pharmacology of drugs affecting git
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Pharmacology of drugs affecting GIT. Peptic Ulcer Disease. Imbalance between mucosal defensive factors and aggressive factors Major defensive – mucus and bicarbonate Major aggressive – gastric acid, H. pylori, nonsteroidal anti-inflammatory drugs, pepsin. Defensive factors. - PowerPoint PPT PresentationTRANSCRIPT
Pharmacology of drugs affecting GIT
Peptic Ulcer Disease Imbalance between mucosal defensive
factors and aggressive factors Major defensive – mucus and bicarbonate Major aggressive – gastric acid, H. pylori,
nonsteroidal anti-inflammatory drugs, pepsin
Defensive factors Prevent the stomach and duodenum from being
harmed (self-digestion). Mucus – continually secreted, protective effect Bicarb – secreted from endothelial cells,
neutralized hydrogen ions Blood flow – good blood flow helps to maintain
mucosal integrity Prostaglandins – stimulate secretion of bicarb and
mucus and help promote blood flow, suppress secretion of gastric acid
Aggressive factors Helicobacter pylori – gram negative
bacteria, can live in stomach and duodenum
May breakdown mucus layer, inflammatory response to presence of the bacteria may breakdown defenses, also produces urease – forms CO2 and ammonia which are toxic to mucosa
PepsinSmoking
NSAIDS – inhibit the production of prostaglandins
Decrease blood flow, decrease mucus production and bicarb synthesis, promote gastric acid secretion
Gastric Acid – also needs to be present for ulcer to form – activates pepsin and injures mucosa
Nondrug therapy Diet – change in eating pattern, 5-6 small
meals a day Smoking cessation, NSAID and ASA
should be avoided whenever possible, avoid alcohol
Antibacterial drugs Combinations must be used Bismuth – disrupts cell wall of H. pylori,
pepto-bismol Clarithromycin – inhibits protein synthesis Amoxicillin – disrupts cell wall, good
when given with omeprazole Tetracyclin – inhibits protein synthesis Metronidazole – resistance,
Histamine 2-receptor antagonists Suppress secretion of gastric acid (activation of
H2 receptors promotes secretion of gastric acid) Cimetidine - first available, oral, IV, IM May take up to twelve weeks for ulcer to be
healed Therapeutic uses – ulcers, GERD, Zollinger-
ellison syndrome, aspiration pneumonitis, heartburn, indigestion
Proton Pump Inhibitors Suppress secretion of gastric acid Omeprazole – prilosec – prodrug that
converts to active form in parietal cells of stomach – inhibits enzyme that generates gastric acid
Ulcers, GERD, Zollinger-Ellison syndrome May contribute to development of gastric
tumors?
Sucralfate Creates a protective barrier against acid
and pepsin Form sticky gel that coats ulcer portion Given every 6 hours Very few side effects – minimal systemic
absorption
misoprostol Cytotec – prevention of gastric ulcers
caused by long-term NSAID therapy Replacement for endogenous
prostaglandins
Antacids Peptic ulcers and GERD Neutralize acid Dosing – 7 times per day
AlmagelCombined drug which contains gel of aluminum hydroxide, magnesium oxide and D-sorbit
170 ml bottles
Schemes of combined treatment of gastric ulcer
De-nol + amoxycillin
De-nol + metronidazole
Omeprazole + amoxycillin + clarythromycin
De-nol + clarythromycin + metronidazole
De-nol + controlok + amoxycilin + clarythromycin
Laxatives Laxative effect – production of a soft
formed stool over a period of 1 or more days
Catharsis – prompt, fluid evacuation of the bowel, more intense
Function of the colon – water and electrolyte absorption
Bowel evacuation – individual Dietary fiber
Indications for laxative use Pain associated with bowel movements To decrease amount of strain under certain
conditions Evacuate bowel prior to procedures or
examinations Remove poisons To relieve constipation caused by
pregnancy or drugs
Just because laxatives are available without a prescription doesn't mean that they're without risk.
Warning: Use of stimulant laxatives over a long period may lead to dependence and might permanently damage intestine and colon
Classifications I – osmotic (high doses) II – osmotic (low doses), stimulant except
castor oil – most frequently abused III – bulk-forming, surfactant
Bulk-forming Identical to fiber – soften fecal mass,
increasing bulk Temporary treatment of constipation,
preferred for patients with inflammatory bowel diseases
May help with diarrhea
Adverse reactions Not absorbed – no systemic effects Must take with sufficient water Intestinal, esophageal obstruction Metamucil, citrucel
Surfactant laxatives Bisacodyl, castor oil Stimulate intestinal motility Increase water and electrolytes in intestinal
lumen Produce stool within 6-12 hours
Bisakodil
Guttalax
Miscellaneous laxatives Mineral oil Lactulose Glycerin suppository Polyethylene glycol-electrolyte solutions
Laxative abuse Most common cause of constipation Teaching
Choleretics of plant origin
Stigma of cornStigma of corn
Common immortelleCommon immortelle
Dog-roseDog-rose
Tocopherole acetate (Tocopheroli acetas)Vitamin E is produced in many forms: 5 %, 10 % and 30 % oil solution in 10, 20 and 50 ml bottles; elastic
capsules with 0,1 and 0,2 ml of 50 % solution in oil; ampoules with 1 ml of 5 %, 10 % and 30 % oil solutions.
Carsil Legalon
Mechanism of action of legalon
Essentiale Is produced in 5 ml ampoules and in capsules
Lipostabil
Pancreatin (Panсreatinum) Is produced in 0,25 g and 0,5 g dragee (tablets).
Panzynorm forte
Festal, Enzistal, Mezym-forte
No-spa, nicospan
Baralgin
Bil-berries St. John’s wort
Pepper mint Chamomile