how drugs work

Question 1

what 4 ways can drugs have an action?

Answer 1

either through acting on receptors, enzymes, ion channels or transporter proteins

Question 2

how do drug receptor interactions occur?

Answer 2

drugs bind to receptors and either activate them, or deactivate them.

when activated the receptors either produce a direct effect or they act through transduction mechanisms

Question 3

how do drug transporter mechanisms work?

Answer 3

drug will either be successfully transported by the transporter protein, or it will bind and inhibit or regulate passage of molecules.

false substrate binding to the transporter can lead to a build up of incorrect compound.

Question 4

how do drugs influence ion channels?

Answer 4

drugs can bind to the ion channel and block passage of ions.

or the drug can bind to the channel and regulate it. It can increase passage of ions or decrease them.

Question 5

how do drugs influence enzyme activity?

Answer 5

a prodrug will enter the enzyme and the correct constituents leave.

a false substrate in the enzyme will lead to a build up of incorrect metabolite.

an inhibitor will bind to the enzyme and prevent activity.

Question 6

how may drugs be distributed in the body

Answer 6

binding to plasma proteins leading to a bound drug reservoir

diffused into tissues

• speed relies on the thickness of vessel walls
• blood-flow to area
• active secretion of the drug

also active lipid binding leading to slow and long release
- good for general anaesthetics like halothane