Ondansetron Drug Therapy Protocol

Vocabulary-style flashcards covering the pharmacology, indications, contraindications, and administration protocols for Ondansetron based on the Queensland Ambulance Service Clinical Practice Manual.

Ondansetron Drug Class

Antiemetic 5-HT3 antagonist.

Mechanism of Action

A serotonin 5-HT3 receptor antagonist that works by blocking the action of serotonin, a natural substance that may cause nausea and vomiting.

Indications (4)

Significant nausea AND/OR vomiting.

Absolute Contraindications

Allergy AND/OR Adverse Drug Reaction, Congenital long QT Syndrome, current apomorphine therapy (used in Parkinsons disease), and patients less than $2$ years old.

Relative Contraindication

First trimester pregnancy (may only be administered for extreme and uncontrolled hyperemesis).

Precautions (4)

Hepatic impairment, elderly patients, intestinal obstruction, and patients with risk factors for QT interval prolongation or cardiac arrythmias.

Presentation Types

Ampoule $4\,mg/2\,ml$ and Orally disintegrating tablet (ODT) $4\,mg$.

Onset and Duration

Onset is $5$ mins IV with a duration of several hours.

Routes of Administration (ACP2)

Oral (PO ODT), IM, and IV.

Adult Dosage (PO/IM/IV)

$4$-$8\,mg$. For IV, it must be a slow push over $2$-$3$ minutes. Total maximum dose is $8\,mg$.

Dosing Interval

Must not be given within $8$ hours of previous ondansetron administration.

IV Administration Preference

An IV cannula should not be inserted for the sole purpose of ondansetron administration; ODT ondansetron should always be the preferred option.