TENORETIC- atenolol and chlorthalidone tablet
AstraZeneca Pharmaceuticals LP
DESCRIPTION
TENORETIC? (atenolol and chlorthalidone) is for the treatment of hypertension. It combines the antihypertensive activity of two agents: beta1 -selective (cardioselective) hydrophilic blocking agent (atenolol, TENORMIN?) and monosulfonamyl diuretic (chlorthalidone). Atenolol is Benzeneacetamide, 4-[2'-hydroxy-3'-[(1-methylethyl) amino] propoxy]-.
Atenolol (free base) is relatively polar hydrophilic compound with water solubility of 26.5 mg/mL at 37? C. It is freely soluble in 1N HCl (300 mg/mL at 25?C) and less soluble in chloroform g/mL at 25?C).
Chlorthalidone is 2-Chloro-5-(1-hydroxy-3-oxo-1-isoindolinyl) benzene sulfonamide:
Chlorthalidone has water solubility of 12 mg/100 mL at 20?C.
Each TENORETIC 100 Tablet contains:
Atenolol (TENORMIN?)?????????????100 mg
Chlorthalidone??????????????????.. 25 mg
Each TENORETIC 50 Tablet contains:
Atenolol (TENORMIN?)?????????????..50 mg
Chlorthalidone???????????????????.25 mg
Inactive ingredients: magnesium stearate, microcrystalline cellulose, povidone, sodium starch glycolate.
CLINICAL PHARMACOLOGY
Tenoretic
Atenolol and chlorthalidone have been used singly and concomitantly for the treatment of hypertension. The antihypertensive effects of these agents are additive, and studies have shown that there is no interference with bioavailability when these agents are given together in the single combination tablet. Therefore, this combination provides convenient formulation for the concomitant administration of these two entities. In patients with more severe hypertension, TENORETIC may be administered with other antihypertensives such as vasodilators.
Atenolol
Atenolol is beta1 -selective (cardioselective) beta-adrenergic receptor blocking agent without membrane stabilizing or intrinsic sympathomimetic (partial agonist) activities. This preferential effect is not absolute, however, and at higher doses, atenolol inhibits beta2 -adrenoreceptors, chiefly located in the bronchial and vascular musculature.
INDICATIONS AND USAGE SECTION
TENORETIC is indicated for the treatment of hypertension, to lower blood pressure. Lowering blood pressure lowers the risk of fatal and non-fatal cardiovascular events, primarily strokes and myocardial infarctions. These benefits have been seen in controlled trials of antihypertensive drugs from wide variety of pharmacologic classes including atenolol and chlorthalidone.
CONTRAINDICATIONS
TENORETIC is contraindicated in patients with: sinus bradycardia; heart block greater than first degree; cardiogenic shock; overt cardiac failure anuria; hypersensitivity to this product or to sulfonamide-derived drugs.
WARNINGS
Cardiac Failure
Sympathetic stimulation is necessary in supporting circulatory function in congestive heart failure, and beta blockade carries the potential hazard of further depressing myocardial contractility and precipitating more severe failure.
Renal and Hepatic Disease and Electrolyte Disturbances
Since atenolol is excreted via the kidneys, TENORETIC should be used with caution in patients with impaired renal function.
Ischemic Heart Disease
Following abrupt cessation of therapy with certain beta-blocking agents in patients with coronary artery disease, exacerbations of angina pectoris and, in some cases, myocardial infarction have been reported.
Concomitant Use of Calcium Channel Blockers
Bradycardia and heart block can occur and the left ventricular end diastolic pressure can rise when beta-blockers are administered with verapamil or diltiazem
Bronchospastic Diseases
PATIENTS WITH BRONCHOSPASTIC DISEASE SHOULD, IN GENERAL, NOT RECEIVE BETA BLOCKERS
Major Surgery
Chronically administered beta-blocking therapy should not be routinely withdrawn prior to major surgery, however the impaired ability of the heart to respond to reflex adrenergic stimuli may augment the risks of general anesthesia and surgical procedures.
PREGNANCY AND FETAL INJURY
Atenolol can cause fetal harm when administered to pregnant woman. Atenolol crosses the placental barrier and appears in cord blood
Dosage and Administration
DOSAGE MUST BE INDIVIDUALIZED
Chlorthalidone is usually given at dose of 25 mg daily; the usual initial dose of atenolol is 50 mg daily. Therefore, the initial dose should be one TENORETIC 50 tablet given once day. If an optimal response is not achieved, the dosage should be increased to one TENORETIC 100 tablet given once day.
When necessary, another antihypertensive agent may be added gradually beginning with 50 percent of the usual recommended starting dose to avoid an excessive fall in blood pressure.
HOW SUPPLIED
TENORETIC 50 Tablets (atenolol 50 mg and chlorthalidone 25 mg), NDC 0310-0115, (white, round, biconvex, uncoated tablets with TENORETIC on one side and 115 on the other side, bisected) are supplied in bottles of 100 tablets.
TENORETIC 100 Tablets (atenolol 100 mg and chlorthalidone 25 mg), NDC 0310-0117, (white, round, biconvex, uncoated tablets with TENORETIC on one side and 117 on the other side) are supplied in bottles of 100 tablets.
Storage:
Store at controlled room temperature, 20-25?C (68-77?F) [see USP]. Dispense in well-closed, light-resistant containers.
TENORETIC is trademark of the AstraZeneca group of companies.
