2. DEFINITIONS T1/2 & Tmax Cmax AUC 1st order kinetics
Zero order kinetics
Steady state (enteric coated, longer T1/2)
Loading doses
Therapeutic index

3. Maximum plasma concentration achieved
Amount of drugs in plasma = Bioavailability
Time to maximum peak plasma concentration
Area of plasma concentration to fall by half
Only applies to drugs with first order kinetics

4. Distribution leads to a fall in plasma concentration / achieving equilibrium within different compartments.
Vd=Q/C. When Vd is high = high affinity for lipophilic tissues seen in psychotropic drugs

5. 1-Rate of elimination independent of the amount of drug present
2-e.g fixed IV infusions, alcohol, absorption from depot
3-There is no fixed half-life
1-Applies to most drugs
2-Rate of elimination depends of the amounts of the drug present
3-Amount of the drugs eliminated in each half-life differs

6. ELIMINATION Excretion by kidneys most important
Li+: most important; What is the effect of Na+
Urinary pH: important for barbiturates
Age
Renal impairment
Also through bile or through skin

7. Steady state: after repeated dosage leading to an equilibrium between absorption and elimination
Depends on dose, time between dose and elimination half life
Achieved after 4-5 half life
Loading dosage can be given to achieve therapeutic plasma concentration
Therapeutic Index: Is the minimum plasma drug concentration causing toxic effect to that causing therapeutic effect

8. PHARMACODYNAMICS Level of actions Examples Re-uptake
Mechanism of action of drugs “The effect of the drug on the body”
Usually there is a neurotransmitter or various involved. The therapeutic effect appears to depend on the neurotransmitter that is involved (also the Side effects)
Effect can occur at various levels
Level of actions
Examples
Re-uptake
TCA, SSRI, Cocaine
Pre synaptic
Lofexidine at alpha 2
Post synaptic
D2 blockers antipsychotics
Partial agonist
Aripiprazole / Buprenorphine
antagonist
Flumazenil
Full agonist
Bzd at GABA complex
Second messenger
Lithium at inositol level