazide is a sulfonamide)Concomitant use with aliskiren in patients with diabetes mellitus
| Precautions | Fetal toxicity: avoid use in pregnancy; discontinue if pregnancy occurs., Hypotension: symptomatic hypotension may occur, especially in volume-depleted patients., Electrolyte and metabolic effects: hydrochlorothiazide may cause hypokalemia, hyponatremia, hypercalcemia, hypomagnesemia, and hyperglycemia., Renal function deterioration: monitor renal function; may cause acute renal failure., Hepatic impairment: use caution in patients with severe hepatic impairment., Angioedema: reported with valsartan; monitor for swelling of face, lips, throat., Avoid concomitant use with aliskiren in patients with diabetes or renal impairment. |
| Food/Dietary | Avoid high-potassium foods (bananas, oranges, spinach, potatoes) and salt substitutes with potassium unless instructed otherwise. Grapefruit juice may increase amlodipine levels; limit consumption. Alcohol may enhance hypotensive effects. Maintain adequate fluid intake to prevent dehydration. |
| Clinical Pearls | Exforge HCT is a triple combination of amlodipine, valsartan, and hydrochlorothiazide. It is indicated for hypertension not adequately controlled on dual therapy. Monitor serum potassium, especially in patients with renal impairment or on NSAIDs. Avoid use in pregnancy due to direct renin-angiotensin system effects. Titrate doses based on blood pressure response. Common side effects include peripheral edema (amlodipine), dizziness, and electrolyte disturbances (HCTZ). |
| Patient Advice | Take exactly as prescribed, usually once daily with or without food. · Do not stop taking this medication without consulting your doctor. · Report any signs of allergic reaction (rash, swelling, difficulty breathing) or low blood pressure (dizziness, fainting). · Avoid potassium supplements or salt substitutes containing potassium unless advised by your doctor. · Limit alcohol intake as it may increase blood pressure or cause dizziness. · If pregnant or planning pregnancy, inform your doctor immediately as this drug can harm an unborn baby. · May cause dizziness or drowsiness; avoid driving until you know how you react. · Stay hydrated to prevent dehydration from hydrochlorothiazide, especially if you sweat heavily or have diarrhea/vomiting. |
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