Gi Pharmacology

Question 0

Give the name of some proton pump inhibitors

Mechanism, use, toxicity of proton pump inhibitors

Answer 0

Omeprazole lansoprazole

Irreversibly inhibits H+/K+ ATPase @Parietal cells

For peptic ulcers, gastritis, oesophageal reflux, Zollinger Ellison syndrome

Toxicities = increased risk of C. difficile, pneumonia, decreased serum Mg2+

Question 1

Give the name of someone H2-blockers
Mechanism?
Clinical use?
Toxicity?

Answer 1

Cimetidine ranitidine famotidine nizatidine

Peptic ulcer, gastritis, mild oesophageal reflux

CCCCimetidine = CCAp
inhibit CCCCytochrome p 450
Cross blood-brain barrier + cross placenta
Antiandrogenic = prolactin release, impotence, gynaecomastia, decreased libido

CCCimetidine + RRRanitidine =
Decrease CCCreatinine RRRenal excretion

Question 2

What is the mechanism of business and sucralfate and what is its clinical use ?

Answer 2

Binds to also base = physical protection
Allowed bicarb secretion ->
re-establish pH gradient @mucus layer

For ulcer healing + Travellers diarrhoea

Question 3

What is Misoprostol?
Mechanism?
Use?
Toxicity?

Answer 3

Prostaglandin E1 analogue =
produce & secrete gastric mucus barrier
+
decrease acid production

Use = prevent NSAID induced peptic ulcer Slimed maintain PDA
Induced labour by ripening cervix

Toxicity = diarrhoea

Question 4

Give the name of a long acting somatostatin analogues

Mechanism? Use? Toxicity?

Answer 4

Octreotide

Inhibit action of splanchnic vasoconstriction hormones

Carcinoid tumours, Acute variceal bleed, VIPoma, Acromegaly

Toxicity = nausea cramps steatorrhea

Question 5

How do antacids affect other drugs?

Problems with aluminium hydroxide calcium carbonate and magnesium hydroxide

Answer 5

Affect absorption bioavailability and urine excretion

Aluminium hydroxide =
constipation hypophosphataemia, osteodystrophy, proximal muscle weakness, seizures

Calcium carbonate = hypocalcaemia

Magnesium hydroxide =
cardiac arrest, hypo reflex/tension, diarrhoea

Question 6

Types of osmotic laxatives?
Mechanism?
Use?
Toxicity?

Answer 6

Provide osmotic load – >draw water into GI Newman

Use = constipation
Lactulose = for hepatic encephalopathy: 
Lactulose breakdown by good flora ->
Lactic acid + acetic acid – > 
promotes N excretion = NH4+

Toxicity = diarrhoea and dehydration

Question 7

Mechanism of sulphasalazine
Use?
Toxicity?

Answer 7

Sulphasalazine = 
sulfapyrifine (antibacterial)
 \+ 
5 aminosalicylic acid (any anti-inflammatory)
 -> activated by colonic bacteria

Use = ulcerative colitis and crohns

Toxicity cause malaise nausea oligospermia

Question 8

Ondansetron mechanism use toxicity?

Answer 8

Five HT three antagonist = decrease vagal stimulation = central acting antiemetic

Used to control vomiting post operatively + chemo

Toxicity =
constipation
headache
increased Q-T interval

Question 9

Mechanism use and toxicity of orlistat?

Answer 9

Inhibits gastric + pancreatic lipase – >
decrease breakdown + decreased absorption of fats

Use equals weight loss

Toxicity =
steatorrhea +
decreased absorption of fat-soluble vitamins

Question 10

Mechanism of metoclopramide

Use? Toxicity?

Answer 10

D2 receptor antagonist
Increased motility, resting town, contractility, oesophageal sphincter tone

use = antiemetic + gastroparesis (diabetic + post surgery)

Toxicity = Parkinsonian effect, restless, drowsy, fatigue, depressed, diarrhoea, tardive dyskinesia

Contraindications = don’t take with the DIGOXIN or if have small-bowel obstruction/Parkinson’s disease

Question 11

What is infliximab What is this use and toxicity?

Answer 11

Monoclonal antibody to TNF alpha

Use = crohns ulcerative colitis rheumatoid arthritis ankylosing spondylitis psoriasis

Toxicity = infection Fever hypotension

Question 12

Patients is sick after a car ride is alsosick due to some sort of stomach irritant is also pregnant what drugs can you give Her?

Answer 12

Histamine one antagonists = Cinnarizine cyclizine promethazine

Also give ACh M receptor antagonist = hyoscine
gets dry mouth and learning as well

Question 13

If a patient is on fluorouracil etoposide methotrexate vinca Alkaloids or abdominal radiotherapy what symptom of a likely to suffer from? What severity Is the emetogenicity?

Answer 13

Nausea and vomiting

Mildly emetogenic give dopamine antagonist

Question 14

Is a patient on taxanes doxorubicin Cyclophophamide mitoxantrane methotrexate what symptom is the patient likely to suffer from? What severity Is the emetogenicity?

Answer 14

Nausea and vomiting

Moderately emetogenic give dexamethasone/Lorazepam

Question 15

If a patient is on cisplatin dacarbazine and Cyclophophamide made what symptoms the patient likely to suffer from? What severity Is the emetogenicity?

Answer 15

Nausea and vomiting

Highly emetogenic give 5HT3 antagonist or neurokinin antagonist

Question 16

Patient has chronic constipation What drug can you give?

Answer 16

5 HT for agonist prucalopride = 5 HT stimulates ACh release + myenteric plexus

Question 17

What is iopromide/Imodium used for ?

Answer 17

Decreases abdominal cramps + slow faeces passage – > for diarrhoea

Question 18

Patient has spasming due to IBS + diverticuli disease what can you give them and what side-effects would you get ?

Answer 18

Muscarinic antagonists

Side effects = drymouthed blurry vision