Exforge can cause fetal harm when administered to a pregnant woman. Use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Most epidemiologic studies examining fetal abnormalities after exposure to antihypertensive use in the first trimester have not distinguished drugs affecting the renin-angiotensin system from other antihypertensive agents. Published reports include cases of anhydramnios and oligohydramnios in pregnant women treated with valsartan (see Clinical Considerations).
When pregnancy is detected, discontinue EXFORGE as soon as possible.
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.
Disease-Associated Maternal and/or Embryo/Fetal risk
Hypertension in pregnancy increases the maternal risk for pre-eclampsia, gestational diabetes, premature delivery, and delivery complications (e.g., need for cesarean section, and post-partum hemorrhage). Hypertension increases the fetal risk for intrauterine growth restriction and intrauterine death. Pregnant women with hypertension should be carefully monitored and managed accordingly.
Fetal/Neonatal Adverse Reactions
Oligohydramnios in pregnant women who use drugs affecting the renin-angiotensin system in the second and third trimesters of pregnancy can result in the following: reduced fetal renal function leading to anuria and renal failure, fetal lung hypoplasia, skeletal deformations, including skull hypoplasia, hypotension and death.
Perform serial ultrasound examinations to assess the intra-amniotic environment. Fetal testing may be appropriate, based on the week of gestation. Patients and physicians should be aware, however, that oligohydramnios may not appear until after the fetus has sustained irreversible injury. If oligohydramnios is observed, consider alternative drug treatment. Closely observe neonates with histories of in utero exposure to Exforge for hypotension, oliguria, and hyperkalemia. In neonates with a history of in utero exposure to Exforge, if oliguria or hypotension occurs, support blood pressure and renal perfusion. Exchange transfusions or dialysis may be required as a means of reversing hypotension and replacing renal function.
In rats, administered 20 mg/kg/day amlodipine plus 320 mg/kg/day valsartan, treatment-related maternal and fetal effects (developmental delays and alterations noted in the presence of significant maternal toxicity) were noted with the high dose combination. This corresponds to dose multiples of 9 and 19.5 times, respectively, the maximum recommended human dose (MRHD) of 10 mg/day for amlodipine and 320 mg/day for valsartan (based on body surface area and considering a 60 kg patient).
There is limited information regarding the presence of Exforge in human milk, the effects on the breastfed infant, or the effects on milk production. Valsartan is present in rat milk. Limited published studies report that amlodipine is present in human milk. Because of the potential for serious adverse reactions in breastfed infants, advise a nursing woman that breastfeeding is not recommended during treatment with Exforge.
Valsartan was detected in the milk of lactating rats 15 minutes after oral administration of a 3 mg/kg dose.
Safety and effectiveness of Exforge in pediatric patients have not been established.
In controlled clinical trials, 323 (22.5%) hypertensive patients treated with Exforge were ≥ 65 years and 79 (5.5%) were ≥ 75 years. No overall differences in the efficacy or safety of Exforge was observed in this patient population, but greater sensitivity of some older individuals cannot be ruled out.
Amlodipine: The recommended starting dose of amlodipine 2.5 mg is not an available strength with Exforge.
Clinical studies of amlodipine besylate tablets did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy. Elderly patients have decreased clearance of amlodipine with a resulting increase of area under the curve (AUC) of approximately 40% to 60%.
Valsartan: In the controlled clinical trials of valsartan, 1214 (36.2%) of hypertensive patients treated with valsartan were ≥ 65 years and 265 (7.9%) were ≥ 75 years. No overall difference in the efficacy or safety of valsartan was observed in this patient population, but greater sensitivity of some older individuals cannot be ruled out.
Safety and effectiveness of Exforge in patients with severe renal impairment (CrCl < 30 mL/min) have not been established. No dose adjustment is required in patients with mild (CrCl 60 to 90 mL/min) or moderate (CrCl 30 to 60 mL/min) renal impairment.
Exposure to amlodipine is increased in patients with hepatic insufficiency [see Clinical Pharmacology (12.3)]. The recommended initial dose of amlodipine in patients with hepatic impairment is 2.5 mg, which is not an available strength with Exforge.
No dose adjustment is necessary for patients with mild-to-moderate disease. No dosing recommendations can be provided for patients with severe liver disease.
Single oral doses of amlodipine maleate equivalent to 40 mg/kg and 100 mg/kg amlodipine in mice and rats, respectively, caused deaths. Single oral doses equivalent to 4 or more mg/kg amlodipine in dogs (11 or more times the maximum recommended human dose on a mg/m2 basis) caused a marked peripheral vasodilation and hypotension.
Overdosage might be expected to cause excessive peripheral vasodilation with marked hypotension. In humans, experience with intentional overdosage of amlodipine is limited. Marked and potentially prolonged systemic hypotension up to and including shock with fatal outcome have been reported.
If massive overdose should occur, initiate active cardiac and respiratory monitoring. Frequent blood pressure measurements are essential. Should hypotension occur, cardiovascular support including elevation of the extremities and the judicious administration of fluids should be initiated. If hypotension remains unresponsive to these conservative measures, consider administration of vasopressors (such as phenylephrine) with attention to circulating volume and urine output. As amlodipine is highly protein bound, hemodialysis is not likely to be of benefit. Administration of activated charcoal to healthy volunteers immediately or up to two hours after ingestion of amlodipine has been shown to significantly decrease amlodipine absorption.
Limited data are available related to overdosage in humans. The most likely effect of overdose with valsartan would be peripheral vasodilation, hypotension, and tachycardia; bradycardia could occur from parasympathetic (vagal) stimulation. Depressed level of consciousness, circulatory collapse, and shock have been reported. If symptomatic hypotension should occur, institute supportive treatment.
Valsartan is not removed from the plasma by hemodialysis.
Valsartan was without grossly observable adverse effects at single oral doses up to 2000 mg/kg in rats and up to 1000 mg/kg in marmosets, except for the salivation and diarrhea in the rat and vomiting in the marmoset at the highest dose (60 and 37 times, respectively, the MRHD on a mg/m2 basis) (Calculations assume an oral dose of 320 mg/day and a 60 kg patient).
Exforge is a fixed combination of amlodipine and valsartan.
Exforge contains the besylate salt of amlodipine, a dihydropyridine calcium-channel blocker (CCB). Amlodipine besylate is a white to pale yellow crystalline powder, slightly soluble in water and sparingly soluble in ethanol. Amlodipine besylate’s chemical name is 3-Ethyl-5-methyl(4RS)-2-[(2-aminoethoxy)methyl]-4-(2-chlorophenyl)-6-methyl-1,4-dihydropyridine-3,5-dicarboxylate benzenesulphonate; its structural formula is:
Its empirical formula is C20 H25 ClN2 O5 •C6 H6 O3 S and its molecular weight is 567.1.
Valsartan is a nonpeptide, orally active, and specific angiotensin II antagonist acting on the AT1 receptor subtype. Valsartan is a white to practically white fine powder, soluble in ethanol and methanol and slightly soluble in water. Valsartan’s chemical name is N-(1-oxopentyl)-N-[[2’-(1H-tetrazol-5-yl) [1,1’-biphenyl]-4-yl]methyl]-L-valine; its structural formula is:
Its empirical formula is C24 H29 N5 O3 and its molecular weight is 435.5.
Exforge tablets are formulated in 4 strengths for oral administration with a combination of amlodipine besylate (6.9 mg or 13.9 mg, equivalent to 5 mg or 10 mg of amlodipine respectively), with 160 mg, or 320 mg of valsartan providing for the following available combinations: 5/160 mg, 10/160 mg, 5/320 mg, and 10/320 mg.
The inactive ingredients for all strengths of the tablets are colloidal silicon dioxide, crospovidone, magnesium stearate, and microcrystalline cellulose. Additionally the 5/320 mg and 10/320 mg strengths contain iron oxide yellow and sodium starch glycolate. The film coating contains hypromellose, iron oxides, polyethylene glycol, talc, and titanium dioxide.
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