GIT drugs Flashcards
(28 cards)
What meds can cause GORD?
NSIADS: Aspirin and ibuprofen
What meds are used to treat GORD?
Antacids
H2 receptor blockers
proton pump inhibitors
What does the drug management of acid-related disease aim at?
- Reducing gastric acid secretion with H2-receptor antagonists, proton pump inhibitors
- Neutralizing secreted gastric acid with antacids
- Increase mucosal resistance to acid-pepsin attacks with Misoprostol ( synthetic prostaglandin E1)
- Eradicating H. pylori
What is the function of antacids?
To neutralise secreted acid
What does antacids consist of?
Aluminium hydroxide, magnesium hydroxide and sodium bicarbonate
What is the mechanism of action of antacids?
- Antacids consist of alkaline Al3+, Mg 2+ and Na+ salts that are used to raise the luminal pH of the stomach
- They neutralize acid and as a result, may reduce the damaging effects of pepsin which is pH dependent.
- Additionally, Al3+ and Mg 2+ salts bind and inactivate pepsin
- Route of administration: Oral
What is alginates and an example of it?
- Alginate containing antacids (e.g. Gaviscon) are administered orally
- Form an impenetrable raft that floats on the surface of the gastric contents
What are autacoids?
Autocoids are substances that are called into play in the defence of the body.
Their importance lies mainly in their roles in inflammation and allergic responses.
- Not released or stored in glands.
- Not circulated in blood.
- Are formed at the site of action.
- Produce localized action.
examples of autacoids
Amine autacoids:
- Histamine, 5-Hydroxytryptamine (serotonin)
Lipid derived autacoids:
- Prostaglandins, leukotrienes, platelet activating factor (PAF)
Peptide autacoids
- Plasma kinins (bradykinin, kallidin), angiotensin
How does H2 receptor antagonists work?
- They bind to the H2-receptors on the cell membranes of parietal cells
- Prevent histamine induced stimulation of gastric acid secretion
What are the agents of H2 receptor antagonists?
cimetidine
Ranitidine
Examples of proton pump inhibitors
Omeprazole; Lansoprazole; Pantoprazole; Esomeprazole
What are the regimes for H. Pylori eradication?
- Classic therapy: omeprazole, metronidazole, amoxycillin or clarithromycin for 1 or 2 weeks. 90% elimination, but compliance, resistance and adverse effects!
- Dual therapy: Omeprazole + single anti-biotic, amoxycillin or Clarithromycin
What is Antiemetics?
drugs that treat nausea and vomiting
What are the different classes of antiemetics?
- Dopamine Receptor Antagonists
- 5HT3 (serotonin) antagonists
- Antimuscarinic drugs
- Antihistamines
- Substance P antagonists
- Cannabinoids
What are the classes of drugs are used for GI motility?
- Motility stimulants
- Antispamodics
- Laxatives
- Antidiarrhoeals
Examples of Motility stimulants and their effects.
- Domperidone and metoclopramide
- increase intestinal motility, enhance the peristaltic contractions of the oesophageal body, increase the muscle tone of the lower oesophageal sphincter, and stimulate gastric motor activity.
Example of antispasmodic drug
Mebeverine
What are the different classes of laxatives?
- Bulk-forming agents
- Osmotic laxatives
- Stimulant laxatives
- Stool softeners
Examples of bulk forming agents
Natural:
- Dietary Fiber
- Psyllium
Synthetic:
- Polycarbophil
- Methylcellulose
Examples of osmotic laxatives
Poorly absorbed salts (Saline laxatives)
- Magnesium Sulphate (Epsom Salts)
- Magnesium Hydroxide (Milk of magnesia)
Poorly absorbed sugars
- Lactulose
- Glycerine
examples of stimulant laxatives
Diphenylmethane derivatives:
- Bisacodyl (Dulcolax)
- Sodium Picosulphate
Ricinoleic
- Castor oil
Anthraquinones:
- Senna (Senokot)
Examples of stool softeners
Docusate sodium
Liquid paraffin
Examples of Anti-microbial drugs for diarrhoea
- Tetracycline
- Ciprofloxacin
