Atenolol with Chlorthalidone

(a ten' oh lole) (klor thal' i done)

PCaution when used during lactation - Caution when used during pregnancy

LCaution when used during lactation - Caution when used during lactation

Molecule Info

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Indication(s) & Dosage

Hypertension  Adult: Per tab contains Atenolol /Chorthalidone: 50/25 or 100/25.  Initially one tab of 50/25 once daily; may increase to one tab of 100/25 once daily according to response.

CrCl

Dosage Recommendation

15-35

Max dose of Atenolol component: 50 mg/day

<15

Max dose of Atenolol component: 50 mg every other day.

Special Populations: In patients with severe renal impairment dose of atenolol is limited to 50mg once a day or on alternate days.

Overdose

Symptoms of Atenolol overdose: Lethargy, bradycardia, respiratory disorder, wheezing, sinus pause, heart block, congestive heart failure, hypotension, bronchospasm.  Symptoms of Chlorthalidone overdose: Nausea, weakness, dizziness, electrolyte imbalance.  Provide supportive and symptomatic treatment; unabsorbed drug may be removed by induced emesis, admin of activated charcoal.  May remove Atenolol from general circulation by haemodialysis.

Contraindications

Sinus bradycardia, 2nd or 3rd degree heart block, cardiogenic shock, anuria, hypersentivity to either product or sulphonamide derivatives.

Special Precautions

Bronchospastic disease, renal or hepatic impairment, elderly.  May aggravate peripheral arterial circulatory disorder.  Beta-blocker can depress myocardial contractility; continued use in patients without history of cardiac failure may in some cases, lead to cardiac failure.  Caution in patients receiving anaesthetic agents that may depress myocardium.  In patients with coronary artery disease, abrupt withdrawal may cause angina pectoris exacerbation, MI.  Atenolol may mask signs of hypoglycaemia and thyrotoxicosis.  Latent DM may manifest with Chlorthalidone therapy.  Chlorthalidone can cause hyperuricaemia and precipitate gout.  Monitor renal functions, potassium levels, and signs of fluid and electrolytes imbalance.  Discontinue if progressive renal impairment is evident.  Not recommended in pregnancy and lactation.  Safety and efficacy in paediatric patients have not been established.

Adverse Drug Reaction(s)

Atenolol: Dyspnoea, wheeziness, bradycardia, hypotension, cold extremities, fatigue, dizziness, insomnia, lethargy, confusion, headache, depression, nightmares, nausea, diarrhoea, constipation, impotence, paraesthesia, rash, Raynaud's phenomenon.  Chlorthalidone: Orthostatic hypotension, GI disturbances, jaundice, pancreatitis, vertigo, lethargy, paraesthesia, photosensitivity, rash, muscle cramps, hypokalaemia, hyponatraemia, hyperglycaemia, hyperuricaemia or gout, leucopenia, agranulocytosis, aplastic anaemia, thrombocytopenia. Potentially Fatal: Atenolol: Heart failure, 2nd or 3rd degree AV block.  Chlorthalidone: Hypersensitivity reaction including toxic epidermal necrolysis.

Drug Interactions

Potentiate effects of other antihypertensives.  Atenolol: Reduced hypotensive effect with pseudoephedrine, xylometazoline or NSAIDs.  Additive effect withcalcium antagonist and catecholamine-depleting drugs e. g.  reserpine.  Increase risk of bradycardia with amisulpride, flecainide, digitalis glycosides.  Increase risk of hypotension with alprostadil, baclofen.  Withdrawal ofclonidine in patients receiving β-blockers may result in rebound hypertension.  Chlorthalidone: May alter insulin and dosage of Oral   hypoglycaemic agents required in diabetics.  May reduce renal clearance of lithium and increases risk of lithium toxicity.  May cause hypokalaemia therefore increase risk of digitalis toxicity.  Risk of hypercalcaemia with paricalcitol.  Increased risk of hypokalaemia with ritodrine, amphotericin B.  Increased responsiveness to tubocurarine. Potentially Fatal: Atenolol: Bradycardia, heart block may occur when used withverapamil or diltiazem.  Severe bradycardia, asystole and heart failure have been reported when used with disopyramide.  High degree of cardiac depression may occur with methoxyflurane.  Chlorthalidone: Risk of cardiac arrhythmias with ketanserin.

Pregnancy Category (FDA) 

Category D: There is positive evidence of human foetal risk, but the benefits from use in pregnant women may be acceptable despite the risk.

Storage

Store at 20-25°C.

Pharmacology

Atenolol is a β-blocker that acts preferentially on the β1 adrenergic receptors in the heart.  Chlorthalidone is a thiazide-like diuretic that reduces BP possibly by inhibiting sodium reabsorption at the beginning of the distal convulated tubule.  Combination of the two drugs results in additive antihypertensive action. Onset: Chlorthalidone: Diuresis occurs within 2 hr. Duration: Chlorthalidone: 48-72 hr.  Absorption: Atenolol: About 50% of an Oral   dose is absorbed from GI tract; Tmax: 2-4 hr after Oral   admin.  Distribution: Atenolol: 6-16% is bound to proteins.  Chlorthalidone: About 75% is bound to plasma protein.  Metabolism: Atenolol: No significant hepatic metabolism.  Excretion: Atenolol: Elimination half-life: 6-7 hr.  Absorbed portion from GI tract is excreted in the urine; remainder is excreted unchanged in faeces.  Chlorthalidone: Mainly excreted unchanged via urine.

ATC Classification

C07AB03 - atenolol; Belongs to the class of selective beta-blocking agents.  Used in the treatment of cardiovascular diseases.

 

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Brand/Product Info


Total Products : 4    
Brand Name Manufacturer/Marketer Composition Dosage Form Pack Size & Price
ATECHLOR 100 Silva Pharmaceuticals Limited Atenolol 50mg+ Chlorthalidone 25mg Tablet 50's: 150.57 MRP
ATECHLOR 50 Silva Pharmaceuticals Limited Atenolol 50mg+ Chlorthalidone 25mg Tablet 50's: 125.47 MRP
CARDIPRO PLUS Square Pharmaceuticals Ltd. Atenolol + Chlorthalidone (50mg + 25mg) Tablet 3x10's: 83.10 MRP
TENOREN Plus ACI Ltd. Atenolol 50mg+ Chlorthalidone 25mg Tablet 50's: 150.50 MRP