EXFORGE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for EXFORGE (EXFORGE).
Exforge is a combination of amlodipine, a dihydropyridine calcium channel blocker, and valsartan, an angiotensin II receptor blocker. Amlodipine inhibits calcium influx across cardiac and vascular smooth muscle cell membranes, causing vasodilation. Valsartan selectively blocks the binding of angiotensin II to AT1 receptors, leading to vasodilation and reduced aldosterone secretion.
| Metabolism | Amlodipine is extensively metabolized in the liver via CYP3A4 to inactive metabolites. Valsartan is primarily eliminated unchanged in feces and urine; only about 20% is metabolized by CYP2C9. |
| Excretion | Valsartan is primarily eliminated via biliary excretion (83%) in feces as unchanged drug; renal excretion accounts for 13% (mostly unchanged). Amlodipine is extensively metabolized in the liver, with 60% of metabolites excreted renally and 20-25% in feces as unchanged drug. |
| Half-life | Amlodipine: terminal elimination half-life is 30-50 hours (mean ~35 h), supporting once-daily dosing. Valsartan: terminal half-life is approximately 6 hours, with the combination product dosed once daily due to amlodipine's long half-life. |
| Protein binding | Amlodipine: ~93% bound to plasma proteins. Valsartan: 94-97% bound to serum albumin. |
| Volume of Distribution | Amlodipine: Vd is approximately 21 L/kg, indicating extensive extravascular distribution. Valsartan: Vd is about 17 L, not weight-adjusted, indicating distribution mainly in plasma and extracellular fluid. |
| Bioavailability | Oral bioavailability: Amlodipine 64-90%; Valsartan about 25% (with wide interindividual variability). Food decreases valsartan absorption by about 40-50%, but does not affect amlodipine absorption. |
| Onset of Action | Oral: Antihypertensive effect begins within 2 hours, with maximal effect at 4-8 hours. Clinical onset is typically seen within 1-2 weeks of continuous therapy. |
| Duration of Action | Duration of antihypertensive effect is at least 24 hours with once-daily dosing, due to amlodipine's long half-life and valsartan's sustained receptor blockade. Steady-state is achieved after 7-14 days. |
| Brand Substitutes | Valembic 160 AM Tablet, AMLOPRES-VL 5MG/160MG TABLET, Trivalzaar 5mg/160mg Tablet, AMLOPRES-VL 5MG/80MG TABLET, Valembic 80 AM Tablet, Trivalzaar 80 Tablet |
One tablet orally once daily. Initial dose: 5/160 mg or 5/320 mg. Titrate based on blood pressure response. Maximum dose: 10/320 mg once daily.
| Dosage form | TABLET |
| Renal impairment | For GFR 30-60 mL/min: no adjustment. For GFR <30 mL/min: not recommended due to lack of data. Contraindicated if GFR <30 mL/min due to hydrochlorothiazide component. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: not recommended. Child-Pugh C: contraindicated. |
| Pediatric use | Safety and efficacy not established in pediatric patients below 18 years. |
| Geriatric use | No dose adjustment required based on age alone. Initiate at lower end of dosing range (5/160 mg) due to potential for increased sensitivity to hypotension. Monitor renal function closely. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for EXFORGE (EXFORGE).
| Breastfeeding | No data on Exforge in breast milk. Valsartan is excreted in rat milk; amlodipine is excreted in human milk (M/P ratio unknown). Due to potential adverse effects in nursing infants (hypotension, renal effects), avoid breastfeeding. If used, monitor infant for hypotension and renal function. |
| Teratogenic Risk | Pregnancy Category D. First trimester: Potential fetal toxicity; risk of malformations not significantly increased based on limited data. Second and third trimesters: Oligohydramnios, fetal renal dysfunction, skull ossification defects, hypotension, hyperkalemia, and anuria due to angiotensin II receptor antagonist (valsartan) component. Amlodipine may cause fetal hypoxia due to uterine hypoperfusion. |
■ FDA Black Box Warning
Exforge contains valsartan, which can cause fetal harm when used during pregnancy. If pregnancy is detected, discontinue Exforge as soon as possible.
| Serious Effects |
["Pregnancy","Hypersensitivity to amlodipine, valsartan, or any component of the formulation","Concomitant use with aliskiren in patients with diabetes"]
| Precautions | ["Fetal toxicity","Hypotension in salt- or volume-depleted patients","Impaired renal function","Hyperkalemia","Angioedema","Hepatic impairment","Severe obstructive coronary artery disease"] |
| Food/Dietary | Avoid grapefruit juice (increases amlodipine AUC by 56%). High-potassium foods (bananas, oranges, spinach) may increase hyperkalemia risk; no specific restriction but monitor intake if renal impairment. |
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| Fetal Monitoring | Serial fetal ultrasound to assess amniotic fluid volume and renal function; monitor maternal blood pressure and electrolytes (especially potassium), serum creatinine, and urine output. Fetal heart rate monitoring during labor if used near term. |
| Fertility Effects | No human data on Exforge. In animal studies, no adverse effects on fertility. Valsartan may cause reversible infertility in animals, not confirmed in humans. |
| Clinical Pearls | EXFORGE (amlodipine/valsartan) combines a dihydropyridine calcium channel blocker with an angiotensin II receptor blocker. It is contraindicated in pregnancy (fetal nephrotoxicity, oligohydramnios). Monitor serum potassium and renal function, especially in older adults, volume-depleted patients, or those with renal impairment. Avoid use with aliskiren in patients with diabetes or GFR <60 mL/min. Peripheral edema is less than amlodipine alone due to vasodilation balance. |
| Patient Advice | Do not take if pregnant or planning pregnancy; use effective contraception. · Avoid grapefruit juice as it increases amlodipine levels and risk of hypotension. · Take the same time each day; do not skip doses or double up. · May cause dizziness or lightheadedness; avoid driving until you know how it affects you. · Report swelling in hands/feet, irregular heartbeat, or signs of angioedema (swelling of face/lips). |