What are drugs
Chem sub interacts with a bio system to produce physiologic effect on cells
Natural or synthetic
What is pharmacology
Action of natural chemicals in thebody
• Origins and sources ofdrugs
• Chemical structureand physical characteristics of drugs
• Mechanism ofdrugaction
• Metabolism and excretion of drugs
• Study of drug actions in humans and their therapeutic uses
• Study of drug actions on organs,tissues,cells,enzymes,DNA, animals
Pharmacokinetics vs pharmacodynamics
pharmacokinetics - what happens to drug after administration: mvt into, thru and out of body.
4 processes ADME
Absorption
Distribution
Metabolism
Elimination
pharmacodynamics- the effect the drug has on the body
Routes of drug administration
Oral - tablet/capsule/liquid.
Topical- cream,ointment,drops, spray, gel
Intravenous
Intramuscular/ subcutaneous(under the skin)
Buccal( mouth, no swallow)
Rectal
Vaginally
Transdermal
Inhalation
Ads and disad of oral administration
Absorbed via GI tract
enters bld stream
AD- easy
DISAD- unpleasant taste, upset stomach, stomach acid reduce effectivity
which method of drug admin that optoms use
topical
X enter bld stream
small amt of systemic absorption via tear drainage
what are the 3 types of routes that drugs can be absorbed? Describe the absorption from GI tract.
Drugs damaged by enzymes and stomach acid
molecule thru hepatic portal then bld stream
IV drugs not absorbed. Enter bld stream directly
What is bioavailibility?
the fraction of a drug dose that reaches bld sream in active form
IV = 100% bioavailibility
affected by first pass metabolism
What are the 2 main processes that drugs use to enter cells
Diffusion- passive
simple- semi perm mem
facilitated- mem protiens
Active Trans- active
What is drug distribution andwhat factors affect it?
transport of drug from bld to site of action
affected by:
Aqueous solubility- H2O X well distributed
Lipid solubility- better distribution
Molecular size- smaller = better
Bld barriers & blood flow perfusion
Plasa protien binding- if pro bind to drug, not distributed
Tissue sequestration- drug stored in tissues
What is drug metabolism and what factors affect it?
enzymatic conversion of a chem cpd to its metabolite.
drugs metabolised in the liver- phase 1 and 2
factors:
diease state, age, drugs, genetics, enviro,nutrition
What is the half life of a drug
time for drug concentration to drop from max to half
short half life=more frequent drug administration
high conc in plasma = absorption/ low conc = met and excretion
what is drug excretion? factors affecting it and routes
clearance of drugs from the body
factors: route of excretion/drug solubility/half life/degree of ionisation/renal and hep bld flow
Routes:sweat, tears, skin, urne, feaces, lungs, saliva, kidneys
What are the principal of drug actions (pharmacodynamics)
SCRD
Stimulation- selective enhancment of activity of specialised cells eg adrenaline to stim heart rate
Cytotoxic action - cause to die without affecting host cell eg penicillin
Replacement- use of natural metabolites where deficiency eg Fe for anemia
Depression- selectively inhibits cells
What are the anti infectives drugs
Antibiotics- either bactericidal or bacteriostatic/ gram +ve or -ve based on how they stain. If both= broad spectrum
Antibacterials
Antifungal
Antivirals- block replication of viral DNA. end in “…clovir”
Antiprotozoals
what are the 4 drug targets? describe them
Receptor: stimulus>neurotrans>cleft>binds.
Agonist - produce response
Antagonist- blocks receptor so X response
Enzymes: bio catalyst>substate>product
Ion Channel: selective.
Channel blockers- drug blocks channel eg anaesthetics
Channel modulators- drug alters permeation
Carrier pro- ions>ATP eg antidepressants preent reuptake of neuro in syanptic cleft
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