Antiemetics

Question 1

Metoproclamide (Reglan) drug class

Answer 1

Dopamine receptor antagonist & serotonin (5H3T) receptor agonist

Question 2

Metoproclamide MOA

Answer 2

Blocks D2 receptors in the CRTZ preventing N/V

GI prokinetic effect via serotonin receptor agonism (some increased postsynaptic Ach at muscarinic receptors)

Question 3

Metoproclamide kinetics

Answer 3

30-40% PB, 1-3 minute onset IV, Vd 2-4L/kg, DOA 1-2 hours

Hepatic metab., excreted in urine (40% unchanged). E1/2t 2-4 hrs

Question 4

Metoproclamide SE

Answer 4

Increased gastric motility, LES tone (useful pre-RSI)

Extrapyramidal effects (motor restlessness, tardive dyskinesia)

Abd. cramping, sedation, increased prolactin, dry mouth

Question 5

Metoproclamide CI/Cautions

Answer 5

Parkinsons (especially with Levodopa)

Bowel obstruction, GI bleed

Seizures

Arrhythmias previously on Zofran

Question 6

Metoproclamide dosing

Answer 6

10-20mg IV over 3-5 minutes (give 15 minutes prior to RSI if used for prophylaxis)

Question 7

Ondansetron (Zofran) drug class

Answer 7

Serotonin (5HT3) antagonist

Question 8

Ondansetron MOA

Answer 8

Blocks serotonin receptors in the CRTZ and peripherally

Question 9

Ondansetron kinetics

Answer 9

30 minute IV onset, DOA 4-8hrs

Liver metab., with renal excretion (5%) unchanged. E1/2t 3-4hrs.

Question 10

Ondansetron SE

Answer 10

HA (with rapid admin), sedation, arrhythmias, constipation, diarrhea, fatigue

Question 11

Ondansetron CI/Cautions

Answer 11

Hypersen.

Liver disease

SSRI’s

MAOIs

Question 12

Ondansetron dosing

Answer 12

4-8mg IV over 2-5 minutes