General pharmacology Flashcards
Regulation allowing paramedics to hold medications
Human Medicines Regulations 2012 section 17 and 19
Law preventing carrying of medications
Medicines Act 1968
What is Patient Group Direction?
The use of medicine for a group with the same pathology relying on adequate knowledge
Pharmacokinetics
What the body does to drugs
Pharmacodynamics
What the drugs do to the body
What determines the activity of a drug
Number of receptors bound to drug
Concentration of drug at tisues
Pharmaodynamics
Dose, elimination and route of administration
Therapeutic index calculation
Toxic dose/ therapeutic dose
Lower value means more dangerous
Response on x axis
Plasma concentration on y axis
Emax
Dose for max response
ED50
Therapeutic dose for 50% of sample
LD50
Dose that is lethal to 50% of sample
4 ways the body reacts to drugs
Absorption
Distribution
Metabolisis
Elimination
Organs involved in clearing drugs from the body
Liver through cytochrome oxidase 450 which breaks down into excretable molecles which may or may not be active
Kidneys which filters into urine
Drug halflife (t1/2)
Time taken for plasma concentration to half
First pass metabolism
Drugs go straight to liver via hepatic portal vein to be metabolised
What determines drug absorption
Is it water or fat soluble
How polarised
Can it cross blood brain barrier
Size and surface area of particles
If drug needs to metabolise
Blood flow to site and contact time at site
What determines drug distribution
Is it water or fat soluble
how acidic/ alkaline
Can it cross blood brain barrier
Route of administration
Agonist
Drug binds and creates reaction
Antagonist
Drug binds blocking receptor
Competitive
Binds reversibly and competes with other molecules to bind to site
Non competitive
Binds permanently amking the receptor inactive
Inverse agonist
Binds and produces opposite reaction
Allosteric site
Site seperate to main that may active/inactive enzyme or increase/reduce reaction
Affinity
How easily molecule bonds and how strong bond is
Efficacy
How effectively molecule activates receptor
Potency
Strength of a reaction at a certain dosage
Specificity
How effective a drug is at only producing desired therapeutic effect
How does GPCR reaction work
Drug binds to receptor site which induces confirmational change. This then releases alpha sub unit which can either affect an enzyme which continues on as messenger cascade or may bind to a channel to allow the passage of a molecule that otherwise would not be able to pass the membrane in the same way.
Examples of GPCR
Adrenaline binds at beta 2 receptors which increases messenger cAMP causes bronchodilation and relaxation of smooth muscle
Actions of adrenoreceptors
Alpha 1 - Vasoconstriction (increases BP).
Beta 1 - Increases heart rate and force of contraction. Reduces refractory time of heart
Beta 2 - Bronchodilation, skeletal muscle tremor. Increases blood sugar
Other receptor type
Nuclear receptor site used by steroids as these can pass through cell membrane
