Module 7 Flashcards
sources of drugs
- plants
- animals
- micro organisms
where is morphine derived from
poppies
where was adrenaline originally sourced from
adrenal gland of monkeys, sheep and cows (now artificially replicated )
generic name
refers to the group or family that a drug belongs to
chemical name
a description of a drugs composition
Approved name
usually derived from chemical name and approved by local drug authority
propriety name
brand name
oral/ enteral route
orally taken drugs e.g. capsules
parental route
administration of a drug via any route other than the mouth or digestive tract e.g. injection
list the factors that influence the amount of drug that interacts with its target
- Absorption
- Distribution
- Metabolisation
- Excretion
pharmacokinetics
the study of how the body effects the drug
Drug Absorption
process of an unchanged drug moves from the site of administration into the systemic circulation (e.g. when taken orally)
Factors affecting Drug Absorption
- formulation of drug
- route of administration
- tissue surface area and thickness
- blood supply at the site of administration
- solubility of a drug
Drug Distribution
the process of reversible transfer of a drug between 1 location and another
Factors affecting drug distribution
- health of cardiovascular system
- degree of blood flow
- permeability of capillaries
- lipid or water solubility of the drug
- if drugs can bind to and stored in tissues and released slowly over time
- barriers such as: blood brain barriers, placental barriers
Drug Metabolism
the chemical modification of a drug and usually carried out by enzymes ( and results in more water soluble compound)
Drug Metabolism - Functionalisation reaction
chemical changes that produce a more water soluble compound
Drug metabolism - Conjugation reaction
joining the drug with another substance to produce a more water soluble compound
what is the primary site of metabolism
liver
- but can also occur in the kidneys, lungs, and intestinal mucosa
Factors affecting drug metabolism
- genetics
- environmental factors
- age and gender
- disease states e.g. slow cardiovascular system
hepatic first metabolism
drugs that are administered orally first pass through the stomach and small intestine are absorbed into the hepatic portal vein for transport to the liver
(small amount of drug may be absorbed in gastrointestinal tract)
first pass metabolism
most drugs that each the liver undergo metabolism before they reach systemic circulation
bioavailability
the remaining amount of drug can exert a pharmacological effect and reaches systemic circulation
how much bioavailability will a drug administered intravascularly have ?
100% as it avoids first pass metabolism
Drug Excretion
the irreversible loss of drug from the body
usually excreted via kidneys in the urine
Drug Elimination
the irreversible loss of the drug from the plasma (usually occurs in the liver due to metabolism)
what is the process of excretion dependent upon ?
urinary pH ranging from - 4.6 - 8.2
renal and cardiovascular function
what is a dosage regimen
- amount of drug administered
- often the drug is administered
factors that affect dosage regimen
- age
- gender
- health
- cardiovascular, liver and kidney function
therapeutic range
the range of drug concentrations that have a high probability of producing the desired therapeutic effect and low probability of toxic effects and lies between 2 ranges:
- minimum effective concentration
- maximum effective concentration
minimum effective concentration
minimum amount of drug required for pharmacological effect
maximum effective concentration
minimum amount of drug that causes a toxic effect
drug half life
the time taken for the drug concentration to be reduced by 50% from its maximum concentration
what does the drug half life determine
- duration of action of single dose of drug
- how often to administer to keep within therapeutic range
what is term used for the maximum drug concentration
T maximum
Pharmacodynamics
the study of how the drug effects the body
and the mode of drug action
what does the mode of drug action depend on
- proteins (primary target) (carrier proteins, ion channels, enzymes, receptors)
- DNA
Drugs and carrier Proteins
drugs can alter the function of carrier proteins involved in facilitated diffusion as drugs bind to and prevent the carrier protein from moving molecules into the cell
drugs and ion channels
- binding to the channel causing the channel to open or close
- blocking the channel
competitive inhibitors
drug binds to the enzymes active site to slow/inhibit activity
non competitive inhibitors
drug binds to the enzyme, changing the shape - preventing the substrate from binding = enzyme destroyed
agonist receptors
initiates or enhances the normal response
antagonist receptor
blocks the normal response
drug hypersensitivity
the body’s immune system shows exaggerate response to drug received as foreign substance
Adverse drug reaction
an unintended effect of a drug
poly pharmacy
taking multiple drugs together
drug - drug interaction
occurs when the pharmacological effect of one drug is altered by another
drug containdications
are the conditions that determine when a drug should not be taken
