GIT drugs Flashcards
DF , invasive factors ,pharmacological therapy of peptic ulcer
-DF: ulceration of the duodenum or stomach duo to imbalance between local invasive force and protective force
-invasive factors :
1-stress lead to increase HCL
2-Drugs : Such as NSAIDs , corticosteroids, morphine methylexens
3- infection of Helicobacter pylori
—pharmacological therapy of peptic ulcer :
1-drugs that decrease HCL secretion:
1.1 Selective M1 blockers > Pirenzepine
1.2 H2 blockers > Ranitidine , Famotidine
1.3 Proton pump inhibitor > Omeprazole,Pantoprazole
explain the M1 blocker drug for Peptic ulcer
-Drug: Pirenzepine Tab
-mechanism of action : selectively block M1 receptor which lead to decrease the basal HCL secretion, indirectly inhibit H2 by inhibition Of the signalling from M1 to H2
-adverse effect : high dose lead to atropin like action , dry mouth, bullred vision , tachycardia
-uses : they are week inhibitors of HCL secretion
explain H2 blockers
-Drug: Ranitidine , Famotidine Tab
-mechanism of action :they are competitive antagonist of histamine 2 at the parietal cells , which suppress the normal and meal-stimulted Secretion of HCL
-adverse effect :
1-reversible hepatotoxic
2-microsomal inducer
3-CNS symptoms, headache, slurred speach
-uses : duodenal and gastric ulcer
, stress ulcer
explain the proton pump
-Drug : Omeprazole , Pantoprazole
-mechanism: At ph less then 5 couventally with SH groups of hydrogen potassium atpese and inactive hydrogen potassium atpese irreversibly , inhibit of HCL occurs with 1 hour maximum 2
NB! omeprazole may inhibit CYP2c19 drug interaction
-adverse effect :
1-dahrria
2-decrease B12 absorption after 12 week
3-decrease or inhibit acidity of stomach which lead to change PKA or bioavailability of other drugs
-Uses : peptic ulcer
explain the Previntation or healing drugs of peptic ulcer
-Drugs : bismuthi trikalii dicitras tab
-mechanism: pertipate in ph less then 5 to form a glycoprotein-bi complex which coat ulcer and act as barrier to acid , and increase secretion of mucosa and bicarbonate through stimulation of PGe1 and detaches of hilcobacter and kills them directly
-side effect :
1-dhirria
2-blackening of stool and tongue
-uses : in combination with antibiotics and proton pump inhibitor for treatment of hilicobacter pylori infection
explain the PGs Analogies
-Drug : Misoprostol > synthetic PgE1
-mechanism: reduce acid secretion less then H2 blockers, short duration , and increase secretion of mucosa and bicarbonate and microcirculation increase
-side effect :
1-Diarrhoea
2-abdominal cramps
-uses : prevention and treatment of NSAIDs gastric injury 
explain Antiemetic , DF , groups of Drugs
-DF: Vomating is characterised by events culminating in the forceful explosion of gastric contents through the mouth
—groups of drugs :
1-H1 blockers
2- 5-HT3 blockers
3-Dopamine blocker
4-NK-1 receptor antagonist
explain the Antiemetic drugs H1 blocker
-Drug: Diphenhydramine
-mechanism: its block H1 and also M1 receptor in vestbiolcerbral pathway in CTZ , which lead to Sedative action
-Side effect : sedation , atropin like action , hypotension
-uses : vomiting duo to motion sickness , and pregnancy
explain the 5-HT3 receptor blocker
-Drug: Ondansetron
-mechanism: its blocks 5-HT3 receptor in CNS ( CTZ ) and peripherally on GI vagal afferent
-Uses : Vomating duo. to cancer chemotherapy or radio therapy, post operative
explain the Dopamine blockers
- Drugs :
1-Metoclopramide > acts centrally and peripherally
2-Domperidone > acts peripherally only bcs doesn’t pass BBB
-mechanism: they non selective but the are more potent on D2 , they block D2 receptor in CTZ and Gi
-side effect: sedation, extrapyramidal manifestations
-uses : vomiting duo to drug or fever
explain the NK-1 receptor blockers
-drug : Aprepitant > Caps
-mechanism: substance-P induce vomiting through stimulation of NK-1 receptor, So aprepitant blocks the NK-1 Receptor
-side effect : diahrroe and fatigue
-uses : in combination with 5-HT3 blocker to treat vomiting duo to chemotherapy or post operative
