PHARM - Pharmacodynamics and Pharmacokinetics – Why Should You Care? - Week 2 Flashcards
Describe the four structures that are concerned with pharmacodynamics, and an appropriate anagram.
Receptor Ion channels Carriers Enzymes RICE
Describe the four components of pharmacokinetics, and an appropriate anagram.
Absorption Distribution Metabolism Elimination ADME (also MEAD)
What kind of drugs can be used for the following (classification based on target action): Receptor (3) Ion channel (2) Carrier/transporter (1) Enzyme (2)
Receptor
-agonist, antagonist, partial agonist
Ion channel
-opener, blocker
Carrier/transporter
-inhibitor
Enzyme
-inhibitor, substrate
Name 8 routes of administration.
Oral Sublingual Buccal Topical Inhalant Transdermal Subdermal Parenteral
Name 3 parenteral routes of administration.
Subcutaneous
Intramuscular
Intravenous
Define pharmacogenetics.
Study of genetic influences on response to drugs.
Define pharmacogenomics.
Study describing the use of genetic information to guide the choice of drug therapy on an individual basis.
Define polymorphism.
They are variations at a locus within a genome that persists in a population through several generations (like blue eye colour or lactose tolerance).
How do polymorphisms arise initially. How do they stabilise/die out?
From mutations. They stabilise if they are advantageous or non-functional, or die out in subsequent generations if disadvantageous.
Define a single nucleotide polymorphism. What is the typical cause?
A polymorphism that arises due to a mutation to a single base pair. Usually is a substitution of a C for a T.
Give 3 ways genes can influence drug response. Are these solely due to genes, or are there other factors?
- The same drug at the same dose works well for some people, but not others.
- Some people need higher or lower doses of the same drug.
- Some people have adverse effects while others dont.
Many factors contribute to these such as age, smoking, and health status, but genetics is an important factor.
Define phase I enzymes, and what they are responsible for. What significantly affects blood levels and drug responses?
Phase I enzymes - CYP450
They biotransform over 75% of prescription drugs.
Polymorphisms significantly affect blood levels and drug responses.
Describe what CYP2D6 enzymes do.
They metabolise up to 25% of all clinically used drugs, and displays the largest variability in metabolic capacity.
Name the four metabolic phenotypes, and what they are used for.
Poor (PM), intermediate (IM), extensive (EM), and ultra-rapid (UM) metaboliser.
It is used to predict therapeutic and adverse response after the administration of CYP2D6 substrates.
Do active form drugs have an immediate effect? What about prodrugs? What happens when these two kinds of drugs are metabolised by the liver? What happens when there is a polymorphism that adversely affects liver enzyme function?
Active form drugs have an immediate effect, and once metabolised by the liver, are inactivated and subsequently removed. Polymorphisms adversely affecting liver enzymes will result in impaired inactivation, and thus, impaired elimination, and accumulation will result, causing adverse effects.
Prodrugs must be metabolised to their active forms by the liver in order to have an effect. Polymorphisms adversely affecting liver enzymes will result in impaired drug conversion to the active form, and thus, lower (or no) therapeutic effect.
