PHARM EXAM 4: N/V

what five neurotransmitters receptors are involved in vomiting

1. Muscarinic (M1) receptors

2. Dopamine (D2) receptors

3. Histamine (H1) receptors

4. 5-hydroxytryptamine3 (5-HT3) receptors

5. Substance P/neurokinin 1 (NK1) receptors

Phenothiazines drugs

Promethazine (Phenergan)*, Chlorpromazine, Perphenazine, Prochlorperazine (Compazine)

Phenothiazines: MOA

antagonize D2-dopamine receptors in the brain, therefore decreasing dopamine

Phenothiazines use

prevention and treatment of nausea and vomiting associated with

• Surgery

• Anesthesia

• Migraines

• Chemo

• Motion sickness

Phenothiazines AE

Anticholinergic effects such as dry mouth, blurred vision, urinary retention, constipation, acute confusion, dizziness, tachycardia, respiratory depression (especially under 2 yearsof age)

Antihistamines drugs

Hydroxyzine*, diphenhydramine, dimenhydrinate, doxylamine succinate, meclizine

Antihistamines moa

blocks the H1 receptor, therefore blocking the action of acetylcholine in the brain.

Antihistamines use

treating nausea and vomiting and preventing and treating motion sickness, also during anesthesia

Antihistamines adverse effects

anticholinergic effects such as drowsiness, dizziness, confusion, dry mouth, thickened respiratory secretions, blurred vision, urinary retention, tachycardia

antihistamine spotlight drug

diclegis

diclegis

Combination of doxylamine succinate (antihistamine) and pyridoxine (Vit B6)

what makes diclegis unique

approved to be used during pregnancy, one of the few drugs approved for use during pregnancy for N/V

5-Hydroxytryptamine3 (5-HT3) drug

ondansetron*, dolasetron, granisetron, palonosetron

5-Hydroxytryptamine3 (5-HT3) moa

antagonize serotonin receptors

5-Hydroxytryptamine3 (5-HT3) use

prevent or treat moderate to severe nausea and vomiting associate with

• Chemotherapy

• Radiation therapy

• Postoperative status

5-Hydroxytryptamine3 (5-HT3) adverse effect

QT prolongation, diarrhea, constipation, headache

Substance P/Neurokinin 1 Antagonists drugs

aprepitant*, netupitant/palonosetron, rolapitant

Substance P/Neurokinin 1 Antagonists moa

blocks the activity of substance P at NK1 receptors in the brain

Substance P/Neurokinin 1 Antagonists use

o Often used in combination with 5-HT3 receptors or glucocorticoids for patients receiving highly emetic chemotherapy

o Prevention of post-op N/V

Substance P/Neurokinin 1 Antagonists adverse effects

fatigue, weakness, abnormal heart rhythm, headache, hiccups

nonpharmacologic management

acupuncture, acupressure, ginger

N/V considerations

•Identify the circumstances that cause nausea/vomiting

•Drugs should be taken prior to nausea/vomiting occurring for best effects

•Certain antiemetics may cause drowsiness, safety precautions must be taken

•Use lowest effective dose to prevent unwanted side effects