Choose the word or phrase from the list below that best completes this sentence.
Pharmacokinetics can be described as ________________________
how the drug elicits it's effect in the body.
how the body handles a drug.
the composition of a drug.
the way in which a drug should be stored.
Drugs may act locally or systemically. Systemically means that the drug must enter ___________________ in order to be delivered to its site of action.
the brain
the circulation
the lymph nodes
the heart
Which equation can you use to calculate the amount of a drug that reaches the systemic circulation?
F x dose
F/dose
F - dose
F + (2 x dose)
Drugs administered as an IV injection have a bioavailability of _________.
100
10
1.0
0.1
What words make up the acronym ADME?
Administration
Absorption
Distribution
Dissolving
Making
Metabolism
Exit
Excretion
Generally in absorption, drugs move from an area of high concentration to a low concentration via ______________
osmosis.
active transport.
passive diffusion.
When drugs are being absorbed from an area of their low concentration to a higher concentration, they move by _____________
Cell membranes are composed of a double layer of ____________________
proteins.
sugars.
phospholipids.
ions.
Water soluble drugs pass cell membranes easier than lipid soluble drugs.
The more _______________ a drug, the easier it is for the drug to be absorbed from the small intestine into the circulation.
lipid soluble
water soluble
Un-ionised drugs are lipid soluble.
What does un-ionised mean?
The drug carries no charge.
The drug is negatively charged.
The drug is positively charged.
The molecule contains two opposing charges.
The small intestine has a large surface area due to it's large number of __________.
villi
cillia
hairs
cells
The larger the surface area for drug absorption, the _______ the absorption.
slower
quicker
Where does most drug absorption take place?
Stomach
Small Intestine
Large Intestine
Colon
The presence of food after a meal will slow gastric emptying.
Sometimes drugs are prescribed to be taken with food. Why might this be?
To lessen the side effects of a drug by preventing large concentrations from entering systemic circulation at the same time, ensuring a more gradual absorption due to gastric emptying.
To mask the bad taste of a drug that is taken orally.
To prevent local side effects, like irritation of the stomach lining, caused by drugs like NSAIDs.
Some drugs are absorbed from the small intestine into the _____________ and are transported directly into the liver.
renal portal vein
cranial portal vein
hepatic portal vein
What is the name of the process by which a drug is fully or partially metabolised by the liver, before entering the systemic circulation?
First pass metabolism
Liver/drug degradation
First past metabolism
Hypomotility of the GI tract may result in lower concentrations of drug entering the circulation.
Blood flow affects absorption.
A drug must reach it's site of action in ______________, in order to exert it's effect.
an adequate concentration
a membrane bound vesicle
a salt solution
Blood flow affects distribution.
Blood flow affects distribution. Organs that have high perfusion, e.g. heart, therefore receive drugs slowly.
Only ________ drug can cross plasma membranes and therefore exert an effect.
free
plasma protein bound
albumin bound