1. Gastro-intestinal system Flashcards
Antacids and Alginates
Antacids - Maalox and Mucogel
Alginates - Gavison and Peptac
Counselling
Indications - GORD and dyspepsia (heartburn and indigestion)
S/E - Al = constipation and Mg = diarrhoea
Warnings- Avoid antacids high in Na+ in patients with high BP.
Interactions - Do not take at the time as other drugs as they can impair absorption and damage the EC of other drugs, leave a gap of 2hrs.
Administration - They should be taken following meals, before bed time and/or when symptoms occur.
Dose - 10-20ml after meals and at bedtime
Antimuscarinics
Dicycloverine &Hyoscine butylbromide (Buscopan)
Counselling
Indications - IBS & diverticular disease
S/E -Constipation, tachycardia, urinary urgency and retention, blurred vision, photophobia, dry mouth, flushing and dryness of the skin.
Interactions - S/E are more pronounced when taken in combination with other drugs that have antimuscarinic effects eg TCA.
Dose: Dicycloverine 10-20mg TDS
Hyoscine butylbromide (Buscopan): 10 mg TDS increased if required up to 20 mg 4 QDS
Other antispasmodics
Alverine (Spasmonal), Mebeverine (Colofac) & peppermint oil (MINTEC & COLPERMIN)
Counselling
Indications - IBS & diverticular disease.
Dose: Mebeverine (Colofac) 135-150mg TDS preferably 20 min before meals whereas (Colofac MR) 1 BD preferably 20 min before meals
Peppermint oil 1-2 capsules whole with water TDS before meals for up to 3 months if necessary
H2 receptor antagonists
Cimetidine, Famotidine, Nizatidine & Ranitidine (Zantac)
Counselling
Indications - Healing of gastric and duodenal ulcers & GORD.
S/E - Diarrhoea, headache and dizziness. (Cimetidine- gynaecomatia “man boobs” and impotence)
Interactions - Cimetidine inhibits P450 and therefore interacts with warfarin, phenytoin and theophylline.
Dose: Cimetidine 400mg BD or QDS, Famotidine 40mg ON up to 40mg BD, Nizatidine 150-300mg BD and Ranitidine 150mg BD for 2wks.
Prostaglandin analogues
Misoprostol
Counselling
Indications- Prevention of NSAID associated ulcers, especially in elderly patients were the NSAID can’t be withdrawn.
S/E- Diarrhoea
Warnings- Misoprostol should not be used in women of childbearing age unless pregnancy has been excluded.
Pregnancy: avoid—potent uterine stimulant (has been used to induce abortion); teratogenic risk in first trimester.
Dose: Misoprostol 200mcg QDS
Proton pump inhibitors (PPI)
Esomeprazole (Nexium), Lansoprazole, Omeprazole (Losec) & Rabeprazole Sodium (Pariet)
Counselling
Indications - Dyspepsia and GORD. Prevention and treatment of NSAID associated ulcers & the Eradication of H. pylori infection
S/E - Nausea and vomiting, abdominal pain, flatulence, diarrhoea, constipation and headache.
Warnings - May mask the symptoms of gastric cancer. Patients at risk of osteoporosis may need Ca+2 and vitamin D supplements.
Also risk of hypomagnesaemia - arrhythmia.
Interactions - Omeprazole decreases the antiplatelet effect of clopidogrel by decreasing its activation by p450 enzymes. However, it enhances the anticoagulant effect of warfarin.
Dose: 10-40mg OD
Anti-motility drugs
Loperamide (Imodium) & co-phenotrope
Counselling
Indication - Diarrhoea in IBS or viral gastroenteritis.
S/E - Nausea, abdominal cramps, constipation and flatulence.
Warnings -Avoid in acute ulcerative colitis, clostridium difficile colitis and acute bloody diarrhoea.
Dose: Loperamide 2mg - Take two now and then take one after each loose stool for up to five days. (Max of 8 per day)
Aminosalicylates
Salfasalazine, Balsalazide, Mesalazine (Pentasa) & Olsalazine
Counselling
Counselling
Indications - Ulcerative colitis (Melsalazine) and Rheumatoid arthritis (Salfasalazine).
S/E - Diarrhoea, nausea, vomiting, abdominal pain, exacerbation of symptoms of colitis, headache, hypersensitivity reactions (including rash and hives).
Warnings - Aminosalicylates should be avoided in salicylate (aspirin) hypersensitivity.
Blood disorders
Patients receiving aminosalicylates should be advised to report any unexplained bleeding, bruising, purpura (purple coloured spots), sore throat, fever or malaise (general feeling of discomfort/illness) that occurs during treatment. A blood count should be performed and the drug stopped immediately if there is suspicion of a blood dyscrasia.
Interactions - Mesalazine tablets with a pH sensitive coating may interact with drugs that affect gut pH eg PPI and lactulose.
Counselling - Sulfasalazine colours bodily fluids yellow/orange, may also stain some soft contact lenses.
Aminosalicylates
Salfasalazine, Balsalazide, Mesalazine (Pentasa) & Olsalazine
Dose
Dose
Balsalazide take 3 TDS during an acute attack and 2 BD for maintenance
Mesalazine up to 4g daily in divided doses and 2g OD for maintenance
Olsalazine 1g TDS during an acute attack and 500mg BD for maintenance
Sulfasalazine 1-2g QDS in an acute attack, reducing to a maintenance dose of 500mg QDS
Bulk-Forming Laxatives (eg Ispaghula husk- Fybogel)
Considered to be the safest type of laxative.
S/E: abdominal distension and flatulence.
Warnings: avoid in intestinal obstruction, faecal impaction and ileus.
Should be carefully taken with water and not be taken immediately before going to bed.
Recommended as first line therapy in pregnancy.
Onset of action: 12 – 72 hour.
Dose: Take 1 sachet in water BD after meals
Stimulant Laxatives (eg Senna, Docusate sodium)
Very effective and relatively fast-acting.
S/E: abdominal pain and flatulence.
Warnings: avoid in intestinal obstruction.
Not recommended to use for more than one week.
Onset of action: 6 – 12 hours.
Dose: Docusate sodium 500mg daily in divided doses & Senna Take 2-4 at night
Osmotic Laxatives (eg Laclutose, Macrogol oral powder -Movicol)
Work by retaining fluid in the large bowel by osmosis.
S/E: flatulence, abdominal cramps and nausea.
Warnings: avoid in intestinal obstruction.
Onset of action: 24 – 48 hours.
Lactose is first line for children
Dose: Movicol 1-3 sachets in divided doses & Lactose 15ml BD
