pc term 1 Flashcards
(51 cards)
the 2 categories of antiulcer drugs are
1. reducing acid in stomach
2. mucosal protective agents
what are 3 ways to reduce acid in stomach?
- antacids to neutralise gastric acid
- H2 blockers to reduce acid secretion
- PPIs to irreversibly inhibit gastric acid secretion
the 2 categories of antiulcer drugs are
1. reducing acid in stomach
2. mucosal protective agents
what are the 3 mucosal protective agents?
- sucralfate forms viscous gel that acts a protective barrier in stomach
- bismuth compounds that form a protective layer to coat ulcer beds + anti microbial activity against H. Pylori
- misoprostol which is a synthetic PGE1 to promote bicarb & mucus secretion, enhance mucosal blood flow, inhib gastric acid secretion
what is in triple therapy for H. pylori infection?
PPI
metronidazole (antibiotic)
clarithromycin or amoxicilin (antibiotic)
what is in quadruple therapy for H. pylori infection?
PPI metronidazole clarithromycin amoxicilin (antibiotics)
or
PPI bismuth-subcitrate metronidazole tetracycline
why is H pylori a toxigg bitch
it enters stomach and attach to epithelial layer -> has enzymes that can convert urea into NH3 to neutralise gastric acid -> H pylori just hang ard the stomach and cause a shit ton of infection & mucosal cell death
what is the mechanism of omeprazole
- a PPI
- targets parietal cells, inhibs H+ K+ ATPase
- in prodrug form -> absorbed by parietal cells to form covalent disulphide bond w H+ K+ ATPase
- irreversibly inhibit gastric acid secretion
- slight antimicrobial activity against H. pylori
- PPIs need to be given on empty stomach
what is therapeutic index and how is it measured
TI = TD50/ED50
measures safety of drug
what is efficacy
efficacy = likelihood of activating effector and eliciting a response
higher efficacy = higher E max
what is efficacy of
a) full agonist
b) partial agoist
c) antagonist
a) a = 1
b) 0 < a < 1
c) a = 0 since antagonist do not produce a direct response
what is E max
emax = maximum response of a system
what is potency
potency = dose required to produce a given degree of response
lower dose = higher potency
what is EC50
EC50 = drug dose required to produce 50% of the fx
what are the 3 types of antagonism
- chemcial antagonism in which antagonist itself cancels out the fx of active drug
- pharmacological antagonism in which antagonist binds to receptor to prevent active drug from forming DRC
- physiological antagonism in which antagonist causes and opposing fx to active drug via different mechanism
how will [drug] - dose curve shift when non competitive antagonist is added
curve shift down
Emax decreases
EC50 remains same
how will [drug] - dose curve shift when competitive agonist is added
curve shift right
Emax same
EC50 increases
How will [drug] - dose curve shift when agonist is added
curve shift left
emax same
EC50 decreases
steady state of drug concentration is received after how many t1/2?
after 5 t1/2
MOA of antihistamines?
competitive H1 receptor antagonist
what does alpha 1 receptor control
dilate pupils (midriasis) increase aq humour secretion increase glycogenolysis piss less (alpha in general) vasocon for viscera bv, decrease GIT motility and secretion
what does alpha 2 receptor control
reduce salivary production
(alpha in general) vasocon for viscera bv, decrease GIT motility and secretion
what does beta 1 receptor control
increase HR and contractility
increase renin release in kidney
(beta in general) increase aq humour secretion
what does beta 2 receptor control
bronchodilation increase glycogenolysis decrease GIT motility and secretion vasodilation of skeletal mm bv (beta in general) increase aq humour secretion
what does beta 3 receptor control
increase lipolysis
piss less
(beta in general) increase aq humour secretion
what does M1 receptor control
increase stomach secretion
