Gastrointestinal Drugs

Question 1

Ppi 
- esomeprazole
Omeprazole 
Pantaprazole
Lansoprazole

Answer 1

1st line - more effective than h2 anatogonist

Moa -
Irreversibly inactivate the h+/ k+ atpase proton pump suppress both stimulated and basal acid secretion

Se

• well tolerated
• cautions in hepatic impairment
• git symptoms, vit b 12 deficiency,
• long term use: gynaecomastia, decrease ca reabsorption -> increase #

Dose - 40mg daily bd

Question 2

H. Pylori eradication regimens?

Answer 2

Triple therapy - 7 days

• clarithromycin 500 mg bd
• amoxycillin 1g bd
• ppi- 40 mg bd

Replace amox or clarithromycin with 400 mg metronidazole bd if unsuitable

Quadruple therapy - 10-14 days ( not aus)
- ppi, bismuth subcitrate, metronidazole, tetracycline/doxycycline

Question 3

5asa

- sulfasalazine, mesalazine

Answer 3

5 amino salicylate acid

Moa- aminosalicylate that collects in git, nf kappa b (controls DNa transcription) inhibition and free radical scavenging

Se:
Pancreatitis, bloody dyscrasia
Sulfasalazine - reversible male infertility, orange discolouration, fibrosis alveolitis, meningitis

Ci if allergic to sulphonamides
Safe in pregnancy (give folic acid)

Monitor urinalysis, lft, fbc baseline every 2 weeks for 3 months then 6 months

Indicated for Crohns or uc

Question 4

Tnf a antagonist

• adalimumab
• infliximab

Answer 4

Moa - bind to tnf alpha and inhibits (tnf alpha is a cytokines involved in inflammatory and immune response - pathology of ra, psoriasis, ibd, ankylosis spondylitis, jia)

Ci: demyelinating disease and hf (exacerbation), another cytokines modulator (increase infection risk), interstitial lung disease, sle, lymphoproliferative or melanoma

Immunosuppressive therefore can reactiviate hep b, latent tb (immunise before use)

Se: infections, eczema, malignancies, demyelination, interstitial lung disease, drug lupus, hf

Monitor: fbc, alt, ast, uec,
Check tb, hep b, skin cancer

Question 5

Ibs management of symptoms

• constipation
• diarrhoea
• colic and bloating
• dyspeptic symptoms

Answer 5

• constipation - high fibre, fybogel, stool softener (sodium docusate)
• diarrhoea - bulking agent, loperamide (opiod antimotility)
• colic and bloating - mebeverine (antimuscatinic, relax gut muscles with no anticholinergic side effect)
• dyspeptic symptoms - metoclopramide (dopamine receptor anatogonist), antacid

Question 6

H2 antagonist

• cimetidine
• ranitidine

Indication?
Moa
Side effect 
Dose
Caution?

Answer 6

Moa - competitively block h2 receptor on parietal cells (work on basolateral surface), reduce gastric acid secretion

Indicated for pud, gord, dyspepsia, prophylaxis for stress ulcer

Se

• quite a safe drug, rarely can cause hypotension, thrombocytopenia, hepatitis, hypersensitivity
• careful dosing in renal impairment
• anti androgenic effect: gynaecomastia, galactorrhoea, impotence, decrease libido, cns effect

Dose
- ranitidine 300mg Po evening daily (pud, gord)
Or 150 mg Po daily (dyspepsia, prophylaxis)