gi drugs

Question 1

metoclopramide ; reglan

Answer 1

Class: Antiemetic

MOA: Blocks dopamine receptors in the CTZ of the CNS; stimulates motility of the upper GI tract

Pharmacokinetics: Onset 1-3 min IV Duration 1-2 hrs

Indications: prevention of nausea and vomiting

AR/SE: drowsiness, extrapyramidal reactions, restlessness, neuroleptic malignant syndrome (potentially fatal syndrome marked by hyperthermia, anxiety, depression, irritability, tardive dyskinesia)

Contraindications: known allergy, possible GI obstructions or hemorrhage; hx of seizures, parkinsons disease.

Dosage: 10 mg IV, IM

Special Considerations: (P Class B)

Question 2

ondansetron ; zofran

Answer 2

Class: Antiemetic

MOA: Blocks the effects of serotonin located in the CTZ of the CNS.

Pharmacokinetics: Onset 15-30 min IV Duration 4-8 hrs

Indications: prevention of nausea and vomiting

AR/SE: headache, constipation, diarrhea, drowsiness,

Contraindications: known allergy

Dosage: 4 mg IV, IM

Special Considerations: (P Class B)

Question 3

promethazine ; phenergan

Answer 3

Class: Antiemetic, antihistamine

MOA: Has inhibitory effect on the CTZ in the brain; blocks the effects of histamine

Pharmacokinetics: Onset 20 min IM, 3-5 min IV;

Duration 4-12 hrs

Indications: treatment and prevention of nausea and vomiting

AR/SE: neuroleptic malignant syndrome, confusion, disorientation, sedation

Contraindications: known allergy, pts with angle-closure glaucoma or pts who are comatose.

Dosage: 12.5-25 mg IV, IM

Special Considerations: (P Class C) Also works to potentiate pain medications such as morphine.