amlodipine besylate and valsartan
Brand names: Exforge
Boxed warning
WARNING: FETAL TOXICITY When pregnancy is detected, discontinue Exforge as soon as possible. (5.1) Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus. (5.1) WARNING: FETAL TOXICITY See full prescribing information for complete boxed warning. When pregnancy is detected, discontinue Exforge as soon as possible. ( 5.1 ) Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus. ( 5.1 )
Warnings
5 WARNINGS AND PRECAUTIONS Hypotension: Correct volume depletion prior to initiation ( 5.2 ) Increased angina and/or myocardial infarction ( 5.3 ) Monitor renal function and potassium in susceptible patients ( 5.4 , 5.5 ) 5.1 Fetal Toxicity 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. 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 Exforge as soon as possible [see Use in Specific Populations (8.1)] . 5.2 Hypotension Excessive hypotension was seen in 0.4% of patients with uncomplicated hypertension treated with Exforge in placebo-controlled studies. In patients with an activated renin-angiotensin system, such as volume- and/or salt-depleted patients receiving high doses of diuretics, symptomatic hypotension may occur in patients receiving angiotensin receptor blockers. Volume depletion should be corrected prior to administration of Exforge. Treatment with Exforge should start under close medical supervision. Initiate therapy cautiously in patients with heart failure or recent myocardial infarction and in patients undergoing surgery or dialysis. Patients with heart failure or post-myocardial infarction patients given valsartan commonly have some reduction in blood pressure, but discontinuation of therapy because of continuing symptomatic hypotension usually is not necessary when dosing instructions are followed. In controlled trials in heart failure patients, the incidence of hypotension in valsartan-treated patients was 5.5% compared to 1.8% in placebo-treated patients. In the Valsartan in Acute Myocardial Infarction Trial (VALIANT), hypotension in post-myocardial infarction patients led to permanent discontinuation of therapy in 1.4% of valsartan-treated patients and 0.8% of captopril-treated patients. Since the vasodilation induced by amlodipine is gradual in onset, acute hypotension has rarely been reported after oral administration. Nonetheless, caution, as with any other peripheral vasodilator, should be exercised when administering amlodipine, particularly in patients with severe aortic stenosis. If excessive hypotension occurs with Exforge, place the patient in a supine position and, if necessary, give intravenous normal saline. A transient hypotensive response is not a contraindication to further treatment, which usually can be continued without difficulty once the blood pressure has stabilized. 5.3 Risk of Myocardial Infarction or Increased Angina 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. 5.4 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 Exforge. Monitor renal function periodically in these patients. Consider withholding or discontinuing therapy in patients who develop a clinically significant decrease in renal function on Exforge [see Drug Interactions (7)] . 5.5 Hyperkalemia Drugs that inhibit the renin-angiotensin system can cause hyperkalemia. Monitor serum electrolytes periodically. Some patients with heart failure have developed increases in potassium with valsartan therapy. These effects are usually minor and transient, and they are more likely to occur in patients with pre-existing renal impairment. Dosage reduction and/or discontinuation of Exforge may be required [see Adverse Reactions (6.1)] .
Contraindications
4 CONTRAINDICATIONS Do not use in patients with known hypersensitivity to any component. Do not coadminister aliskiren with Exforge in patients with diabetes [see Drug Interactions (7)] . Known hypersensitivity to any component; Do not coadminister aliskiren with Exforge in patients with diabetes ( 4 )
Overdose
10 OVERDOSAGE Amlodipine 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/m 2 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. Valsartan 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/m 2 basis) (Calculations assume an oral dose of 320 mg/day and a 60 kg patient).
Drug interactions
Uses
Dosage forms & strengths
2 DOSAGE AND ADMINISTRATION General Considerations: Majority of effect attained within 2 weeks ( 2.1 ) May be administered with other antihypertensive agents ( 2.1 ) Hypertension: May be used as add-on therapy for patients not controlled on monotherapy ( 2.2 ) Patients who experience dose-limiting adverse reactions on monotherapy may be switched to Exforge containing a lower dose of that component ( 2.2 ) May be substituted for titrated components ( 2.3 ) When used as initial therapy: Initiate with 5/160 mg, then titrate upwards as necessary to a maximum of 10/320 mg once daily ( 2.4 ) 2.1 General Considerations Dose once daily. The dosage can be increased after 1 to 2 weeks of therapy to a maximum of one 10/320 mg tablet once daily as needed to control blood pressure. The majority of the antihypertensive effect is attained within 2 weeks after initiation of therapy or a change in dose. Exforge may be administered with other antihypertensive agents. 2.2 Add-on Therapy A patient whose blood pressure is not adequately controlled with amlodipine (or another dihydropyridine calcium-channel blocker) alone or with valsartan (or another ARB) alone may be switched to combination therapy with Exforge. A patient who experiences dose-limiting adverse reactions on either component alone may be switched to Exforge containing a lower dose of that component in combination with the other to achieve similar blood pressure reductions. The clinical response to Exforge should be subsequently evaluated and if blood pressure remains uncontrolled after 3 to 4 weeks of therapy, the dose may be titrated up to a maximum of 10/320 mg. 2.3 Replacement Therapy For convenience, patients receiving amlodipine and valsartan from separate tablets may instead wish to receive tablets of Exforge containing the same component doses. 2.4 Initial Therapy A patient may be initiated on Exforge if it is unlikely that control of blood pressure would be achieved with a single agent. The usual starting dose is Exforge 5/160 mg once daily in patients who are not volume-depleted.