Pharmacology Flashcards
tablets
drug + substance to bind drug + filler (bulk) + disintegrator (dissolves in body)
Enteric-coated
unaffected by acid in stomach → disintegration takes place in SI
- useful for drugs which irritate the stomach
capsules
enclosed in gelatine shell → disintegration takes place in stomach
sustained-released preparation
released slowly into GIT over extended period
- prepared in layers
oral liquid
mixtures/suspension
drops
ear = oily nose = water eye = water/oily based
cream and ointment
creams = aq ointments = lipid based
sublingual/buccal
susceptible to breakdown by liver enz/gastric juices
suppository
solid→liquifies at body temp → abs through rectal mucosa & BV
enemas
liquid preparations for rectal admin
pharmocokinetics
ADME
absorption
movement across membrane
distribution
vd, bioavailability (how much drug available for use after abs)
(iv gives 100% bioava)
metabolism
phase 1 - make drugs bioavailable
phase 2 - active drugs become inactive and excreted
- lipophilic → converts to hydrophilic compound
- BUT could also be used to activate drugs
elimination
excretion (urine/faeces)
pharmacodynamics
actions of drug
- affinity and efficacy
- increase dose and increase AE
drug abs - oral
movement from mouth to blood
- abs in SI → simple lipid diffusion
factors affecting drug abs
content GIT
chem property of drug
SA of gut and GIT
molecular size and weight
bioavailability
amount of active drug enters plasma
steps of drug distribution
- driven by blood circulation
- dilution in blood → move to ECF → uptake into cell
factors affecting drug distribution
ability to cross endothelium
protein binding
factors affecting drug metabolism
genetics, age, disease, smoking, interactions
drug interactions outside body
GTN oxidises in air
Asprin hydrolyses to acetic acid + salicylic acid from moisture
drug interactions inside body
grapefruit juice interacts with drugs
