Antiemetics

Question 1

• Inhibits histamine receptors
  e. g. Cyclizine, Cinnarzine, Promethazine
• Drowsiness and sedation

Answer 1

Histamine receptor antagonist

Question 2

• Histamine receptor antagonist

- Treats motion sickness

Answer 2

Cyclizine

Question 3

• Histamine receptor antagonist

- Treats motion sickness and vestibular disorders

Answer 3

Cinnarizine

Question 4

• Histamine receptor antagonist

- Treats severe morning sickness

Answer 4

Promethazine

Question 5

• Activates H- receptors on blood vessels of inner ear

- GI disturbances, headache, rashes

Answer 5

H3 Agonists

Question 6

e. g. Hyoscine, Scopolamine
- Non-selective antagonist
- Inhibits Muscarinic receptor
- Motion sickness
- Dry mouth, blurred vision
- Oral or transdermal patch

Answer 6

Muscarinic receptor antagonist

Question 7

Phenothaizines, metoclopramide, domperidone are example of…

Answer 7

Dopamine receptor antagonists

Question 8

• Strong in the chemoreceptor trigger zone

- Have powerful antiemetic action

Answer 8

Dopamine receptor antagonists

Question 9

• Dopamine receptor antagonist
• Morning sickness
• Sedative, hypotension, dystonia, dystinesia

Answer 9

Phenothiazines

Question 10

• Dopamine receptor antagonist
• Penetrated blood/brain barrier
• Acts on GI affecting mobility
• Movement disorders, fatigue, spasmodic, restlessness, menstruation disorders

Answer 10

Metolopramide

Question 11

• Dopamine receptor antagonist
• Used for migrane and cytotoxic therapy
• Orally administered
• Dry mouth, abdominal crampd, diarrhoea, nausea, rash, itching

Answer 11

Domperidone

Question 12

e. g. Ondasteron
- Drug of choice for chemo and anesthetics
- Given orally, IV or IM
- GI disturbances, headache

Answer 12

Serotonin receptor antagonists

Question 13

e. g. Nabilone
- Acts as an antagonist of the CB receptors but mechanism as an antiemetic is unknown
- CB1 is found in brainstem
- Drowsiness, dizziness, dry mouth, mood changes, hypertension, hallucinations

Answer 13

Cannabinoids

Question 14

e. g. Dexamethasone
- Treats vomiting caused by chemo
- Mechanism not fully understood
- Used in combination with D2 (dopamine) and SHT3 (serotonin) antagonists
- Insomnia, mood changes, slow healing, sweating, headache, dizziness, nausea, muscle weakness

Answer 14

Corticosetroids

Question 15

• Active in late phase emesis with cytotoxic drugs
• Aprepitant= substance P antagonist used for chemo and anesthetics
• IV and Oral admin
• Fatigue, constipation, loss of appetite, dizziness, diarrhea, anorexia, headache

Answer 15

Neurokinin-1 antagonist