Basic pharmacology Flashcards
What is pharmacology?
The science of drugs or the science that deals with the effects of drugs on living systems
What is medical pharmacology often defined as?
The science of substances used to prevent, diagnose and treat disease
What is a drug?
A drug is any substance or product that is used or intended to be used to modify or explore physiological systems or pathological states for the benefit of the recipient
What are the two main divisions of pharmacology?
Pharmacokinetics
Pharmacodynamics
What is pharmacodynamics?
The study of the mechanism of action of a drug, its pharmacological actions and its adverse effects (what a drug does to the body)
It also studies the dose/response relationship
What are the 4 parts of pharmacokinetics?
Absorption
Distribution
Metabolism
Elimination/excretion
What are the 2 main parts of pharmacodynamics?
Efficacy
Toxicity
What can the main types of drug action be broadly classified as?
Stimulation
Depression
Irritation
Replacement
Cytotoxic action
What is pharmacokinetics?
The movement and alteration of a drug within the body, “what the body does to the drug”
What is drug absorption?
The movement of a drug from site of administration into systematic circulation
What factors affect drug absorption?
Physical state
Particle size
Disintegration
Lipid/water solubility
Drug pH
Chemical nature
Concentration
Route of administration
Area of absorption surface
Vascularity
Presence of other substances (food, drugs etc.)
Gastrointestinal and other diseases
Are liquid or solid forms of drugs absorbed faster?
Liquid
Are lipid or water soluble drugs absorbed greater?
Lipid soluble
What pH drugs are better absorbed?
Weak acids and weak bases are better absorbed that strong acids and strong bases
Where are acidic drugs absorbed from?
The stomach
Where are basic (alkaline) drugs better absorbed?
The intestine
When are salt forms of drugs better absorbed than organic compounds?
When administered orally
What is bioavailability?
The rate and extent of absorption of a drug from a dosage form as determined by its concentration-time curve in the blood i.e. the fraction of a drug that reaches systemic circulation from a given dose
What route of drug administration gives 100% bioavailability?
Intravenous
Why does the oral route give lower bioavailability?
The drug may be incompletely absorbed
First pass effect
What is drug distribution?
The reversible transfer of drugs between body fluid departments (the extracellular fluid and tissues)
What happens after drug absorption?
It enters the systemic circulation and is distributed in body fluids
What immediately follows intravenous drug administration?
Distribution, as there is no initial absorption
What does drug distribution from the plasma to the extracellular fluid depend on?
Cardiac output
Binding of drugs to plasma proteins
Binding of drugs to tissue proteins
Lipophilicty