pharmacology summary Flashcards
(31 cards)
Affinity –
strength of association between ligand and receptor
Efficacy –
ability of an agonist to evoke a cellular response
agonist
possess affinity + efficacy
antagonist
possess only affinity not efficacy
what is pKa
pH at which 50% of drug is ionised
Henderson-Hasselbalch equation:
pH – pKa = log(A-/AH) = acid
enteral administration route
Oral, sublingual, Rectal
parenteral administration route :
IV, IVM, subcutaneous, inhalational
Vd < 10L =
vascular compartment
Vd 10-30L =
Extracellular water
Vd > 30L =
Total body water
Vd –
volume in which drug is dissolved
higher TR
safer the drug
kinetics
elimination at a constant rate
Clearance =
volume of plasma cleared of drug in unit time
when is a steady state reached
after 5 half lives
drug metabolism phase 1
RHS liver – oxidation/reduction/hydrolysis – making drug more polar
phase 2 drug metabolism
LHS liver – conjugation
Basic processes of renal excretion of drugs:
- Glomerular filtration
- Active tubular secretion: anion transporter– acidic cation transporter - basic
- Passive reabsorption across tubular epithelium
Na+flows in –
activation of Na+channels reinforcing – positive feedback
K+flows out –
activation of K+channels self-limiting – negative feedback
Sympathetic –
fight or flight [T1-L2]
Parasympathetic –
rest and digest
Neurochemical transmission steps:
- Precursor taken up
- Transmitter synthesised and stored
- Action potential depolarises
- Calcium influx through voltage-activated calcium channels
- Calcium induced release of transmitter
- Receptor activation
- Enzyme-mediated inactivation of transmitter (cholinergic) or reuptake of transmitter (adrenergic)
