Ondansetron

Ondansetron

[$1.72; 4mg ampoules $3.17]

ADMINISTRATION ROUTES:

  • PO, IV, IM

ALTERNATIVE NAMES:

  • Zofran

ICU INDICATIONS:

  1. nausea and vomiting

PRESENTATION AND ADMINISTRATION:

  • IV:
    Ondansetron 4mg/2ml and 8mg/4ml
    Doses of up to 8mg can be administered undiluted by slow IV injection over 2 to 5 minutes
    Doses of 8mg to 32mg, which are rarely if every administered in ICU, should be diluted in 50-100ml of compatible IV fluid and infused over 15 minutes or more.
    Compatible with the following IV fluids:
    Normal saline, 5% dextrose, Glucose and sodium chloride, Hartmanns, 10% mannitol
    Store at room temperature. Protect from light
  • IM:
    Inject undiluted into a large muscle (this route is not routinely used in ICU)
  • PO:
    Tablets:

    Zofran 4mg and 8 mg tablets (yellow)
    Dispersible tablets:
    Zofran zydis 4mg and 8mg tablets (white)

DOSAGE:

  • IV:
    4-8mg 6 hourly
  • PO:
    4-8mg 6 hourly

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

  • Dose as in normal renal function

DOSAGE IN PAEDIATRICS:

  • 0.2mg/kg 6-12 hourly

CLINICAL PHARMACOLOGY:

  • Ondansetron is a selective 5-HT3 receptor antagonist. While ondansetron’s mechanism of action has not been fully characterized, it is not a dopamine-receptor antagonist.
  • Serotonin receptors of the 5-HT3 type are present both peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone of the area postrema. It is not certain whether ondansetron’s antiemetic action in chemotherapy-induced nausea and vomiting is mediated centrally, peripherally, or in both sites.

CONTRAINDICATIONS:

  1. hypersensitivity to ondansetron

WARNINGS

  • Nil

PRECAUTIONS

  • General: Nil
  • Laboratory Tests: No tests additional to routine ICU tests are indicated
  • Drug/Laboratory Test Interactions: None reported

IMPORTANT DRUG INTERACTIONS FOR THE ICU

  • None of note

ADVERSE REACTIONS

  • Body as a Whole:
    Rash, anaphylaxis
  • Cardiovascular:
    Hypotension, tachycardia, flushing
  • Gastrointestinal:
    Constipation, elevated transaminases
  • Neurological:
    Headache

Critical Care Drug Manual

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