atenolol + chlortalidone: clinical use

Prescribing considerations

• Assess whether both components and the available fixed proportion are appropriate.
• Avoid abrupt withdrawal in ischaemic heart disease.
• Use caution with controlled heart failure, poor cardiac reserve, first-degree heart block, peripheral arterial disease, Prinzmetal angina, diabetes, gout risk, hepatic impairment and previous severe allergy.
• A history of asthma or wheezing is highlighted because beta-1 selectivity is not absolute.
• Efficacy is reduced in renal insufficiency; severe renal failure is contraindicated.
• Chlortalidone-related ocular reactions can develop within hours to weeks and require urgent assessment.

Contraindications and cautions

• Hypersensitivity to atenolol, chlortalidone, sulfonamide-derived medicines or an excipient
• Bradycardia, hypotension or cardiogenic shock
• Second- or third-degree heart block or sick sinus syndrome
• Uncontrolled heart failure
• Severe peripheral arterial circulatory disturbance
• Severe renal failure
• Metabolic acidosis
• Untreated phaeochromocytoma
• Pregnancy or breastfeeding

Monitoring

• Blood pressure and pulse
• Renal function and fluid status
• Sodium and potassium
• Blood glucose in diabetes or impaired glucose tolerance
• Uric acid where gout or persistent hyperuricaemia is relevant
• Symptoms of heart failure, bronchospasm, postural hypotension and peripheral hypoperfusion

Clinical pharmacology

Atenolol is a hydrophilic, beta-1-selective antagonist with negative chronotropic and inotropic effects and predominantly renal elimination. Chlortalidone promotes sodium and chloride excretion, with some potassium loss, and has a substantially longer elimination half-life. Coadministration has little effect on the pharmacokinetics of either component.

Formulation and product differences

• The selected product is an oral, film-coated tablet.
• It contains less than 1 mmol sodium per tablet and is essentially sodium-free.
• Appearance and excipients may differ between manufacturers; check the relevant pack leaflet.

Tablet

Route: Oral

Strengths: 50 mg + 12.5 mg, 100 mg + 25 mg