Define “Pharmacokinetics”
How the drug is altered as it travels through the body
Define “Pharmacodynamics”
Mechanism of Action
Name the 2 Types of Pharmacologic Action
- Drugs which change the environment of body cells
2. Drugs which bind to receptors on cell membranes and alter cellular physiology
What can Influence Drug Responses?
- Age
- Gender
- Weight
List the 4 processes in Pharmacokinetics
- Absorption
- Distribution
- Metabolism
- Excretion
What factors influence absorption of medication?
- Lipid Solubility
- Surface Area
- Blood Flow at Administration Sites
- Age
- Organ Health
How does the “Absorption” process work?
- Medication passes from source of administration into the blood stream
- Involves active and passive transport
How does the “Distribution” process work?
- Depends on blood flow and ability to cross cell membrane
- Organs w/ large blood supply receive the medication quickly (heart, liver, kidney)
- Skin, fat, muscle receive medication slow
How does the “Metabolism” process work?
- A.k.a. biotransformation
- The ability to change the drug from its dosage form into a water soluble form, which is then excreted
- Most drugs are metabolised in the liver
How does the “Excretion” process work?
- The elimination of drugs from the body
- Most drugs are excreted by the kidneys
Define “Half-Life”
The amount of time it takes for half of that drug to be eliminated by the body
What is an Additive Interaction?
2 drugs working together simultaneously
What is an Antagonistic Interaction?
Less than the desired effect of one or both of the drugs
What is a Synergistic Interaction?
Total effect greater than if they were given alone
What is an Incompatibility Interaction?
Often causes drugs to precipitate out of solution or it may cause a visible change in colour
Define “Receptor”
Receives chemical information from other molecules
Define “Natural Agonist”
Substances within the body that produce responses when they bind to and “switch on” a receptor (the master key)
Define “Agonist”
Mimic natural agonists, binding to receptors to create the same effect - greater physiological response
Define “Antagonist”
Binds to receptor and blocks agonist’s access to receptor
List the Drug Families
- -ocaine = local anaesthetic
- -cillin = penicillin
- -olol = beta blockers
- Ceph- = cephalosporins
- -statin = HMG-CoA inhibitors
- -pril = ACE inhibitors
- -azepam = benzodiazepines
