Atenolol + Chlorthalidone

Atenolol + Chlorthalidone is a combination of two medicines used to treat hypertension when a single medication is not effective. It helps reduce the risk of future heart attack and stroke.

Atenolol is a beta1-selective beta-blocker that reduces heart rate and cardiac output, lowering blood pressure and myocardial oxygen demand. Chlorthalidone is a thiazide-like diuretic that increases sodium and chloride excretion at the distal convoluted tubule, removing excess water and salts from the body.

The initial dose is Atenolol 50 mg + Chlorthalidone 25 mg once daily. Common side effects include nausea, headache, fatigue, dizziness, cold extremities, and electrolyte imbalances.

• Hypertension (high blood pressure) - to lower blood pressure and reduce cardiovascular event risk

Atenolol is a beta1-selective (cardioselective) beta-adrenergic receptor blocking agent that provides reduction in resting and exercise heart rates and cardiac output, reduction of systolic and diastolic blood pressure, and reduction in reflex orthostatic tachycardia.

Chlorthalidone is a monosulfonamyl diuretic with prolonged action and low toxicity. It produces diuresis with greatly increased excretion of sodium and chloride at the distal convoluted tubule of the nephron.

Combination of the two drugs results in additive antihypertensive action.

Atenolol blocks beta1 receptors in the heart, reducing heart rate and contractility, which decreases blood pressure and myocardial oxygen demand. Chlorthalidone inhibits sodium reabsorption at the distal convoluted tubule, increasing excretion of water and electrolytes to lower blood pressure. Together, they provide effective blood pressure control.

Initial Dose: Atenolol 50 mg + Chlorthalidone 25 mg once daily.

Dose Adjustment: Additional antihypertensive agents may be added gradually (starting at 50% of usual dose) if optimal response is not achieved.

Renal Dose: Dose adjustment needed in severe renal impairment (atenolol is renally excreted).

Elderly: Insufficient data for patients ≥65 years; use with caution.

Take this medicine in the dose and duration as advised by your doctor. Swallow the tablet whole - do not chew, crush or break. May be taken with or without food, but take at a fixed time (morning is preferred to avoid nighttime urination).

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not double the dose. Do not stop suddenly.

• Nausea
• Diarrhea
• Headache
• Fatigue
• Dizziness
• Cold extremities
• Bradycardia
• Postural hypotension
• Increased blood uric acid
• Hypokalemia
• Hyponatremia
• Hypomagnesemia
• Hypercalcemia
• Glucose intolerance
• Increased blood lipids
• Anorexia
• Gastric irritation
• Vomiting
• Constipation
• Dyspnea

Serious Precautions:

• Do not stop suddenly - may cause rebound hypertension, increasing risk of heart attack and stroke
• Caution in diabetic patients - beta-blockers may mask hypoglycemia symptoms; chlorthalidone may cause glucose intolerance
• May aggravate peripheral arterial circulatory disorders
• Gout risk - chlorthalidone may cause hyperuricemia
• Dehydration risk - drink plenty of fluids; report extreme thirst, muscle weakness, or dry mouth
• Monitor serum electrolytes regularly - risk of electrolyte imbalance
• Monitor renal function - discontinue if progressive renal impairment develops
• Pregnancy Category D - risk to fetus in third trimester
• Caution during breastfeeding - excreted in breast milk

• Sinus bradycardia
• 2nd or 3rd degree heart block
• Cardiogenic shock
• Anuria
• Hypersensitivity to atenolol, chlorthalidone, or sulfonamide derivatives
• Overt cardiac failure

• Other antihypertensive agents: Additive effects
• Catecholamine-depleting drugs (reserpine): Hypotension and marked bradycardia
• Calcium channel blockers, Amiodarone: Additive effects
• Prostaglandin synthase inhibitors (indomethacin): May decrease hypotensive effects of beta-blockers
• Digitalis glycosides: Additive bradycardia and AV conduction slowing

[UNSAFE] Alcohol with Atenolol + Chlorthalidone may cause excessive drowsiness. Avoid alcohol.

[CONSULT YOUR DOCTOR] Atenolol + Chlorthalidone is unsafe during pregnancy (Category D). There is definite evidence of risk to the developing baby. Use only if potential benefit justifies the risk.

[CONSULT YOUR DOCTOR] Atenolol + Chlorthalidone is excreted in breast milk and may harm the baby. Use with caution during breastfeeding.

Safety and efficacy in pediatric patients have not been established.

Insufficient clinical data for patients aged 65 and older; use with caution.

[CAUTION] Use with caution in kidney disease. Dose adjustment needed in severe renal impairment (atenolol is renally excreted).

[CAUTION] Use with caution in liver disease. Not recommended in severe liver disease.

No specific information on overdose in humans. Treatment: symptomatic and supportive, removal of unabsorbed drug (induced emesis or activated charcoal). Atenolol can be removed by hemodialysis. Manage dehydration, electrolyte imbalance, and hypotension.

Store in a cool and dry place, protected from light.

Atenolol (C₁₄H₂₂N₂O₃) + Chlorthalidone (C₁₄H₁₁ClN₂O₄S)