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Uses

Amlodipine, valsartan & hydrochlorothiazide is used for the treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. These benefits have been seen in controlled trials of antihypertensive drugs from a wide variety of pharmacologic classes, including amlodipine, hydrochlorothiazide, and the ARB class to which valsartan principally belongs. There are no controlled trials demonstrating risk reduction with Amlodipine, valsartan & hydrochlorothiazide.

exforge hct is also used to associated treatment for these conditions: Anginal Pain, Cardiovascular Events, Chronic Stable Angina Pectoris, Coronary Artery Disease (CAD), High Blood Pressure (Hypertension), Homozygous Familial Hypercholesterolemia, Hypertension,Essential, Mixed Dyslipidemias, Primary Hypercholesterolemia, Vasospastic AnginaAcidosis, Renal Tubular, Calcium Nephrolithiasis, Cirrhosis of the Liver, Congestive Heart Failure (CHF), Diabetes Insipidus, Edema, High Blood Pressure (Hypertension), Hypertension,Essential, Hypokalemia caused by diuretics, Nephrotic Syndrome, Premenstrual tension with edema, Sodium retention, Stroke, Prophylaxis of preeclampsiaCardiovascular Mortality, Diabetic Nephropathy, High Blood Pressure (Hypertension), Left Ventricular Dysfunction, Moderate Essential Hypertension, Chronic heart failure with reduced ejection fraction (NYHA Class II), Chronic heart failure with reduced ejection fraction (NYHA Class III), Chronic heart failure with reduced ejection fraction (NYHA Class IV), Hospitalization due to cardiac failure

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Mechanism of action on blood pressure

Amlodipine is considered a peripheral arterial vasodilator that exerts its action directly on vascular smooth muscle to lead to a reduction in peripheral vascular resistance, causing a decrease in blood pressure. Amlodipine is a dihydropyridine calcium antagonist (calcium ion antagonist or slow-channel blocker) that inhibits the influx of calcium ions into both vascular smooth muscle and cardiac muscle. Experimental studies imply that amlodipine binds to both dihydropyridine and nondihydropyridine binding sites, located on cell membranes. The contraction of cardiac muscle and vascular smooth muscle are dependent on the movement of extracellular calcium ions into these cells by specific ion channels. Amlodipine blocks calcium ion influx across cell membranes with selectivity. A stronger effect of amlodipine is exerted on vascular smooth muscle cells than on cardiac muscle cells . Direct actions of amlodipine on vascular smooth muscle result in reduced blood pressure .

Mechanism of action in angina

The exact mechanism by which amlodipine relieves the symptoms of angina have not been fully elucidated to this date, however, the mechanism of action is likely twofold:

Amlodipine has a dilating effect on peripheral arterioles, reducing the total peripheral resistance (afterload) against which the cardiac muscle functions. Since the heart rate remains stable during amlodipine administration, the reduced work of the heart reduces both myocardial energy use and oxygen requirements .

Dilatation of the main coronary arteries and coronary arterioles, both in healthy and ischemic areas, is another possible mechanism of amlodipine reduction of blood pressure. The dilatation causes an increase in myocardial oxygen delivery in patients experiencing coronary artery spasm (Prinzmetal's or variant angina) and reduces coronary vasoconstriction caused by smoking .

Hydrochlorothiazide is transported from the circulation into epithelial cells of the distal convoluted tubule by the organic anion transporters OAT1, OAT3, and OAT4. From these cells, hydrochlorothiazide is transported to the lumen of the tubule by multidrug resistance associated protein 4 (MRP4).

Normally, sodium is reabsorbed into epithelial cells of the distal convoluted tubule and pumped into the basolateral interstitium by a sodium-potassium ATPase, creating a concentration gradient between the epithelial cell and the distal convoluted tubule that promotes the reabsorption of water.

Hydrochlorothiazide acts on the proximal region of the distal convoluted tubule, inhibiting reabsorption by the sodium-chloride symporter, also known as Solute Carrier Family 12 Member 3 (SLC12A3). Inhibition of SLC12A3 reduces the magnitude of the concentration gradient between the epithelial cell and distal convoluted tubule, reducing the reabsorption of water.

Valsartan belongs to the angiotensin II receptor blocker (ARB) family of drugs, which selectively bind to angiotensin receptor 1 (AT1) and prevent angiotensin II from binding and exerting its hypertensive effects. These include vasoconstriction, stimulation and synthesis of aldosterone and ADH, cardiac stimulation, and renal reabsorption of sodium among others. Overall, valsartan's physiologic effects lead to reduced blood pressure, lower aldosterone levels, reduced cardiac activity, and increased excretion of sodium.

Valsartan also affects the renin-angiotensin aldosterone system (RAAS), which plays an important role in hemostasis and regulation of kidney, vascular, and cardiac functions. Pharmacological blockade of RAAS via AT1 receptor blockade inhibits negative regulatory feedback within RAAS which is a contributing factor to the pathogenesis and progression of cardiovascular disease, heart failure, and renal disease. In particular, heart failure is associated with chronic activation of RAAS, leading to inappropriate fluid retention, vasoconstriction, and ultimately a further decline in left ventricular function. ARBs have been shown to have a protective effect on the heart by improving cardiac function, reducing afterload, increasing cardiac output and prevent ventricular hypertrophy.

The angiotensin-converting enzyme inhibitor (ACEI) class of medications (which includes drugs such as ramipril, lisinopril, and perindopril) inhibits the conversion of angiotensin I to angiotensin II by inhibiting the ACE enzyme but does not prevent the formation of all angiotensin II. ARB activity is unique in that it blocks all angiotensin II activity, regardless of where or how it was synthesized.

Valsartan is commonly used for the management of hypertension, heart failure, and type 2 diabetes-associated nephropathy, particularly in patients who are unable to tolerate ACE inhibitors. ARBs such as valsartan have been shown in a number of large-scale clinical outcomes trials to improve cardiovascular outcomes including reducing risk of myocardial infarction, stroke, the progression of heart failure, and hospitalization. Valsartan also slows the progression of diabetic nephropathy due to its renoprotective effects. Improvements in chronic kidney disease with valsartan include both clinically and statistically significant decreases in urinary albumin and protein excretion in patients diagnosed with type 2 diabetes and in nondiabetic patients diagnosed with chronic kidney disease.

Valsartan also binds to the AT2 receptor, however AT2 is not known to be associated with cardiovascular homeostasis like AT1. Valsartan has about 20,000-fold higher affinity for the AT1 receptor than for the AT2 receptor. The increased plasma levels of angiotensin II following AT1 receptor blockade with valsartan may stimulate the unblocked AT2 receptor.

Dosage

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General Considerations: Dose once-daily. The dosage may be increased after two weeks of therapy. The full blood pressure lowering effect was achieved 2 weeks after being on the maximal dose of Amlodipine, valsartan & hydrochlorothiazide. The maximum recommended dose is Amlodipine 10 mg, valsartan 320 mg & hydrochlorothiazide 25 mg

Add-on or Switch Therapy: Amlodipine, valsartan & hydrochlorothiazide may be used for patients not adequately controlled on any two of the following antihypertensive classes: calcium channel blockers, angiotensin receptor blockers, and diuretics.

A patient who experiences dose-limiting adverse reactions to an individual component while on any dual combination of the components of Amlodipine, valsartan & hydrochlorothiazide may be switched to Amlodipine, valsartan & hydrochlorothiazide containing a lower dose of that component to achieve similar blood pressure reductions.

Replacement Therapy: Amlodipine, valsartan & hydrochlorothiazide may be substituted for the individually titrated components.

Use with Other Antihypertensive Drugs: Amlodipine, valsartan & hydrochlorothiazide may be administered with other antihypertensive agents.

Administration of Valsartan with food decreases the absorption of Valsartan by about 40%, so it should be taken on an empty stomach. No initial dosage adjustment is required for elderly patients with mild to moderate renal and hepatic insufficiency.

Side Effects

Common side effects are Dizziness, Edema, Headache, Dyspepsia, Fatigue, Muscle spasms, Back pain, Nausea, Nasopharyngitis

Toxicity

Acute oral toxicity (LD50): 37 mg/kg (mouse) .

Overdose

An overdose of amlodipine could result in a high degree of peripheral vasodilatation with a possibility of reflex tachycardia. Significant and prolonged hypotension leading to shock and fatal outcomes have been reported .

Carcinogenesis, mutagenesis, impairment of fertility

Rats and mice treated with amlodipine maleate in the diet on a long-term basis for up to 2 years demonstrated no evidence of a carcinogenic effect of the drug. For the mouse, the highest dose was comparable to the maximum recommended human dose of 10 mg amlodipine per day. For the rat, the highest dose was measured to be about twice the maximum recommended human dose .

Mutagenicity studies using amlodipine maleate showed no drug-related gene or chromosomal effects .

There was no impact on the fertility of rats given oral amlodipine maleate (males for 64 days and females for 14 days before mating) at doses up to 10 mg amlodipine/kg/day (8 times the maximum recommended human dose) .

Use in pregnancy

The safety of amlodipine in human pregnancy or lactation has not been proven. Amlodipine is therefore considered a pregnancy category C drug . Use amlodipine only if the potential benefit justifies the potential risk .

Use in nursing

Discontinue when administering amlodipine .

The oral LD₅₀ of hydrochlorothiazide is >10g/kg in mice and rats.

Patients experiencing an overdose may present with hypokalemia, hypochloremia, and hyponatremia. Treat patients with symptomatic and supportive treatment including fluids and electrolytes. Vasopressors may be administered to treat hypotension and oxygen may be given for respiratory impairment.

Approximate LD50 >2000 mg/kg (Gavage, rat) [F3139]

Reproductive Toxicology Studies

No teratogenic effects were seen when valsartan was given to pregnant mice and rats at oral doses up to 600 mg/kg/day and to pregnant rabbits at oral doses reaching up to 10 mg/kg/day. Despite this, marked decreases in fetal weight, pup birth weight, pup survival rate, and delays in developmental milestones were noted in studies in which parental rats were treated with valsartan at oral, maternally toxic doses of 600 mg/kg/day during the organogenesis period or during late gestation and lactation.[F4607]

Pregnancy

When used in pregnancy, drugs that act directly on the renin-angiotensin system (RAAS) can cause injury and death to the developing fetus. When pregnancy is detected, valsartan should be discontinued as soon as possible.[F4607]

Precaution

Increased Angina and/or Myocardial Infarction: Worsening angina and acute myocardial infarction can develop after starting or increasing the dose of amlodipine, particularly in patients with severe obstructive coronary artery disease.

Impaired Renal Function: Changes in renal function including acute renal failure can be caused by drugs that inhibit the renin-angiotensin system and by diuretics. Patients whose renal function may depend in part on the activity of the renin-angiotensin system (e.g., patients with renal artery stenosis, chronic kidney disease, severe congestive heart failure, or volume depletion) may be at particular risk of developing acute renal failure on Amlodipine, valsartan & hydrochlorothiazide. Monitor renal function periodically in these patients. Consider withholding or discontinuing therapy in patients who develop a clinically significant decrease in renal function on Amlodipine, valsartan & hydrochlorothiazide.

Hypotension in Volume- or Salt-Depleted Patients: Excessive hypotension, including orthostatic hypotension, was seen in 1.7% of patients treated with the maximum dose of Amlodipine, valsartan & hydrochlorothiazide (10/320/25 mg) compared to 1.8% of valsartan/HCTZ (320/25 mg) patients, 0.4% of amlodipine/valsartan (10/320 mg) patients, and 0.2% of HCTZ/amlodipine (25/10 mg) patients in a controlled trial in patients with moderate to severe uncomplicated hypertension. In patients with an activated renin-angiotensin system, such as volume- or salt-depleted patients receiving high doses of diuretics, symptomatic hypotension may occur in patients receiving angiotensin receptor blockers. Correct this condition prior to administration of Amlodipine, valsartan & hydrochlorothiazide.

Hypersensitivity Reaction: Hypersensitivity reactions to hydrochlorothiazide may occur in patients with or without a history of allergy or bronchial asthma, but are more likely in patients with such a history.

Interaction

No drug interaction studies have been conducted with Amlodipine, valsartan & hydrochlorothiazide and other drugs, although studies have been conducted with the individual components. A pharmacokinetic drug-drug interaction study has been conducted to address the potential for pharmacokinetic interaction between the triple combination, Amlodipine, valsartan & hydrochlorothiazide, and the corresponding three double combinations. No clinically relevant interaction was observed.

Volume of Distribution

21 L/kg , .

The volume of distribution varies widely from one study to another with values of 0.83-4.19L/kg.

The steady state volume of distribution of valsartan after intravenous administration is small (17 L), indicating that valsartan does not distribute into tissues extensively.[F3139,F3607]

Elimination Route

Amlodipine absorbed slowly and almost completely from the gastrointestinal tract. Peak plasma concentrations are achieved 6-12 hours after oral administration. The estimated bioavailability of amlodipine is 64-90%. Steady-state plasma amlodipine levels are achieved after 7-8 days of consecutive daily dosing. Absorption is not affected by food .

An oral dose of hydrochlorothiazide is 65-75% bioavailable, with a T_max of 1-5 hours, and a C_max of 70-490ng/mL following doses of 12.5-100mg. When taken with a meal, bioavailability is 10% lower, C_max is 20% lower, and T_max increases from 1.6 to 2.9 hours.

After one oral dose, the antihypertensive activity of valsartan begins within approximately 2 hours and peaks within 4-6 hours in most patients.[F3139] Food decreases the exposure to orally administered valsartan by approximately 40% and peak plasma concentration by approximately 50%. AUC and Cmax values of valsartan genereally increase linearly with increasing dose over the therapeutic dose range. Valsartan does not accumulate appreciably in plasma following repetitive administration.[F4607]

Half Life

The terminal elimination half-life of about 30–50 hours .

Plasma elimination half-life is 56 hours in patients with impaired hepatic function, titrate slowly when administering this drug to patients with severe hepatic impairment .

The plasma half life of hydrochlorothiazide is 5.6-14.8h.

After intravenous (IV) administration, valsartan demonstrates bi-exponential decay kinetics, with an average elimination half-life of about 6 hours.[F4607]

Clearance

Total body clearance (CL) has been calculated as 7 ± 1.3 ml/min/kg (0.42 ± 0.078 L/ h/kg) in healthy volunteers , .

Elderly patients show a reduced clearance of amlodipine with an AUC (area under the curve) increase of about 40–60%, and a lower initial dose may be required .

The renal clearance of hydrochlorothiazide in patients with normal renal function is 285mL/min. Patients with a creatinine clearance of 31-80mL/min have an average hydroxychlorothiazide renal clearance of 75mL/min, and patients with a creatinine clearance of ≤30mL/min have an average hydroxychlorothiazide renal clearance of 17mL/min.

Following intravenous administration, plasma clearance of valsartan is approximately 2 L/hour and its renal clearance is 0.62 L/hour (about 30% of total clearance).[F4607]

Elimination Route

Elimination from the plasma occurs in a biphasic with a terminal elimination half-life of about 30–50 hours. Steady-state plasma levels of amlodipine are reached after 7-8 days of consecutive daily dosing . Amlodipine is 10% excreted as unchanged drug in the urine. Amlodipine can be initiated at normal doses in patients diagnosed with renal failure , .

Hydrochlorothiazide is eliminated in the urine as unchanged hydrochlorothiazide.

Valsartan, when administered as an oral solution, is primarily recovered in feces (about 83% of dose) and urine (about 13% of dose). The recovery is mainly as unchanged drug, with only about 20% of dose recovered as metabolites.[F4607]

Pregnancy & Breastfeeding use

Pregnancy: Category D. 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. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Potential neonatal adverse effects include skull hypoplasia, anuria, hypotension, renal failure, and death. When pregnancy is detected, discontinue amlodipine, valsartan & hydrochlorothiazide as soon as possible.

Nursing Mothers: It is not known whether amlodipine and valsartan are excreted in human milk, but thiazides are excreted in human milk and valsartan is excreted in rat milk. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.

Contraindication

Do not use in patients with anuria, hypersensitivity to other sulfonamide-derived drugs, or hypersensitivity to any component of this product. Do not coadminister aliskiren with amlodipine, valsartan & hydrochlorothiazide in patients with diabetes

Special Warning

Pediatric Use: The safety and effectiveness of Amlodipine, valsartan & hydrochlorothiazide in pediatric patients have not been established.

Renal Impairment: Safety and effectiveness of Amlodipine, valsartan & hydrochlorothiazide 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.

Hepatic Impairment:

• Amlodipine: Exposure to amlodipine is increased in patients with hepatic insufficiency. The recommended initial dose of amlodipine in patients with hepatic impairment is 2.5 mg, which is not an available strength with Amlodipine, valsartan & hydrochlorothiazide
• Valsartan: No dose adjustment is necessary for patients with mild-to-moderate disease. No dosing recommendations can be provided for patients with severe liver disease.
• Hydrochlorothiazide: Minor alterations of fluid and electrolyte balance may precipitate hepatic coma in patients with impaired hepatic function or progressive liver disease.

Acute Overdose

There is no well documented experience with Amlodipine overdosage. In case of clinically significant hypotension due to Amlodipine over dosage, calls for active cardiovascular support including monitoring of cardiac and respiratory function, elevation of extremities and attention to circulating fluid volume and urine output. Since Amlodipine is highly protein-bound, dialysis is unlikely to be of benefit.

The most common signs and symptoms observed are those caused by electrolyte depletion (hypokalemia, hypochloremia, hyponatremia) and dehydration resulting from excessive diuresis. Rarely, autoimmune hemolytic anemia and other hypersensitivity reactions may complicate the picture.

In the event of over dosage, symptomatic and supportive measures should be employed. Emesis should be induced or gastric lavage performed. Correct dehydration, electrolyte imbalance, hepatic coma and hypotension by established procedures. Hemodialysis can be used successfully to treat severe intoxication.

Limited data are available related to overdosage in humans. The most likely manifestations of overdosage would be hypotension and tachycardia, bradycardia could occur from parasympathetic (vagal) stimulation. If excessive hypotension occurs, the patient should be placed in the supine position and if necessary, has to be given an intravenous infusion of normal saline.

Storage Condition

Store at 20° to 25°C. Keep amlodipine, valsartan & hydrochlorothiazide dry (protect it from moisture).

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