Pharmacology Flashcards
What is meant by an idiosyncratic side effect?
A side effect that only happens to you i.e. uncommon
What is a drug?
An external substance that acts on living tissue to produce a measurable change in the function of that tissue.
Generally act to stimulate or interrupt normal body communications.
They also act on non-host organisms to aid body defences.
What drug types are commonly used in dentistry?
Local anaesthetics - prevent pain
Antimicrobials - treat and prevent infection
Anxiolytics - reduce anxiety
Analgesics - reduce post op pain
Compare hormone and neural messages.
Hormone - slow, general info to all tissues
Neural - fast, target info for specific tissues
What nervous system involves adrenaline release?
Autonomic nervous system
- Sympathetic
What are the different branches of the body’s nervous system?
Central Nervous System/CNS
Peripheral Nervous System/PNS
- Autonomic (involuntary)
- > Sympathetic
- > Parasympathetic
- Somatic (voluntary)
What is the effect of the sympathetic NS on heart rate?
Adrenergic stimulation (adrenaline) Speeds up heart rate via Beta-receptors
What is the effect of the parasympathetic NS on heart rate?
Cholinergic stimulation (acetyl choline) Slows the heart via cholinergic receptors
What are the effects of adrenaline?
Beta agonist Increases h.r. Increases b.p. Increases force of contraction Bronchodilation Enlarges pupils *Part of the body's fight or flight response, released in response to stress
Where is adrenaline produced?
Medulla of the adrenal glands
What is atenolol?
Beta blocker - slows heart rate
Used to treat angina, hypertension and in preventing heart attacks.
What is pilocarpin and what are its actions?
Cholinergic agonist
Mimics the actions of acetyl choline
Vasodilation, decreased heart rate, bronchiole constriction
What is atropine and what is it used for?
Cholinergic blocker - blocks ACh receptors
Used for asthma, diarrhoea and nausea
How do drugs interact with tissues?
Receptors Enzymes Ion channels G-proteins Gene transcription
What is an agonist?
A drug which stimulates a receptor in turn producing the full response of that receptor
What is an antagonist?
A drug which binds to a receptor but has no effect i.e. blocks the action of that receptor
What factors affect drug-receptor interaction?
Affinity - the attraction of the drug to receptor affects the likeliness to bind
Occupancy - response of body is directly proportional to the amount of drug bound (occupied receptors)
What factor affects the drug induced response?
Efficacy - how much effect a specific drug has on the body system
*the more drugs/receptors, the more chance of the drug being effective
What is a partial agonist?
Compounds that can activate receptors but are unable to elicit the maximal response of the receptor system.
What is a competitive antagonist?
Binds to receptors in a reversible way without activating the effector system for that receptor. It’s effect can be overcome by increasing the conc of the agonist.
e.g. atenolol
What is a non-competitive antagonist?
Binds to receptors and reduces the available receptors for the agonist - irreversible. It’s effects cannot be overcome.
e.g. phenoxybenzamine
What is the path of drugs?
Gut - oral (via HPV) Liver Vein - intravenous (via IVC) Heart (via PA) Lungs - inhalation (via PV) Heart (via aorta) Arteries Sytemic circulation - subcutaneous
What are the different routes of drug administration?
Enteral - oral Parenteral - intravenous - intramuscular - subcutaneous - inhalation
What are the phases of drugs in the body?
- Absorption
- Distribution
- Metabolism
- Excretion
ADME
What are the pros and cons of enteral drug administration?
Socially acceptable, easier for patients
Slow onset, variable absorption (unpredictable), gastric acid of stomach may destroy drug, first pass metabolism
What is first pass metabolism?
Drugs in the gut will pass to the liver via the hepatic portal vein. It is metabolised in the liver before it reaches the systemic circulation where it can have an effect. This means only a portion of the drug consumed becomes active in the bloodstream. First pass metabolism can either activate or deactivate the drug.
*Consider patients liver function when creating doses (age, liver failure etc)