Pharmacology Flashcards
What are the 4 types of molecular targets?
- Transporter proteins
- Ion channels
- Enzymes
- Receptors
What are the 4 types of receptors?
- Ligand gated
- G-protein coupled
- Catalytic
- Nuclear
How do agonist drugs work?
They produce a functional response in the same way as an endogenous agonist.
What do antagonist drugs do?
They block the binding sites.
What does EC50 refer to?
Potency - the drug concentration at which the drug produces 50% of the maximal response.
Optimal therapeutic effect is seen between — to — % drug concentration.
20 to 80
What 5 factors effect absorption?
Absorption surface Blood flow Solubility of the drug Ionisation Formulation
What is the approximate pH of the stomach?
2
Why is the duodenum more alkaline than the stomach?
The pancreas secretes bicarbonate ions into the duodenum.
Acids in a basic environment become ——- and won’t move across ——— easily.
ionised
membranes
(and vice versa)
Most absorption occurs in the ——–
intestines.
What is the first pass effect?
Percentage of hepatic excretion of an oral drug prior to it reaching the systemic circulation.
Define drug distribution.
Irreversible transfer of a drug from one location to another.
What 6 factors effect drug distribution?
Blood flow Cardiac output Organ/ tissue perfusion Lipid solubility Presence of drug transporters Plasma protein binding
Other than protein-binding, what tissues can drugs bind to?
Bone matrix and adipose tissue.
What 4 mechanisms are involved in drug clearance?
Kidney excretion
Biliary/ faecal excretion
Hepatic metabolism
Pulmonary excretion
What are the two main ways that drugs are metabolised?
Functionalisation and conjugation
What is functionalisation?
One of the ways drugs are metabolised.
Enzymes, usually of the P450 family, are added to the drug which makes them more water soluble.
What is conjugation?
One of the ways a drug is metabolised.
A chemical group present in the drug is added to the polar group of an endogenous substance.
What is the role of genetics in metabolism?
Genes are required for enzyme production to metabolise drugs.
What are the 3 ways in which the kidneys eliminate drugs?
Filtration
Reabsorption
Secretion
What is enzyme induction, and why is it significant?
Increased expression of enzyme protein. (ie., one drug can increase production of another enzyme).
Can result in increased metabolism of another drug.
What is enzyme inhibition, and why is it significant?
Two drugs competing for the same enzyme.
Results in decreased metabolism of at least one of them.
What is hepatic uptake?
Drug has to enter hepatocytes to undergo metabolism.
