GI drugs

Question 1

Name two antacids? SEs? Interactions?

Answer 1

Mg trisilicate - diarrhoea
Al hydroxide - constipation

Can both interfere with drug absorption so take separately

Question 2

Name 3 PPIs? MOA? SEs? Interaction? Caution?

Answer 2

Omeprazole
Lansoprazole
Pantoprazole

Activated in acidic pH
Irreversibly inhibit H+/K+ ATPase
More effective cf. H2RAs

hyponatraemia, hypomagnasaemia
osteoporosis → increased risk of fractures
microscopic colitis
increased risk of Clostridium difficile infections

PPIs are P450 inhibitors

Caution: May mask symptoms of gastric Ca.

Question 3

Name 2 H2 receptor antagonists? MOA? SEs? Interactions? Caution?

Answer 3

Cimetidine

reduces gastric parietal cell H+ secretion

GI disturbance

Question 4

Misoprotol MOA? SE? Uses?

Answer 4

prostaglandin analogue, acts on parietal cells to reduce H+ secretion

diarrhoea v common

Mainly used to prevent NSAID-assoc.
Peptic ulcer disease
Often in combination c¯ NSAID

Diclofenac + misoprostol = Arthrotec: helps to relieve the pain and swelling of rheumatoid arthritis and osteoarthritis, and may help to protect patients at risk of irritation or ulceration of the stomach or intestines

Question 5

Name 4 types of laxative? examples of each? MOAs? CI of laxative use?

Answer 5

Bulk-laxatives - Bran ispaghula - ↑ faecal mass → ↑ peristalsis
Stimulant laxatives:
Docusate, Glycerin (PR), Senna, Picosulfate - increased intestinal motility
Osmotic laxatives: Lactulose, Macrogol, Phosphates (PR), Mg Salts - ↑ stool water content
Stool softener: Liquid paraffin

bowel obstruction

Question 6

Co-danthrusate use?

Answer 6

mild stimulant laxative used in Rx of opioid-induced constipation.

Question 7

Hepatic encephalopathy Tx?

Answer 7

Lactulose

Question 8

Liquid paraffin use? SE?

Answer 8

Stool softener

↓ absorption of ADEK vitamins
Granulomatous reactions

Question 9

Hyoscine butylbromide MOA? SE? CIs?

Answer 9

Antimuscarinic - Antispasmodic

SEs: anti-cholinergic effects

Question 10

Mebeverine peppermint oil MOA?

Answer 10

Antispasmodic

Question 11

Loperamide MOA? SEs? CIs?

Answer 11

Opioid receptor agonist - Doesn’t cross BBB so no central effects.
Anti-diarrhoea (used in IBS)

Abdo cramps

CIs: Infective diarrhoea, Colitis, Caution in hepatic
impairment

Question 12

Name two anti-diarhoea tablets?

Answer 12

loperamide

diphenoxylate

Question 13

Name two 5-aminosalicylates? SEs? CI? Monitoring?

Answer 13

Sulfasalazine
Mesalazine

SEs: oligospermia
Stevens-Johnson syndrome
pneumonitis / lung fibrosis
myelosuppression, blood dyscrasias: Heinz body anaemia, megaloblastic anaemia
may colour tears → stained contact lenses

CI: Caution in
G6PD deficiency and
allergy to aspirin or sulphonamides (cross-sensitivity)

Monitor FBC

Question 14

Budesonide MOA? Use?

Answer 14

steroid - more potent than prednisolone

High 1st pass metabolism so ↓
systemic effects.

Used to induce remission in
ileal Crohn’s

Question 15

Name three anti-TNF drugs? SEs? Caution?

Answer 15

Infliximab
Etanercept
Adalimumab

Severe infections
TB
Allergic reactions
CCF
CNS demyelination

CI by TB - Screen for TB before use
give with hydrocortison to reduce allergic SEs

Question 16

Conservative, medical and surgical Mx of GORD?

Answer 16

Conservative: Lose wt.
 Raise head of bed
 Small regular meals ≥ 3h before bed
 Stop smoking and ↓ EtOH
 Avoid hot drinks and spicy food
 Avoid tight clothes
 Stop drugs: NSAIDs, steroids, CCBs, nitrates

Medical: 
OTC antacids: Gaviscon, Mg trisilicate
1st: full-dose PPI for 1-2mo
2nd: double dose PPI
3rd: add H2RA

Surgical: Nissen Fundoplication - 
Indications: all 3 of:
 Severe symptoms
 Refractory to medical therapy
 Confirmed reflux (pH monitoring)

Question 17

Indications of Nissen Fundoplication?

Answer 17

Indications: all 3 of:
 Severe symptoms
 Refractory to medical therapy
 Confirmed reflux (pH monitoring)

Question 18

Investigation for GORD?

Answer 18

Indications for upper GI endoscopy:
age > 55 years
symptoms > 4 weeks or persistent symptoms despite treatment
dysphagia
relapsing symptoms
weight loss

If endoscopy is negative consider 24-hr oesophageal pH monitoring (the gold standard test for diagnosis)

Question 19

Causes of GORD? Complications? Symptoms?

Answer 19

Causes:
Lower oesophageal sphincter hypotension
hiatus hernia, oesophageal dysmotility (eg systemic sclerosis), obesity,
gastric acid hypersecretion, delayed gastric emptying, smoking, alcohol, pregnancy,
drugs (tricyclics, anti cholinergics, nitrates), Helicobacter pylori?

Complications: Oesophagitis, ulcers, benign stricture, iron-deficiency. Barretts oesophagus

Symptoms
Oesophageal: Heartburn (burning, retrosternal discomfort after meals,
lying, stooping, or straining, relieved by antacids)
belching
acid brash (acid or bile
regurgitation)
waterbrash (increased salivation: ‘My mouth fi lls with saliva’);
odynophagia
(painful swallowing, eg from oesophagitis or ulceration). Extra-oesophageal:Nocturnal asthma, chronic cough, laryngitis (hoarseness, throat clearing), sinusitis.

Question 20

Mx of Peptic ulcer disease?

Answer 20

Conservative: Lose wt.
 Stop smoking and ↓ EtOH
 Avoid hot drinks and spicy food
 Stop drugs: NSAIDs, steroids

Medical:
 OTC antacids: Gaviscon, Mg trisilicate
 H. pylori eradication: PAC500 or PMC250
 Full-dose acid suppression for 1-2mo
 PPIs: lansoprazole 30mg mane
 H2RAs: ranitidine 300mg nocte
 Low-dose acid suppression PRN

Surgical: Rarely performed
 Selective vagotomy
 Antrectomy + vagotomy
 Subtotal gastrectomy + Roux-en-Y

Question 21

H-Pylori Ix? Tx?

Answer 21

NB. PPIs and cimetidine → false –ve C13 breath tests
and antigen tests  stop >2wks before.

PAC 500:
 PPI: lansoprazole 30mg BD
 Amoxicillin 1g BD
 Clarithromycin 500mg BD

PMC 250:
 PPI: lansoprazole 30mg BD
 Metronidazole 400mg BD
 Clarithromycin 250mg BD

Failure
 95% success -Mostly due to poor compliance
 Add bismuth - Stools become tarry black

Question 22

Risk factors for peptic ulcer disease? differentiation?

Answer 22

Helicobacter pylori is associated with the majority of peptic ulcers:
95% of duodenal ulcers
75% of gastric ulcers

drugs: NSAIDs, SSRIs, corticosteroids, bisphosphonates

Zollinger-Ellison syndrome: rare cause characterised by excessive levels of gastrin, usually from a gastrin secreting tumour

Duodenal ulcer - more common than gastric ulcers - epigastric pain when hungry, relieved by eating
gastric ulcers: epigastric pain worsened by eating

Question 23

How to treat acute severe UC?

Answer 23

Resus: Admit, IV hydration, NBM
 Hydrocortisone: IV 100mg QDS + PR
 Transfuse if required
 Thromboprophylaxis: LMWH

Monitoring: Bloods: FBC, ESR, CRP, U+E
 Vitals + stool chart
 Twice daily examination
 ± AXR

Improvement → oral therapy: Switch to oral pred + 5-ASA
 Taper pred after full remission

No Improvement → rescue therapy - Medical: ciclosporin, infliximab or visilizumab or Surgical
Discussion between pt, physician and surgeon

Question 24

How to induce remission of UC in mild to moderate disease?

Answer 24

OPD treatment

Oral Tx:
1st line: 5-ASAs
2nd line: prednisolone
3rd line: ciclosporin or infliximab

Topical treatment: for left sided disease mainly
Proctitis: suppositories - More proximal disease: enemas or foams - 5-ASAs ± steroids (prednisolone or budesonide)

Additional Therapy: steroid sparing: Azathioprine or Infliximab: steroid-dependent pts

Question 25

How to maintain remission in UC?

Answer 25

1st line: 5-ASAs PO – sulfasalazine or mesalazine - Topical Rx may be used in proctitis 2nd line: azathioprine or 6-mercaptopurine Relapsed on ASA or are steroid-dependent Use 6-mercaptopurine if azathioprine intolerant  3rd line: infliximab / adalimumab

Question 26

Elective surgery for UC indications? procedures?

Answer 26

Indications  Chronic symptoms despite medical therapy  Carcinoma or high-grade dysplasia Procedures  Proctocolectomy c¯ end ileostomy or IPAA  Total colectomy c¯ (IRA)

Question 27

Mx of Acute severe crohns?

Answer 27

Assessment  ↑temp, ↑HR, ↑ESR, ↑CRP, ↑WCC, ↓albumin Management  Resus: Admit, NBM, IV hydration  Hydrocortisone: IV + PR if rectal disease  Abx: metronidazole PO or IV  Thromboprophylaxis: LMWH  Dietician Review: Elemental diet; Consider parenteral nutrition  Monitoring: Vitals + stool chart, Daily examination Improvement → oral therapy - Switch to oral pred (40mg/d) No Improvement → rescue therapy  Discussion between pt, physician and surgeon  Medical: methotrexate ± infliximab  Surgical

Question 28

How to induce remission in mild or moderate crohns disease?

Answer 28

OPD treatment Supportive  High fibre diet  Vitamin supplements Oral Therapy  1st line: Ileocaecal: budesonide; Colitis: sulfasalazine  2nd line: prednisolone (tapering)  3rd line: methotrexate  4th line: infliximab or adalimumab ``` Perianal Disease  Occurs in ~50%  Ix: MRI + EUA Rx: Oral Abx: metronidazole;  Immunosuppression ± infliximab  Local surgery ± seton insertion ```

Question 29

How to maintain remission in Crohns?

Answer 29

1st line: azathioprine or mercaptopurine  2nd line: methotrexate  3rd line: Infliximab / adalimumab

Question 30

Elective surgery in crohns indications? Procedures?

Answer 30

``` Indications  Abscess or fistula  Perianal disease  Chronic ill health  Carcinoma ``` Procedures  Limited resection: e.g. ileocaecal  Stricturoplasty  Defunction distal disease ¯c temporary loop ileostomy

Question 31

High-risk ABx for C.diff? general and specific Mx of C.diff diarrhoea?

Answer 31

High Risk Abx: Cephalosporins, Clindamycin General: Stop causative Abx; Avoid antidiarrhoeals and opiates; Enteric precautions 1st line: Metronidazole Metronidazole Failure: Vancomycin Severe: Vancomycin (may add metro IV) Urgent colectomy may be needed if: Toxic megacolon, ↑ LDH, Deteriorating condition Recurrence (15-30%): Reinfection or residual spores - Repeat course of metro x 10-14d - Vanc if further relapse (25%) Treatment Failure: Defined as no clinical response after 1wk - C. diff toxin assay will remain positive for ≥2wks following original infection.