Prokinetic Drugs

PROKINETIC DRUGS

Q. 1

Drug not used in H. pylori :

 A

Metronidazole

 B

Omeprezole

 C

Mosapride

 D

Amoxicillin

Q. 1

Drug not used in H. pylori :

 A

Metronidazole

 B

Omeprezole

 C

Mosapride

 D

Amoxicillin

Ans. C

Explanation:

Mosapride[Ref. Harrison 16th/e p 888]

RECOMMENDED TREATMENT REGIMEN FOR HELICOBACTER PYLORI :

Regimen duration

Drug 1

Drug 2

Drug 3

Drug 4

1st line treatment

 

 

 

 

Regimen 1

OCA (7 days)

Omeprazole

Clarithromycin

Amoxicillin

 

Regimen 2

OCM (2 days)

Omeprazole

Clarithromycin

Metronidazole

 

2nd line treatment

 

 

 

 

Regimen 3

OBTM (14 days)

Omeprazole

Bismuth

Tetracycline

Metronidazole

Mosapride is a 5-HT4 agonist used for GERD. Stimulation of 5-HT4 receptors on the presynaptic terminal of submucosal intrinsic primary afferent nerves enhances the release of their neurotransmitters, including calcitonin gene-related peptide, which stimulate second-order enteric neurons to promote the peristaltic reflex. These enteric neurons stimulate proximal bowel contraction (via acetylcholine and substance P) and distal bowel relaxation.

Drugs useful for H. Pylori infection

o Amoxicillin                                                    o Tetracycline

o Tinidazole/metronidazole                               o Bismuth

o Omeprazole                                                 o Clarithromycin

o Ranitidine



Q. 2

All the following statements regarding interactions of levodopa are correct except –

 A

In Parkinsonism, phenothiazines reduce its efficacy

 B

It is a prodrug

 C

Pyridoxine reduces effect of levodopa in parkinsonism

 D

Domperidone blocks levodopa induced emesis and its therapeutic potential

Q. 2

All the following statements regarding interactions of levodopa are correct except –

 A

In Parkinsonism, phenothiazines reduce its efficacy

 B

It is a prodrug

 C

Pyridoxine reduces effect of levodopa in parkinsonism

 D

Domperidone blocks levodopa induced emesis and its therapeutic potential

Ans. D

Explanation:

Ans. is ‘d’ i.e., Domperidone blocks levodopa induced emesis and it’s therapeutic potential

`When domperidone is administered with levodopa or bromocriptine, it counteracts their dose limiting emetic action, without affecting the therapeutic effect in Parkinsonism’                                    

Levodopa is a prodrug, inactive by itself but is the immediate precursor of the transmitter dopamine.


Q. 3

Metoclopramide is useful for all except –

 A

Motion sickness

 B

Chemotherapy induced vomiting

 C

Antiemetic

 D

All

Q. 3

Metoclopramide is useful for all except –

 A

Motion sickness

 B

Chemotherapy induced vomiting

 C

Antiemetic

 D

All

Ans. A

Explanation:

Ans. is ‘a’ i.e., Motion sickness

o Metoclopramide can be used as an antiemetic in postoperative, drug induced, disease associated, radiation sickness,

but is less effective in motion sickness.

o It should not be used to augment lactation. Though the amount secreted in milk is small, but suckling infant may develop loose motions, dystonia, myoclonus.

Quiz In Between


Q. 4

Prokinetic drug with extrapyramidal side effect is?

 A

Cisapride

 B

Domperidone

 C

Ondansetron

 D

Metoclopramide

Q. 4

Prokinetic drug with extrapyramidal side effect is?

 A

Cisapride

 B

Domperidone

 C

Ondansetron

 D

Metoclopramide

Ans. D

Explanation:

Ans. is ‘d’ i.e., Metoclopramide

o Metaclopramide can prodce extrapyramidal side effects due to D2 blockade action.


Q. 5

A prokinetic drug which lacks D2 receptor antagonistic action is which one of the following‑

 A

Metoclopramide

 B

Domperidone

 C

Cisapride

 D

Chlorpromazine

Q. 5

A prokinetic drug which lacks D2 receptor antagonistic action is which one of the following‑

 A

Metoclopramide

 B

Domperidone

 C

Cisapride

 D

Chlorpromazine

Ans. C

Explanation:

Ans. is ‘c’ i.e., Cisapride

o Cisapride has 5-HT4 agonistic activity (without any D2 blocking activity).


Q. 6

The commonest side-effect of Cisapride is –

 A

Abdominal cramps

 B

Diarrhea

 C

Headache

 D

Convulsions

Q. 6

The commonest side-effect of Cisapride is –

 A

Abdominal cramps

 B

Diarrhea

 C

Headache

 D

Convulsions

Ans. B

Explanation:

Ans. is ‘b’ i.e., Diarrhea

Cisapride is a prokinetic agent and often produces loose stools (diarrhea is thus the commonest side effect)

Quiz In Between


Q. 7

Drug implicated for prolongation of QT interval in a premature baby is –

 A

Domperidone

 B

Metoclopramide

 C

Cisapride

 D

Omeprazole

Q. 7

Drug implicated for prolongation of QT interval in a premature baby is –

 A

Domperidone

 B

Metoclopramide

 C

Cisapride

 D

Omeprazole

Ans. C

Explanation:

Ans. is ‘c’ i.e., Cisapride

Cisapride is a non-selective serotonin 5HT4 agonist and partial 5HT3 antagonist.

This drug accelerates gastric emptying, so it is used in patients with Gastro Esophageal Reflex Disease (GERD).

One of the rare complications includes QT prolongation in ECG, ventricular dysarrthymias and sudden death.

Cisapride inhibits the delayed rectifying IC- channels in heart and can cause prolongation of QT interval. o Drugs inhibiting CYP3A4 enzyme can precipitate Torsaes DePointes, Caused by cisapride eg; clarithromycin, erythromycin, cyclosporine, fluconazole, itraconazole, ketoconazole, Nefazodone, Ritonavir, Fluvoxamine.

The drug has been withdrawn from most countries.

Ref: Henry P. Parkman, Richard W. McCallum (2012)  Chapter 22, “Prokinetic Agents for Gastroparesis”, In the  book, “Gastroparesis: Pathophysiology, Presentation and Treatment”, Springer Publications, Newyork, Page 267 ; Katzung, 9th Edition, Page 1046


Q. 8

Patient is on Cisapride for gastroesophageal reflux develops upper respiratory tract infection, and physician prescribes erythromycin. What pharma­logical interaction would be expected –

 A

Dereased level of erythromycin and exacerbation of URTI

 B

Decreased effect of cisapride due to enzyme inductor of erythromycin

 C

Fatal ventricular arrhythmia

 D

Hemorrhagic cystitis

Q. 8

Patient is on Cisapride for gastroesophageal reflux develops upper respiratory tract infection, and physician prescribes erythromycin. What pharma­logical interaction would be expected –

 A

Dereased level of erythromycin and exacerbation of URTI

 B

Decreased effect of cisapride due to enzyme inductor of erythromycin

 C

Fatal ventricular arrhythmia

 D

Hemorrhagic cystitis

Ans. C

Explanation:

Ans. is ‘c’ i.e., Fatal ventricular arrythmia


Q. 9

All of the following drug may be used for motion sickness except –

 A

Hyoscine

 B

Dicyclomine

 C

Domperidone

 D

Scopolmine

Q. 9

All of the following drug may be used for motion sickness except –

 A

Hyoscine

 B

Dicyclomine

 C

Domperidone

 D

Scopolmine

Ans. C

Explanation:

Ans. is ‘c’ i.e., Domperidone

o Drugs used are :

a)         Anticholinergics —> Hyoscine (Scopolamine), Dicyclomine.

b)      Hl-antihistaminic —> Promethazine, cyclizine, meclizine, cinnarizine, etc.

o Hyoscine (scopolamine) is the most effective drug for motion sickness.

About option ‘c’

o Domperidone is a prokinetic drug and acts by D2 blockade. It is ineffective in motion sickness as vestibular pathway does not involve dopaminergic link.

Quiz In Between


Q. 10

Which of the following is a prokinetic drug with no dopamine antagonism:         

March 2005

 A

Chlorpromazine

 B

Metaclopramide

 C

Domperidone

 D

Mosapride

Q. 10

Which of the following is a prokinetic drug with no dopamine antagonism:         

March 2005

 A

Chlorpromazine

 B

Metaclopramide

 C

Domperidone

 D

Mosapride

Ans. D

Explanation:

Ans. D: Mosapride

Metoclopramide is a dopaminergic antagonist and peripheral serotonin receptor antagonist with GI and CNS effects Cisapride is chemically related to metoclopramide, but unlike metoclopramide, it does not cross the blood-brain barrier or doesn’t have antidopaminergic effects. Therefore, it does not have antiemetic action or cause extrapyramidal effects (extreme CNS stimulation).

Mosapride is a new congener of cisapride with similar gastrokinetic and LES tonic action due to 5-HT4 agonistic (major) and 5-HT3 antagonistic (minor) action in the myenteric plexus, but has not caused Q-Tc prolongation or arrhythmias. Like cisapride, it has no clinically useful antiemetic action and does not produce extrapyramidal/hyperprolactinemic side effects due to absence of D2 blocking property.

Domperidone is a peripheral dopamine receptor antagonist


Q. 11

Commonest side effect of cisapride

 A

Abdominal cramps

 B

Headache

 C

Diarrhea

 D

Convulsions

Q. 11

Commonest side effect of cisapride

 A

Abdominal cramps

 B

Headache

 C

Diarrhea

 D

Convulsions

Ans. C

Explanation:

Ans. is ‘c’ i.e., Diarrhoea


Q. 12

Which of the following is a prokinetic drug‑

 A

Domperidone

 B

Cimetidine

 C

Ondansetron

 D

Hyoscine

Q. 12

Which of the following is a prokinetic drug‑

 A

Domperidone

 B

Cimetidine

 C

Ondansetron

 D

Hyoscine

Ans. A

Explanation:

Ans. is ‘a’ i.e., Domperidone

Gastrokinetic (prokinetic drugs)

  • These are the drugs which promote gastrointestinal transit and speed gastric emptying by enhancing coordinated propulsive motility.
  • Prokinetic drugs are → Metoclopramide, Domperidone, Cisapride, Mosapride, Tegaserod, renzapride, prucalopride.

Pathophysiology of gastrokinetic drugs :

  • Acetylcholine is the major neurotransmitter in the GIT which is responsible for the peristaltic movement.
  • Its secretion is affected by other neurotransmitter also ‑
  1. Activation of prejunctional excitatory 5-HT, receptors increases the release of Ach.
  2. Activation of prejunctional inhibitory D2 and 5-HT, receptors inhibits the release of Ach.
  • So, prokinetic drugs can act by ‑
  1. 5HT4 agonistic activity
  2. D2 and 5-HT3 antagonistic activity
  • Both these action will increase the release of Ach and there by motility of GIT.

Quiz In Between



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