Ondansetron

Question 1

What is the presentation of Ondansetron?

Answer 1

4mg ODT

8mg in 4mL glass amp.

Question 2

What is the pharmacology and action of Ondansetron?

Answer 2

Antiemetic.
Action:
5HT3 antagonist which blocks receptors centrally and peripherally.

Question 3

List the PEI’s for Ondansetron.

Answer 3

1. Undifferentiated nausea and vomiting.
2. Prophylaxis for spinally immobilised or eye injured pts
3. Vestibular nausea in pts aged <21

Question 4

List the contraindications for Ondansetron.

Answer 4

1. Known hypersensitivity
2. Concurrent apomorphine use
3. Known long QT syndrome
4. Hypokalaemia or hypomagnesaemia

Question 5

List the precautions for Ondansetron.

Answer 5

1. Pts with liver disease should not exceed 8mg a day
2. Pts on diuretics may have underlying electrolyte imbalances
3. Contains aspartame; not for phenylketonurics
4. Concurrent use with Tramadol
5. Pregnancy

Question 6

List the common and rare side effects of Ondansetron.

Answer 6

Common:

1. Constipation
2. Headache
3. Fever
4. Dizziness
5. Rise in liver enzymes

Rare:

1. Hypersensitivity rxns (inc. anaphylaxis)
2. QT prolongation
3. Widened QRS complex
4. Tachyarrhythmias (inc. AF and SVT)
5. Seizures
6. Extrapyramidal rxns
7. Visual disturbances (inc. transient loss of vision)

Question 7

What is the onset, peak and duration of ODT Ondansetron?

Answer 7

O: 2mins
P: 20mins
D: 120mins

Question 8

What is the onset, peak and duration of IV Ondansetron?

Answer 8

O: 5mins
P: 10mins
D: 2.5 - 6.1hrs

Question 9

What note is made about the administration of IV Ondansetron?

Answer 9

Should be done as a slow push over a minimum of 30s.