Isoprenaline Hydrochloride

Isoprenaline Hydrochloride

[1 amp $4.15]

ADMINISTRATION ROUTES:

  • IV

ALTERNATIVE NAMES:

  • Isuprel

ICU INDICATIONS:

  1. bradycardia

    Note: current international guidelines DO NOT recommend isoprenaline as the first line agent to treat any condition.

PRESENTATION AND ADMINISTRATION:

  • IV:
    200mcg isoprenaline in 1ml and 1mg in 5ml (1:5000) ampoules
    For IV infusion, add 1mg to 50ml of compatible IV fluid and administer at 0-60ml/hr (0-20mcg/min)
    Compatible with the following IV fluids:
    Normal saline, glucose and sodium chloride, 5% glucose, Hartmanns
    Refrigerate. Do not freeze. Protect from light and air. Discard any diluted fluid not used within 24 hours of preparation
    Do not use solution if pinkish to brown in colour or contains precipitate

DOSAGE:

  • IV:
    Usual dosage is 0.5mcg/min to 5mcg/min although doses of 20mcg/min or greater have been used. For bolus dosing, can dilute 200mcg in 20ml and administer 1ml bolus.

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

  • Dose as in normal renal function

DOSAGE IN PAEDIATRICS:

  • IV infusion:
    300mcg/kg in 50ml of compatible IV fluid.
    Commence infusion at 0.1mcg/kg/min (1ml/hr) and titrate to effect.

CLINICAL PHARMACOLOGY:

  • Isoproterenol hydrochloride is a synthetic sympathomimetic amine that is structurally related to epinephrine but acts almost exclusively on beta receptors.

CONTRAINDICATIONS

  1. heart block caused by digitalis intoxication
  2. known hypersensitivity to isoprenaline

WARNINGS

  • Potential for worsening of cardiac function
    Isoprenaline, by increasing myocardial oxygen requirements while decreasing effective coronary perfusion, may have a deleterious effect on the injured or failing heart.
  • Worsening of heart block
    In a few patients, presumably with organic disease of the AV node and its branches, isoprenaline has paradoxically been reported to worsen heart block or to precipitate Adams-Stokes attacks during normal sinus rhythm or transient heart block.
  • Contains sulfite
    Contains sodium metabisulfite, a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people.

PRECAUTIONS

  • General:
    Isoprenaline should generally be started at the lowest recommended dose. This may be gradually increased if necessary while carefully monitoring the patient. Doses sufficient to increase the heart rate to more than 130 beats per minute may increase the likelihood of inducing ventricular arrhythmias. Such increases in heart rate will also tend to increase cardiac work and oxygen requirements which may adversely affect the failing heart or the heart with a significant degree of arteriosclerosis.
    Particular caution is necessary in administering isoprenaline to patients with coronary artery disease, coronary insufficiency, diabetes, hyperthyroidism, and sensitivity to sympathomimetic amines.
  • Laboratory Tests:
    No tests in addition to routine ICU tests are required.
  • Drug/Laboratory Test Interactions
    None noted.

IMPORTANT DRUG INTERACTIONS FOR THE ICU

  • Isoprenaline and adrenalin should not be administered simultaneously because both drugs are direct cardiac stimulants and their combined effects may induce serious arrhythmias. Beta receptor blocking agents and isoprenaline inhibit the effects of each other.

ADVERSE REACTIONS

  • CNS:
    Nervousness, headache, dizziness.
  • Cardiovascular:
    Tachycardia, palpitations, angina, Adams-Stokes attacks, pulmonary edema, hypertension, hypotension, ventricular arrhythmias, tachyarrhythmias.
  • Other:
    Flushing of the skin, sweating, mild tremors, weakness

Critical Care Drug Manual

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