Atenolol

Atenolol

[tablets 1 cent each]

ADMINISTRATION ROUTES:

  • PO, NG

ALTERNATIVE NAMES:

  • Noten

ICU INDICATIONS:

  1. hypertension
  2. acute myocardial infarction
  3. secondary prevention in patients with coronary artery disease
  4. angina
  5. rate control

PRESENTATION AND ADMINISTRATION:

  • PO/ NG:
    Pacific atenolol: orange 50mg and 100mg tablets.
    Tablets may be crushed and administered via nasogastric tube.

DOSAGE:

  • PO:
    Commence at 50mg daily; increase to 100mg daily as tolerated.
    Note: generally metoprolol is used as the 1st line beta blocker rather than atenolol in our ICU

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

  • Dose in renal impairment [GFR (ml/min)]
    <10: 50mg once daily
    10-20: dose as in normal renal function
    >20-50: dose as in normal renal function
  • Dose in renal replacement therapy
    CAPD: 50mg once daily
    HD: 50mg once daily
    CVVHDF: dose as in normal renal function

DOSAGE IN PAEDIATRICS:

  • Safety and effectiveness in paediatric patients have not been established 1-2mg/kg PO 12-24hrly.

CLINICAL PHARMACOLOGY:

  • Atenolol is a beta1-selective (cardioselective) beta-adrenergic receptor blocking agent without membrane stabilizing or intrinsic sympathomimetic (partial agonist) activities. This preferential effect is not absolute, however, and at higher doses, atenolol inhibits beta2-adrenoreceptors, chiefly located in the bronchial and vascular musculature. Absorption of an oral dose of atenolol is rapid and consistent but incomplete. Approximately 50% of an oral dose is absorbed from the gastrointestinal tract, the remainder being excreted unchanged in the faeces. Peak blood levels are reached between 2 and 4 hours after ingestion.

CONTRAINDICATIONS:

  1. sinus bradycardia
  2. heart block greater than first degree
  3. cardiogenic shock
  4. overt cardiac failure
  5. asthma

WARNINGS

  • Cardiac Failure:
    Sympathetic stimulation is necessary in supporting circulatory function in congestive heart failure, and beta blockade carries the potential hazard of further depressing myocardial contractility and precipitating more severe failure.
  • Discontinuation of therapy:
    Discontinuation of therapy in a patient with coronary artery disease may lead to rebound angina, arrhythmia or myocardial infarction.
  • Diabetes and Hypoglycemia:
    Beta blockers may mask tachycardia occurring with hypoglycaemia.
  • Thyrotoxicosis:
    Beta-adrenergic blockade may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism. Abrupt withdrawal of beta blockade might precipitate a thyroid storm.

PRECAUTIONS

  • General:
    Atenolol may aggravate peripheral arterial circulatory disorders.
  • Laboratory Tests:
    No tests in addition to routine ICU tests are required
  • Drug/Laboratory Test Interactions :
    None known

IMPORTANT DRUG INTERACTIONS FOR THE ICU

  • Beta blockers may exacerbate the rebound hypertension which can follow the withdrawal of clonidine

ADVERSE REACTIONS

  • Body as a Whole:
    Tiredness, Fatigue
  • Cardiovascular System:
    Bradycardia , Cold extremities, Hypotension, Leg pain
  • Respiratory System:
    Wheeziness, Dyspnoea
  • Digestive System:
    Diarrhoea, Nausea
  • Nervous System:
    Dizziness, Vertigo, Light-headedness

Critical Care Drug Manual

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