Propranolol

Propranolol

[1 tablet 5 cents]

ADMINISTRATION ROUTES:

• PO

ALTERNATIVE NAMES:

• Cardinol

ICU INDICATIONS:

1. thyrotoxiccrisis
2. use as a centrally acting ‘beta blocker’

PRESENTATION AND ADMINISTRATION:

• PO Tablets:
  Cardinol 10mg tablets (red) and 40mg (red)
• Long Acting Capsules:
  Cardinol 160mg long acting capsules

DOSAGE:

• PO:
  Usual dosage for thyrotoxicosis, 10mg- 40mg 3-4 times a day; usual maximum dosage 320mg daily in divided doses

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

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

DOSAGE IN PAEDIATRICS:

• PO:
  0.2-0.5mg/kg 6-12 hourly oral; slowly increase to 1.5mg/kg 6-12 hrly if required

CLINICAL PHARMACOLOGY:

• Propranolol hydrochloride is a synthetic non-selective beta-adrenergic receptor blocking agent. It is the first line agent for thyrotoxicosis because it reduces peripheral conversion of T4 to T3.

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:
  Beta blockers 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