Pharmacology & ADRs
DRUGS
TERM DEFINITION
Agonist Activates receptor by binding e.g. salbutamol
Antagonist Binds to prevent something else binding e.g. antihistamine/bisoprolol
Partial Antagonist Part activation of a physiological response e.g. buprenorphine – also
antagonist to other opioids
A inity Extent of binding of drug to the receptor
E icacy Ability of the drug once bound to activate receptor (i.e. cause an
e ect)
Drug moving from site of administration into the bloodstream
Absorption (In PO administration – absorbed through the gut wall)
Can be a ected by poor blood flow at site, surface area, contact time, drug solubility and
stability
Distribution Distribution of the drug around the body once absorbed into
circulation (Blood Plasma, Intracellular, Interstitiual fluid, Fat, other bodily fluids)
(Factors that a ect distribution ⟩ Blood flow, plasma protein binding)
Metabolism Changing of the chemical structure of the drug by the body to make it
easier to excrete (Liver is the main organ of drug metabolism)
Metabolite – Product of metabolism (Prodrugs need to be metabolised to
become active e.g. codeine – metabolised to become morphine)
Excretion Removal of drug and/or metabolites from the body (Urine, sweat, expired
air, breast milk, faecal)
Pharmacodynamics E ect the drug has on the body
Pharmacokinetics E ect the body has on the drug
Half-life Time it takes for plasma concentration od the drug to fall to half its
original value
Bioavailability Proportion of the drug that reaches systemic circulation
(IV = 100%, PO 10-80%) (Some drugs cannot be taken orally as they will be destroyed by the
acid in the gut e.g. Insulin)
ADVERSE DRUG REACTIONS
TERM DEFINITION
ADR Response to a medicinal product which is noxious or unintended
Mechanism of ADR through elimination, pharmacodynamic, metabolism
A Acceptable / Predictable – dose related, not usually severe
Types B Bizarre / Unpredictable – not dose related, can be severe / life
threatening
C, D, E Chronic, Delayed, End of Use
Important Factors in ADRs
DoTS Do Dose; below, in or above therapeutic range
T Time; of onset
S Susceptibility; factors e.g. age, gender, physiological state, disease
Reporting ADRs MHRA Yellow Card Scheme
(ALL drugs with black triangle) (All serious suspected ADRs)(Children; Age >65; Vaccines)
DRUGS
TERM DEFINITION
Agonist Activates receptor by binding e.g. salbutamol
Antagonist Binds to prevent something else binding e.g. antihistamine/bisoprolol
Partial Antagonist Part activation of a physiological response e.g. buprenorphine – also
antagonist to other opioids
A inity Extent of binding of drug to the receptor
E icacy Ability of the drug once bound to activate receptor (i.e. cause an
e ect)
Drug moving from site of administration into the bloodstream
Absorption (In PO administration – absorbed through the gut wall)
Can be a ected by poor blood flow at site, surface area, contact time, drug solubility and
stability
Distribution Distribution of the drug around the body once absorbed into
circulation (Blood Plasma, Intracellular, Interstitiual fluid, Fat, other bodily fluids)
(Factors that a ect distribution ⟩ Blood flow, plasma protein binding)
Metabolism Changing of the chemical structure of the drug by the body to make it
easier to excrete (Liver is the main organ of drug metabolism)
Metabolite – Product of metabolism (Prodrugs need to be metabolised to
become active e.g. codeine – metabolised to become morphine)
Excretion Removal of drug and/or metabolites from the body (Urine, sweat, expired
air, breast milk, faecal)
Pharmacodynamics E ect the drug has on the body
Pharmacokinetics E ect the body has on the drug
Half-life Time it takes for plasma concentration od the drug to fall to half its
original value
Bioavailability Proportion of the drug that reaches systemic circulation
(IV = 100%, PO 10-80%) (Some drugs cannot be taken orally as they will be destroyed by the
acid in the gut e.g. Insulin)
ADVERSE DRUG REACTIONS
TERM DEFINITION
ADR Response to a medicinal product which is noxious or unintended
Mechanism of ADR through elimination, pharmacodynamic, metabolism
A Acceptable / Predictable – dose related, not usually severe
Types B Bizarre / Unpredictable – not dose related, can be severe / life
threatening
C, D, E Chronic, Delayed, End of Use
Important Factors in ADRs
DoTS Do Dose; below, in or above therapeutic range
T Time; of onset
S Susceptibility; factors e.g. age, gender, physiological state, disease
Reporting ADRs MHRA Yellow Card Scheme
(ALL drugs with black triangle) (All serious suspected ADRs)(Children; Age >65; Vaccines)
