Drugs used in gastrointestinal tract

Drugs used in GIT

•Drugs used in oral infections.•Treatment of peptic ulcer.•Treatment of constipation.•Treatment of diarrhea.•Drugs used in the treatment of irritable

bowel syndrome (IBS).•Antiemetic agents.•Drugs used to treat inflammatory bowel

disease (IBD).

Drugs used in oral infections.

•Dehydration must be avoided.•If dry mouth is a special problem,

various artificial salivas are available.

•Mouthwashes used to prevent and treat oral infections:▫Thymol.▫Chlorhexidine gluconate (0.2% solution and

as 1%dental gel).▫Hydrogen peroxide (hospitals used

different regimens).

Drugs used in oral infections

•The main oral infections:▫Candida.▫Oral herpes simplex.▫Herpes labialis.▫Non-specific stomatitis with/without

ulceration.▫Aphthous ulceration.

Drugs used in oral infection

•Candida:▫Nystatin drops.▫Miconazole gel.

•Oral herpes simplex:▫Aciclover suspension.

•Herpes labialis (cold sores):▫Aciclover 5% cream.▫Corticosteroid cream.

Drugs used in oral infections

•Non-specific stomatitis with/without ulceration:▫Dehydration if found should be corrected.▫Chlorhexidine mouthwashes.▫Hydrogen peroxide to cleanse ulcers.▫Benzydamine mouthwash.▫Choline salicylate (bonjela).

•Aphthous ulceration:▫Hydrocortisone pellets.

Gastroesophageal reflux disease (GERD).

•Symptoms:•Heartburn.•Regurgitation.•Hypersalivation.•Belching.

Goals of treatment.

•Reduce or eliminate symptoms.•Decrease the frequency and duration of

gastroesophageal reflux.•Promote healing of the injured mucosa.•Prevent the development of

complications.

Treatment of acid reflux / gastro esophageal reflux disease(GERD)

•Antiacids:▫Suspension or chewable tablet.▫Aluminium hydroxide and magnesium

hydroxide.▫Calcium carbonate.

•Combination of antiacids with alginates:▫Gaviscon (suspension, chewable tablet).

Treatment of reflux disease

•H2 Histamin receptor blockers:▫Ranitidine.▫Famotidine.▫Cimetidine.

•Mechanism of action.

•Side effects: headache, dizziness (occur only in small number of patients).

Treatment of reflux disease

•Proton pump inhibitors:•Lansoprazole.•Omeprazole.•Esomeprazole.•Pantoprazole.•Rebeprazole.

•Adverse effects: headache, nausea, diarrhea and rashes.

Drugs used to treat reflux disease•Metoclomperide.•Domperidone.

•Will discuss in antiemetic drugs.

Drugs used to treat peptic ulcers•Peptic ulcer are lesions of the lining

(mucosa) of the stomach (gastric ulcer), the duodenum (duodenal ulcer).

•Causes of peptic ulcer:▫Excessive secretion of HCl and pepsin.▫Breakdown of the protective mechanism of

the mucosa.▫A microorganism H.pylori.

Peptic ulcer disease PUD

Drugs used to treat peptic ulcers•Reduce acidity:•H2 receptor blockers.•Proton pump inhibitors (PPI).

•Ulcer protection:•Prostaglandins (PG) Misoprostol•Bismuth chelate, sucralfate.

Drugs used to treat peptic ulcers•Eradication of H.Pylori:

•PPI + clarithromycine 500mg+ amoxicillin 1g (with OR with out metronidazole).

•PPI+clarithromycin 500mg+ tetracycline.

Treatment of constipationlaxatives

•Bulk purges (laxatives):▫Bran.▫Methylcellulose.▫Ispaghula husk.

•Softening the feces in 1-3 days.

•Stool softeners:▫liquid paraffin/ 1-3 days.▫Docusate sodium/ 1-3 days.

Treatment of constipation/laxatives

•Osmotic purges:▫Saline purges ( magnesium sulfate)/ 6-12

hours▫Lactulose/ in 1-3 days.

•Stimulant purges:▫Senna.▫Bisacodyl.(oral 6-12 hours, rectal less than

1 hour)▫Sodium picosulfate.

Laxatives.•Glycerin supp

▫Exerts its effect by osmotic action in the rectum.▫The onset of action is usually less than 30

minutes.▫May occasionally cause rectal irritation.

•Phosphate enema:▫It works by pulling water from the body into the

bowel, which helps to soften the stool and cause a bowel movement.

Laxatives.•Costar oil:• Is metabolized in the GI tract to an active

compound, ricinoleic acid.

•Stimulates secretory processes and promotes intestinal motility, primarily in the small intestine.

•Castor oil usually results in a bowel movement within 1 to 3 hours of administration.

Antidiarrheal drugs

•Antimotility agents:▫Loperamide (capsule, tablet)

•Anticholenergic drugs.

•Kaolin-pectin.

Drugs used to treat IBS•Antispasmodics:

▫Hyoscyamine.▫Dicyclomine.

•Anxiolytic:

•Combination of antispasmodic with anxiolytic:▫Chlordiazepoxide + clidinium (LIBRAX).▫Chlordiazepoxide+propantheline (Medospas). ▫Diazepam +clidinium (Distedon).

Neurologic pathways involved in pathogenesis of nausea and vomiting

Emesis.• The three consecutive phases of emesis

include:• Nausea.

▫The imminent need to vomit, is associated with gastric stasis.

• Retching.▫ Is the labored movement of abdominal and

thoracic muscles before vomiting. • Vomiting.

▫ Is the forceful expulsion of gastric contents due to GI retroperistalsis.

Antiemetic drugs•Antihistamines:

▫Cyclizine.▫Cinnarizine.▫Promethazine.▫Meclizine.

Meclizine: used for the prevention of motion sikness also used in combination with B6 for nausea and vomiting in pregnency.

Cyclizine+ promethazine+ cinnarizine: prevent motion sikness.

Cinnarizine:prevent vertigo

Antiemetic drugs

•Dopamine antagonists:▫Chlorpromazine.▫Haloperidol.▫Domperidone.▫Metoclopramide.▫Domperidone and metoclopromide:

Used in chemotherapy-induced nausea and vomiting.

Postooperative and postoperation nausea and vomiting.

Side effects: sedating, restlessness, dirrhea.

Antiemetic agents•5-HT Antagonists:

▫Ondansetron. Used in chemotherapy-induced nausea and

vomiting. Postooperative and postoperation nausea and

vomiting.•Miscellaneous:

▫Betahistine. Vertigo.

▫Dexamethasone. Chemotherautic induced nausea and vomiting.

Inflammatory bowel disease.• Is any inflammation of the bowel and includes

crohn’s disease and ulcerative colitis.

• These are chronic autoimmune disease.

• Crohn’s disease can affect any part of the GIT, but commonly affect small bowel and colorectum.

• Ulcerative colitis is confined to the colon and rectum.

Drugs used in IBD

•Cortecosteroids.•Aminosalicylates.•Immunosupressants.

Corticosteroids.

•Prednisolone :▫Is the most common one used.▫Given orally until disease remits.▫Enemas may be used.

•Budenoside:▫Subject to first pass effect.▫Available as controlled-release oral

formulations.

Aminosalicylates.

•Drugs that contain 5-aminosalicylic acid.•Sulfasalazine, olsalazine called azo

compounds because 5-ASA bound by azo N≡N to inert compound or to other 5-ASA molecule.

•The azo structure reduces absorption of the parent drug from small intestine.

•Mesalamine compounds 5-ASA packaged in different ways to deliver in different segments of S.I or large bowel.

Aminosalicylates.

•Mesalamine compounds:•Mesalazine (pentasa), available as oral

tablet and rectal supp.•Asacol is delay-release preperation of

mesalazine.•These group of drugs used to keep

patient in remission.

Immunosupressant.

•Reduce the activity of the immune system.•Drugs in this group:•Azathioprine (Imuran) oral/ I.V

▫Monitor blood count regularly.•Methotrexate. Oral, IM, IV.

•Used to induce and maintain remission in patients.

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