IBS

Question 1

Antispasmodic agents are classified into
Often used for the treatment of IBS

Answer 1

Antimuscarinics
Direct smooth muscle relaxants
Ca 2+ channel blockers

Question 1

Antimuscarinics

Answer 1

Butylscopolamine or hyoscine
Dicyclomine hydrochloride
Cimetropium bromide

Question 2

Direct smooth muscle relaxants

Answer 2

Mebeverine hydrochloride
Papaverine
Peppermint oil

Question 3

Ca 2+ channel blockers

Answer 3

Alverine
Otilonium bromide (OB)
Pinaverium bromide

Question 4

The most commonly used emetics are;

Answer 4

1. Apomorphine (acts directly on the CTZ)
   2. Ipecacuanha (acts reflexly and directly on the CTZ)

Question 5

Apomorphine

Answer 5

Apomorphine is a semi synthetic derivative of morphine; acts directly on the CTZ as a dopaminergic agonist.

A dose of 6 mg, administered I.M or S.C (within 5 min) induces vomiting.

Oral use of apomorphine is not recommended because a high dose is required with slow and inconsistent action.

Although it may be more effective if water is first administered before oral or subcutaneous dosing.

Excessive dosage may cause respiratory depression and circulatory collapse.

Opioid antagonists such as naloxone usually reverse the depressant actions of apomorphine.

Because of the possibility of respiratory depression, apomorphine is not frequently used as an emetic.

Apomorphine is contraindicated in respiratory or CNS depression

Question 6

Ipecacuanha

Answer 6

Ipecacuanha is obtained from the dried rhizome and roots of Cephaelis ipecacuanha or Cephaelis acuminata, plants in Brazil and Central America that have the alkaloid emetine as their active principal ingredient.

It is administered as ipecac syrup (15-30ml in adults, 10-15 ml in children, 5 ml in infants) for inducing vomit.

It acts directly on the CTZ and also indirectly by irritating the gastric mucosa.

It should be available in every household for emergency.

It is less dependable than parenteral apomorphine and takes 15 minutes or more to produce the effect but is safer.

Ipecac is cardiotoxic if absorbed and can cause cardiac conduction disturbances, atrial fibrillation, or fatal myocarditis.

If emesis does not occur, gastric lavage using a nasogastric tube must be performed

Question 7

Contraindications of Emetics

Answer 7

The patient is unconscious. The patient is likely to aspirate the vomitus because laryngeal reflex is likely to be impaired.

The patient has central nervous system depression .

Corrosive acid or alkali is ingested.

Certain volatile hydrocarbons (Kerosine, petroleum products) are ingested. This can cause more injury to the oesophageal mucosa.

CNS stimulant drug poisoning: it may precipitate convulsion.

6. It is morphine or phenothiazine poisoning: Emetics are ineffective

Question 8

Anti-emetics

Answer 8

Antiemetics may prevent emesis either by blocking the CTZ or by preventing peripheral or cortical stimulation of the vomiting center.

Question 9

Classification of antiemetics

Answer 9

Anticholinergics.

Antihistamines.

5-HT3 receptor antagonists. (Ondansetron, Granisetron, Dolasetron)

Dopamine receptor antagonists. (Metoclopramide, Lorazepam, Haloperidol)

Neurokinin receptor antagonists. (Aprepitant)

Cannabinoid receptor agonists. (Dronabinol)

Question 10

Anticholinergic agents

Answer 10

(Hyoscine, Dicyclomine)
Anticholinergic agents have no role in chemotherapy-induced nausea

Question 11

Antihistamines

Answer 11

(Promethazine, Doxylamine, Cyclizine, Cinnarizine.)

promethazine is useful in treating the nausea and vomiting subsequent cancer chemotherapy

Cyclizine may be useful for patients with abdominal cancer.

Question 12

5-HT3 receptor antagonists

Answer 12

Granisetron, Ondansetron, Dolasetron,

Question 13

Dopamine Antagonists

Answer 13

(Metoclopramide, haloperidol, lorazepam)

Question 14

Cannabinoids

Answer 14

Dronabinol
Nabilone

Question 15

Neurokinin receptor antagonists

Answer 15

aprepitant and fosaprepitant