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Beta-1 Selective Adrenoceptor Blocker (Cardioselective Beta-Blocker) Pregnancy: Caution should be exercised during pregnancy. Crosses the placental barrier; possibility of foetal injury cannot be excluded (no first-trimester studies); associated with intra-uterine growth retardation. Anticipated benefit must be weighed against possible risks, particularly in first and second trimesters. Breast-feeding: significant accumulation in breast milk; neonates may be at risk of hypoglycaemia and bradycardia.

Atenolol

Brand names: Tenormin

Atenolol is a relatively cardioselective beta-blocker used for hypertension, angina and certain arrhythmias, and after myocardial infarction.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Hypertension: 100 mg once daily orally (some patients respond to 50 mg once daily). Angina: 100 mg once daily orally or 50 mg twice daily.
Route: Oral (also intravenous for cardiac arrhythmias and myocardial infarction)
Frequency: Once daily (angina alternatively twice daily)
The dose must always be adjusted to individual requirements, with the lowest possible starting dose. HYPERTENSION: most patients respond to 100 mg once daily; some respond to 50 mg once daily; effect fully established after one to two weeks. ANGINA: 100 mg once daily or 50 mg twice daily (unlikely to gain additional benefit from higher doses). CARDIAC ARRHYTHMIAS: initial dose 2.5 mg IV over 2.5 minutes (1 mg/minute), repeated at 5-minute intervals until response up to a maximum of 10 mg; or by infusion 0.15 mg/kg over 20 minutes; oral maintenance 50-100 mg daily as a single dose. MYOCARDIAL INFARCTION (within 12 hours of chest pain onset): atenolol 5-10 mg by slow IV injection (1 mg/minute), then 50 mg orally ~15 minutes later, a further 50 mg orally 12 hours after the IV dose, then 100 mg orally once daily. Elderly: dosage requirements may be reduced, especially with impaired renal function.

Dose adjustments

Renal

Dosage should be adjusted in severe renal impairment. CrCl 15-35 mL/min/1.73m2: oral 50 mg daily (IV 10 mg every two days). CrCl <15 mL/min/1.73m2: oral 25 mg daily or 50 mg on alternate days (IV 10 mg every four days). Haemodialysis: 50 mg orally after each dialysis under hospital supervision.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients
  • Cardiogenic shock
  • Uncontrolled heart failure
  • Sick sinus syndrome
  • Second- or third-degree heart block
  • Untreated phaeochromocytoma
  • Metabolic acidosis
  • Bradycardia (<45 bpm)
  • Hypotension
  • Severe peripheral arterial circulatory disturbances

Side effects

  • Bradycardia (common)
  • Cold extremities (common)
  • Gastrointestinal disturbances (common); fatigue (common)
  • Postural hypotension which may be associated with syncope (rare); Raynaud's phenomenon (rare)
  • Sleep disturbances (uncommon); dizziness, headache, paraesthesia (rare); bronchospasm in patients with asthma or history of asthmatic complaints (rare)

Interactions

  • Should not be withdrawn abruptly (withdraw gradually over 7-14 days)
  • Caution in patients with first-degree heart block (negative effect on conduction time)
  • May mask symptoms of hypoglycaemia (particularly tachycardia) and signs of thyrotoxicosis
  • May cause a more severe reaction to allergens; such patients may be unresponsive to usual doses of adrenaline (epinephrine)
  • Avoid in reversible obstructive airways disease unless compelling clinical reasons (use with caution)

Clinical monograph

How it works

It selectively blocks beta-1 adrenoceptors in the heart, reducing heart rate, myocardial contractility and conduction velocity, thereby lowering cardiac workload and blood pressure.

Prescribing in practice

  • Do not stop abruptly, as sudden withdrawal can precipitate rebound angina, arrhythmia or myocardial infarction, so taper when discontinuing.
  • It is renally excreted and accumulates in renal impairment, so dose reduction is needed as function declines.
  • Use caution in asthma, peripheral arterial disease and with other rate-limiting drugs, and be aware it may mask signs of hypoglycaemia in diabetes.

Monitoring

Monitor heart rate and blood pressure, and assess renal function as it influences dosing and accumulation.

Counselling the patient

  • Do not stop the medicine suddenly without medical advice.
  • Report marked dizziness, breathlessness, wheeze or a very slow pulse.
  • Be aware it may blunt the usual warning symptoms of low blood sugar if you have diabetes.

Evidence & guidelines

Beta-blockade after myocardial infarction reduces mortality, and NICE positions atenolol within the management of hypertension, angina and arrhythmia.

Reference: NICE NG133 (Hypertension in adults, 2019 updated 2023); NICE NG185 (ACS, 2020); ESC/ESH Hypertension Guidelines (2023); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

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