Pharmacology basics Flashcards
Cover the basic terms and understandings of pharmacology
Define: a medicine
Any substance administered which may restore, correct or modify physiological function
Define: Pharmcology
The science of chemicals (food and medicine) and how they interact with the body
Define: pharmacodynamics
What the drug does to the body; the drug affect
Relationship between the concentrationn of drug at the action site and the response produced by the drug in the patient
Define: phwrmcokinetics
The way the body affects the drug over time:
Define: therapeutics
The branch of medicine concerned with the treatment of disease: translating action of drug into benefit for the patient
What are the 4 main target groups of drug action in pharmacodynamics?
- Receptors (lock and key)
- enzymes
- carrier molecules/transporters
- ion channel
Explain: receptors - lock & key (drug action)
Drug is the “key”, aiming to bind to the specific “lock”/receptor. Broken into agonist, partial agonists, or antagonists
They are protein molecules, usually found on the cell membrane, and usually respond to chemicals in the body
Explain: agonists (3 points)
Mimic the naturally occuring substrate that would usually respond to receptor site (mostly found on cell membranes)
Produces transduction mechanism on binding that causes a cascade of other effects or activating other enzymes
May also change channel shape (owning in the cell wall) to allow an influx/efflux of ions (e.g. Na, K+, Ca) which have a physiological effect
Define: partial agonists (+ example drug)
Activating receptors to produce desired response but not to a maximum level, to create a desired effect with less side effects
E.g. buprenorphine
Define: antagonists (3 points + 2 examples)
Bind and block, causing NO effect, or preventing any other drug/naturally occurring substrate to bind to receptor site.
Effect is either, - no effect or dampening down effect
Effects may be reversible or irreversible (depending on how long acting the drug is)
Salbutamol - B2 Agonist
PPI - short half life, but only OD as permanently binds to receptor site for its life
Explain: enzymes (3 points)
Proteins that speed up the chemical reaction in the body (catalysts). End in -ase
Drugs enhance or inhibit the enzymes in the physiological process within the body.
Most drugs that work on enzymes are enzyme inhibitors
Explain: enzyme inhibitors (and enzyme inducers)
Account for most drugs working on enzymes, blocking the enzyme from being metabolised.
- enzymes are proteins, and cause a substrate to be made into an “product”
- . If enzymes are prevented from being metabolised, the amount of “product” being produced is reduced, due to the substrate being reduced
Enzyme inducers do the opposite and speed up the process
Explain: HISTAMINE DIAGRAM
H2 is a histamine receptor (responsible for stomach acid production)
H2 receptor agonists have lock and key fit/receptors, reducing dyspepsia symptoms (e.g. ranitidine)
Explain: COX FLOW DIAGRAM
Cox = cyclooxygenase
NSAIDs are inhibitors - work on COX2 to reduce inflammation, pyrexia and pain, but as they are non-specific, also target COX1, giving negative effects on gastric mucus production and renal function, leading to s/e of dyspepsia, ulceration, upper GI bleed and renal failure
Explain: RENIN ANGIOTENSIN SYSTEM (RAS)
RAS important for maintaining water balance in the body and vasoconstriction, so is beneficial for control of BP.
Two enzymes involved are Renin and Angiotensin Converting Enzymes (ACE)
Angiotensin I leads to Angiotensin II production with ACE, which leads to aldosterone production, causing water and sodium retention, and causing negative feedback to reduce angiotensinogen.
ACE inhibitors - e.g. Ramipril - block after Angiotensin I, preventing ACE being produced, leading to less water and sodium retention, and so BP is lowered.
Explain: Carrier Molecules/Transporter
2 points and example
Like the “bouncers/ferry boat men”
Sit on the cell membrane and only allow passage if they have the right “properties” to be let into the cell.
Work on the action in the nerve synapse.
- drugs can affect cell transport mechanism (e.g. carrier proteins, or transporter)
e. g. Antidepressants act by preventing re-uptake of neurotransmitters
- reuptake is facilitated by reuptake transporter
Explain: Ion Channels
3 points plus drug
Drugs that affect cell transportation
Interfere with the movement of ions across cell membranes.
Ion channels are openings within the cell membrane wall, and channel blockers are the drugs mainly used here
Ion channels can also be modulators, and bind to receptors on ion channels and change the shape of them (e.g. make it wider or narrow)
CCB: (amlodipine) prevent the influx of calcium ions, which lowers BP (as calcium moves through channel following a high to low gradient, which causes contraction of vesses which would increase BO)
How do antacids work? (e.g. Aluminium chloride)
Neutralises stomach acid, does not need to go to cellular level
How do alginates work?
works like a “raft” preventing regurgitation, working in the stomach, does not need to go to cell level
How do emollients work?
Moisturise skin, don’t go to cellular level
How does general anaesthesia work?
Reduces CNS function
How do osmotic laxatives work? (e.g. lactulose, movicol)
Increase the amount of water in the large bowel
What are the two main mode of action of antimicrobials?
Bactericidal & Bacteriostatic
Explain: Bactericidal
2 points + example
Inhibits bacterial cell wall synthesis (e.g. Penecillins)
break up formation of cell wall leading to death of bacteria
