Methods of Administration, Bioavailability, Agonists/Antagonists Flashcards
What is a drug/medicine?
Any chemical (natural/man-made) which alters:
- incoming sensory sensation
- the psychological state (mood/emotion)
- the physiological state
What are the 5 methods of administering drugs?
dermally (limit effect to the site of disorder)
oral (mouth)
inhalation
rectal (through anus)
parenteral (injection)
- intramuscular (arm, leg, buttock)
- intravenous (into blood vessel (most rapid)
- subcutaneous (fatty tissue under the skin)
What is bioavailability?
What factors affect bioavailability?
The fraction of the administered dosage that reaches the bloodstream, important when calculating how much of a dose to administer
Water solubility: important for circulation in the aqueous solution in the blood
Lipid solubility: helps in the passage of the drug through membranes during absorption
The presence of polar groups (dissolve in water)
The presence of functional groups that can undergo ionization (COOH, NH2) (dissolve in water)
What is drug action?
What is drug effect?
What is side effect?
the interaction between the drug molecule and the biological tissue
the desired physiological effect
undesired physiological effect (can be positive or negative)
ex) aspirin for pain relief and anti-inflammation also things the blood and can prevent strokes (arterial blockage)
What is the structure-activity relationship?
The relationship between drug molecules and receptor sites
Drugs can mimic neurotransmitters and bind to the receptor sites in the CNS; may activate or inhibit the neuron
Receptor sites (protein molecules) will change their quaternary structure depending on the interaction with different molecules
What is an agonist?
What is an antagonist?
What is competitive vs non-competitive antagonism?
Agonist: drugs that mimic neurotransmitters and stimulate receptors ex) heroin (agonist) binds to opiate receptors (responsible for analgesic and euphoric sensations); blocks release of endorphins (which block pain, provide euphoria)
Antagonists: drugs that interfere with neurotransmitters (stopping their production, or competing for receptor sites)
Competitive antagonists mimic the neurotransmitter and have a greater affinity for the receptor (ex. Curare a comp. antagonist for acetylcholine, Curare binds to receptors and prevents acetylcholine from sending messages, causing paralysis)
Non-competitive antagonism: stops the transmission of neurotransmitters (ex. Gallamine stops the effects of acetylcholine but binding to a different receptor further along the transmission process, and stopping the transmission of acetylcholine’s message)
