Drugs of the GI Tract Flashcards
Name examples of 5ASAa
- sulphasalazine
- mesalazine
- osalazine
- balsalazide
what does the site of release of 5ASA depend on
- when given orally the site of release of 5ASA depends on formluation (coating and azo-bond)
what are the indications for 5ASAs
- Mild/moderate UC
- colonic crohns
- maintenance UC - prevents recurrence of
What is the mechanisms of action of 5ASA
- they are poorly absorbed
- effects are largely topical
- unknown mechanism of action
What do they think is the mechanism of action of 5ASAs
- scavengers of ROS
- modulates prostaglandins and leukotriene synthesis from arachidonic acid
- modulates cytokine profile
- PPARgamma (peroxisome proliferator activated receptor gamma) agonists
What are the side effects of 5ASA
- nephrotoxicity
- rash
- worsening of colitis
- pancreatitis
- pericarditis
what are the classes of corticosteroids
- Glucocorticoid
- low mineralocorticoid
What are the names of corticosteroids
- Prednisolone
- Hydrocortisone
- budesonide
describe budesonide
- topical action
- first pass metabolism
- fewer systemic side effects
What is the indication for corticosteroids in UC
- induction of remission
What is the mechanism of action of corticosteroids
- immunosuppressive
- mediated via glucocorticoid receptor
- regulates transcription of 100+ genes
- reduces IL-1, TNF alpha, IL-8
- reduces nitric oxide
- prevents leucocyte migration
What is the route of administration for corticosteroids
Depends according to site and severity of IBD
- oral
- IV
- Enema
- suppositories
What are the side effects of corticosteroids
- Hypertension
- diabetes mellitus
- central obesity
- osteoporosis, myopathy
- acne, bruising
- cataracts
- depression
- growth failure
- pituitary/adrenal suppression
what causes duodenal peptic ulcer disease
Helicobacter pylori
What causes gastric peptic ulcer disease
- Helicobacter pylori
- NSAIDs and steroids
What are the classes of anti-secretory therapy
- Proton pump inhibitors
- histamine receptor 2 antagonists
what are the names of proton pump inhibitors
- Omeprazole
- lanzoprazole
- pantoprazole
- rabeprozole
- esomeprazole
Name some examples of histamine receptor 2 antagonists
- Ranitidine
What is the indication for anti secretory therapy
- PUD
- GORD
- prevention of ulcers in patients on NSAID
- Zollinger ellison syndrome
what is zollinger ellison syndrome
Zollinger–Ellison syndrome (Z-E syndrome) is a disease in which tumors cause the stomach to produce too much acid, resulting in peptic ulcers
What is the route of admission for an anti-secretory therapy
- oral
- IV
What are the side effects for anti-secretory therapy
- Diarrhoea
- headache
- increase risk of C.difficile
- weak inhibitors of cytochrome P450 (care with phenytoin, warfarin and theophyline)
Name the three emetic pathways
- Medulla
- afferents - labyrinth, vagus, systemic circulation
- Efferents - oesophagus, stomach, abdominal wall
What are the three classes of anti emetics
- H1r anatognists
- D2r antagonists, 5HT4r agonist
- 5HT3 antagonists
Name a H1r anatognists
Cyclizine
What are the indications of use of Cyclizine (H1r anatognists)
- Vertigo
- motion sickness
- post-op nausea and vomiting
What are the side effects of Cyclizine (H1r anatognists)
- drowsiness
- dry mouth
- urinary retention
Name a D2r antagonists, 5HT4r agonist
Metoclopramide
Name some indications for Metoclopramide (D2r antagonists, 5HT4r agonist)
- Anti-emetic
- gastroparesis
- PONV
Name the mechanism of action of metaclopramide (D2r antagonists, 5HT4r agonist)
- CTZ
- increases gastric emptying
Name the side effects of metaclopramide (D2r antagonists, 5HT4r agonist)
- restlessness
- dystonic reactions
Name an example of a 5HT3 antagonists
Ondansetron
name the indications for ondansetron (5HT3 antagonists)
- refractory
- PONV
- chemotherapy
name the side effects for ondansetron (5HT3 antagonists)
- constipation
- headache
- flushing
- reduced HR
- reduced BP
describe how thiopurines can have different effects on the body
Azathiopurine can be converted into mercaptopurine (MP)
- TPMT can covert this to methyl mercaptopurine (MMP) this causes liver damage
Or
- meracaptopurine (MP) can be converted into thioguanine this can have a therapeutic effect but also can cause bone marrow suppression
Name some examples of thiopurines
- azathioprine
- mercaptopurine
how are thiopurines taken
- oral
What are the indications of thiopurines
maintenance of remission of IBD
What are the side effects of thiopurines
- bone marrow suppression
- hepatitis, pancreatitis
- lethargy, headache, nausea, rash
- viral infections
- lymphoma
What is regularly checked when using thiopurines
- blood count
- LFTs
- drug levels (TGN)
What is pre checked when using thiopurines and wh y
- TPMT status
this is because TMPT can convert mercaptopurine (MP) to methyl mercaptopurine (MMP) this causes liver damage
name 4 classes of laxatives
- Bulk laxative
- stimulant laxative
- stool softener
- osmotic laxative
Name an - example - mechanism of action - side effect for a bulk laxative
example
- Fybogel
mechanism of action
- increases stool mass
- stimulates peristalsis
side effect
- wind
- bloating
Name an - example - mechanism of action - side effect for a stimulant laxative
example
- Senna
mechanism of action
- increases colonic motility
side effect
- cramps
- low potassium
Name an - example - mechanism of action - side effect for a stool softener
example
- arachis oil
mechanism of action
- lubricates stool
side effect
- peanut allergy
Name an - example - mechanism of action - side effect for a osmotic laxative
example
- lactulose
- movicol (macrogol)
mechanism of action
- Lactulose = disaccarhide not absorbed, draws fluid into the gut lumen
- Movicol = not absorbed, draws fluid into the gut lumen
side effect
- Lactulose = wind and cramps
Name the classes of biologicals that can be used
- Anti TNF
- Anti integrin
- Anti IL-12/23
- JAK inhibitors
Name some examples of Anti TNF
- infliximab
- adalimumab
Name some examples of Anti integrins
- vedolizumab
Name some examples of Anti IL-12/23
- ustekinumab
Name some examples of JAK inhibitors
- Tofacitinib (oral, UC only)
How are biological treatments in IBD given
- IV or SC
- tofacitinib is given orally
What are biologicals used in
- IBD
- rheumatoid arthritis
- ankylosing spondylitis
- psoriasis
What are the side effects of biologicals
- opportunistic infections
- hypersensitivity reactions
- loss of response due to development of antibodies
What drugs are used in induction of remission in IBD
1st line
- 5ASA (UC)
- Corticosteroids
- Ciclosporine (UC)
3rd line
Biologicals
What drugs are used in. maintenance of remission in IBD
1st line
- 5ASA (UC)
2nd line
- thiopurines
- methotrexate
3rd line
- Biologicals
