Ondansetron

Question 1

Ondansetron - Contraindications (5)

Precautions (4)

Answer 1

Contraindications: PHA Lqt Lk/m

• P: phenylketonuria
• H: hypersensitivity
• A: concurrent apomorphine use (Parkinson’s)
• Lqt: known long QT syndrome (more than 2.5 large squares) as evidence of prolonged ventricular repolarisation
• Lk/m: hypokalemia / hypomagnesaemia

Precautions: L E/d TP
# liver disease (should not receive more than 8mg per day)
# use of diuretics (underlying electrolyte imbalance)
# concurrent use of tramadol (uses same receptor sites)
# pregnancy

Question 2

Ondansetron - Side Effects (12)

Answer 2

Common (5):
> headache
> dizziness
> fever
> constipation 
> rise in liver enzymes

Rare (7):
> hypersensitivity reactions
> QT prolongation
> widened QRS
> tachyarrythmias (AF, SVT)
> seizures
> visual disturbances
> extrapyramidal reactions

Question 3

Ondansetron - Actions

Answer 3

orally dissolving anti-emetic used in:

• general, undifferentiated nausea and vomoting
• prophylaxis in eye trauma and the awake, spinally immobilised patient
• motion sickness in patients

Question 4

Ondansetron - Presentation

Answer 4

4mg orally dissolving tablet

Question 5

Ondansetron - Dose

General, undifferentiated nausea an vomiting

Answer 5

In general, undifferentiated nausea and vomiting:

AD: 4mg ODT orally, repeated @ 5-10/60 once only, max 8mg
PD large child (12-16y): 4mg ODT orally, repeated @ 5-10/60 once only, max 8mg
PD medium child (5-11y): 4mg ODT orally, once only
PD small child (1-4y): 2mg ODT orally, once only

Question 6

Ondansetron - Dose

Prophylaxis in Eye Trauma and Awake, Spinally Immobilised Patients

Answer 6

In prophylactic use for eye trauma and awake, spinally immobilised patients:

AD: 4mg ODT orally, once only
PD large child (12-16y): 4mg ODT orally, once only
PD medium child (5-11y): 4mg ODT orally, once only
PD small child (2-4y): 2mg ODT orally, once only

Question 7

Ondansetron - Dose

Motion sickness

Answer 7

In motion sickness:

AD for patients