Calock Tablet

Combination of a calcium-channel blocker and a beta-blocker for:

• High blood pressure not controlled by one medicine
• Stable angina (chest pain)

Adults: one tablet (amlodipine 5 mg + atenolol 50 mg) once daily; maximum amlodipine 10 mg + atenolol 100 mg once daily (the 5/25 strength is used in the elderly or when a lower dose is enough).

• Take at the same time each day.
• Kidney impairment: atenolol dose may need reducing.
• Do not stop suddenly — angina or heart attack risk; taper over 1–2 weeks.

• Slow heart rate (below 50/min), heart block (2nd/3rd degree), sick sinus syndrome
• Cardiogenic shock, uncompensated heart failure
• Severe low blood pressure, severe aortic stenosis
• Severe peripheral circulation problems
• Untreated phaeochromocytoma
• Metabolic acidosis
• Allergy to dihydropyridines or atenolol

Common: ankle swelling, flushing, headache, tiredness, cold hands and feet, slow heartbeat, dizziness, stomach upset.

Less common: sleep problems, vivid dreams, low mood, erectile difficulty, palpitations, gum overgrowth.

Rare but serious: heart block, worsening heart failure, bronchospasm in asthmatics, masking of low blood sugar signs.

• Asthma or COPD: caution (atenolol may narrow airways).
• Diabetes: may hide symptoms of low blood sugar (except sweating).
• Psoriasis may worsen.
• Monitor pulse; report if it falls below 50/min.

Not recommended in pregnancy (atenolol linked to low birth weight); doctor may choose alternatives. Avoid while breastfeeding (atenolol accumulates in milk).

• Verapamil, diltiazem (heart block, very slow pulse) — avoid
• Clonidine (dangerous rebound if clonidine stopped first)
• Insulin and diabetes tablets (hidden hypoglycaemia)
• NSAIDs (reduced effect)
• Simvastatin (limit dose with amlodipine); grapefruit, clarithromycin, itraconazole (raise amlodipine)
• Digoxin, amiodarone (slow pulse)

Very low blood pressure, slow heartbeat, heart failure, breathing difficulty. Emergency treatment.

Store below 30°C, protected from light.