2.2 Pharmacodynamics Flashcards
How do most drugs work?
By interacting with endogenous proteins
Name some places where drugs work
Cell surface receptors, nuclear receptors, enzyme inhibitors, ion channel blockers, Transport inhibitors
What shapes are michaelis menten curve?
Rectangular hyperbola
Drug response proportional to drug concentration
Describe drug selectivity
The more the selective a drug is for its
target, the less chance that it will interact
with different targets and have less
undesirable side effects
Describe drug specificity
Targeting drugs against specific receptor
subtypes often allows drugs to be targeted
against specific organ
What does affinity define?
The tendency of a drug to bind to a specific receptor type
Define efficacy
Ability of a drug to produce a response as a result of the receptors being occupied
What does efficacy describe?
The maximum effect of a drug
Describe potency
Dose required to produce the desired biological response
Describes the difference doses of two drugs required to exact the same effect
What is the equation for therapeutic index?
Therapeutic index = EC50 adverse effect / EC50 desired effect
Therapeutic index = toxic dose / effective dose
What is the therapeutic window?
The range of doses that can effectively treat a condition while still remaining safe
What is the therapeutic window between?
The lowest dose that has a positive effect and the highest dose before the negative effects outweighs the positive effects
Give some examples of drugs with a narrow therapeutic window
Warfarin, aminophylline, gigoxin and aminoglycoside antibiotics
What do fatty meals do to gastric transit time?
Slow it down
What is the principle behind drinking alcohol following a fatty meal?
Gpfatty meals slow down gastric transmpit time
Alcohol takes longer to get through stomach
Most alcohol absorbed in duodenum so prolong time to get there giving a constant drip effect
What is the problem with taking iron and tetracycline?
Bind together to form a chelate
Drug isn’t absorbed