Pharmacology Flashcards
Formula for therapeutic index
TI = median lethal dose /median effective dose
Formula for dissociation constant
Kd = K2 /K1
Kd = [R][D]/ [RD]
Formula for proportion of receptors occupied by drug
p = [D]/ (kd + [D])
Surmountable antagonism?
Competitive reversible
Insurmountable antagonism?
Competitive irreversible OR noncompetitive antagonism
What is the partition coefficient?
p = oil/water
higher p = higher oil content
Non ionized molecules absorption
Non ionized molecules = easy absorption; more lipophilic
Ionized molecules absorption
Ionized molecules = tough absorption; less hypophillic
acids ionization increase
pH increase = increase in ionization of acids
Acids are more absorbed in low pH environments
bases ionization increase
pH decrease = increase in ionization of bases
Bases are more absorbed in high pH environments
% bound drug formula?
% bound = [bound drug] /[bound drug]+ [free drug]
warfarin and relevance to pharmacokinetics
= anticoagulant
normally bound 98%, but when patient also takes aspiring, becomes bound 96% (drugs compete for the same proteins) and effective dose is doubled
pharmacokinetics
what body does to drug
pharmacodynamics
what drug does to body
Metabolism is responsible for making drugs more ________ to make them easier to eliminate
hydrophilic
