Pharmacological principles Flashcards
What is a drug
A chemical entity of known structure, other than a nutrient/dietary supplement, which causes a biological effect in a living organism
What is a medicine
A preparation of one or more drug, alongside other substances which is used therapeutically (treat, cure, prevent or diagnose disease)
How are drugs classified
- Molecular structure
- Model of action
- Therapeutic use
How are drugs named
- Chemical name
- Generic name
- Proprietary name (trade name)
What is pharmacology
The science-orientated study of drug action
What is toxicology
The study of adverse effects of chemicals on living organisms
What are the 2 main branches of pharmacology
- Pharmacodynamics (what a drug does to the body)
- Pharmacokinetics (what the body does to a drug)
What happens when the drug is administered
What is ADME
- Absorption
- Distribution
- Metabolism
- Excretion
What is the role of ADME
- Absorption + Distribution are involved in the delivery of the drug to the target site
- Metabolism + Excretion are involved in the elimination of the drug
What is absorption
Movement of drug from the site of administration to the systemic circulation (not site of action)
What must be done before a drug is administered
5 rights:
- Right patient
- Right drug
- Right dose
- Right site
- Right timing
What are the routes of drug administeration
Enteral:
- Oral
- Sublingual
- Rectal
Parenteral:
- Transdermal
- Inhalation
- Intramuscular
Describe oral drug administration
- Most common route - good for self-dosing
- Onset is rapid but drug must dissolve first
- Most drugs are absorbed by small intestine which has a large surface area and good blood supply, so large quantities can be absorbed
Why can oral drug administration be complicated
First pass effect:
- Venus drainage from most of the GI tract enters the hepatic portal vein and goes to the liver
- This means the drug is metabolised, and then excreated
Describe intravenous (IV)
- All drug reaches systemic circulation (100% bioavailable)
- Unpleasant, high risk, requires supervision
- Useful in emergency situations due to immediate onset
Define pharmacodynamics
The study of the physiological effects of drugs on the body, the mechanisms of drug action and the relationship between drug concentration and effect
How do drug targets work?
Drugs work by specifically interacting with a molecular target in order to cause/block a biological response
What are receptors
Sensing elements that coordinates the function of all different cells in the body
Give some examples of receptors
- Plasma membrane receptors
- Nuclear receptors
What is an agonist
A drug that activates receptors
What is an antagonist
A drug that blocks receptors
Whats the difference in the effects of an inhibitor, false substrate and a prodrug
Inhibitor - normal drug inhibited
False substrate - Abnormal metabolite produced
Prodrug - Active drug produced
What happens when there is an inhibitor in a transporter
The transport is blocked
What happens when there is a false substrate present
An abnormal compound is accumulated
Describe the role of blockers in the ion channels
The permeation is blocked
Describe the role of modulators in the ion channels
Increased or decreased opening probability of the channel
What is the drug dose–response curve
Shows the relationship between the level of dose and level of response
Describe how the response is a biological effect
- Quantity of proportion (freq. of seizures, mortality rate)
- Continuous measurement (blood pressure)
- Ordered descriptive category (severity of lesion)
Describe a semi-log dose-response curve
- Curve becomes sigmoidal with a linear middle portion
- Makes it easier to find the ED50 value
Describe potency
- The amount of drug necessary to produce a certain effect
- The most potent drug has the lowest ED50 value with the lowest dose
Describe efficacy
- The maximum response that a given drug will produce, irrespective of the dose (Emax)
- Greater the response, the greater the efficacy
