Dms Pharmacology

Front 1

Define bioavailability

Back 1

is the most important parameter for the clinician. This is the amount of drug that actually reaches the target site in a pharmacologically active and bioavailable form. Bioavailability is affected by all these parameters, and understanding them helps us to assess dose, form, route of administration, etc.

Front 2

What are the factors the affect drug distribution and excretion?

Back 2

In plasma drugs exist in equilibrium between bound and free drug. Many drugs almost entirely bound to albumin(~1% or less the rest is bound up by plasma proteins), only the drug that is not bound will be active because it leaves plasma. diff compartments compete for drug, it can be metabolized excreted, the site of action which is the bioavailable fraction of the drug.

Front 3

What happens if you increase the amount of unbound drug?

Back 3

You effectively increase the dose of the drug

Front 4

What factors influence the passage of drugs across membranes?

Back 4

1. physio-chemical properties of drugs
2. pH of compartment - the degree of ionization will affect the partition coefficient and the extent of the diffusion
3.

Front 5

Define partition coefficient

Back 5

Put a drug into a 50/50 octanol water solution. If it partitions mostly into the octanol it means it is very lipid loving, and water the opposite.

Front 6

What is the form of the drug that can cross membranes?

Back 6

The UNionized form

Front 7

Define pKa

Back 7

the point at which half of the drug is in the ionized form and half is in the unionized form

Front 8

Are weak bases absorbed in the stomach?

Back 8

No

If someone ODs on a weak base you can measure the amount of drug in the stomach and then you can estimate how much drug they took regardless of the route of administration.

Front 9

Where do you sample to determine the amount of an acidic drug taken in an OD?

Back 9

in the blood, regardless of the route of administration