General Pharmacology Flashcards
Calculation for oral bioavailability
Plasma conc / dose given
Factors affecting oral bioavailability
Lipophilicity, Molecule size, First pass metabolism
Calculation for distribution
Dose given / plasma conc
Compartments the drug is in with a Vd < 0.2
Plasma
Compartments the drug is in with a Vd between 0.2 and 0.7
ECF
Compartments the drug is in with a Vd > 0.7
Whole body (Fat)
Factors affecting volume of distribution
Lipid solubility, DDIs, Protein binding, Diseases
Measure of elimination
Half-life
Calculation for half life
0.693 x Vd / Clearance
Define first order kinetics
Elimination is proportional to dose
Define zero order kinetics
Elimination constant over time
Number of half lives to reach steady state
4-5
Calculation for loading dose
Vd x Desired conc
Define selectivity
Drugs ability to bind to a receptor
Define specificity
Drugs ability to cause a response in a receptor
Define affinity
How readily a drug binds to a receptor
Measure of affinity
Kd
Define Kd
Conc at which 50% of receptors are occupied
Define efficacy
Degree of response from a receptor generated by a drug
Define potency
Dose required to generate a response
Measure of potency
EC50
Define EC50
Conc at which a 50% response is generated
Types of ADRs
On target and off target
Define on target ADRs
Greater than desired effect at target site
