introduction to clinical pharmacology

GENERAL DEFINITIONS
Pharmacology: is the branch of
medicine that study the interactions
occurs between a living organism and
drug.
? Pharmacokinetics refers to what
the body does to a drug.
? Including
? absorption,
? distribution,
? metabolism,
? excretion.
? DRUG:
? any substance that exerts effect on
the cell, tissue, organ within the body.
? used for :
? diagnosis,
? prevention,
? treatment of disease
? Dose:
? amount of drug necessary to elicit the
desired therapeutic response
? Drug abuse:
Excessive non-medical or social drug use.
? Addiction (Physical Dependence)
This generally occurs with alcohol, and
tobacco.
? TOLERANCE
the response to the dose of the drug
decreases with repeated use, so person
need for higher dose to reach same
response.
? Withdrawal Symptoms
When one has become physically
dependent on a drug and suddenly
stop taken it, a psychological and/or
physiological reaction occurs which is
the opposite of the effect of the drug.
? Placebo: a treatment with a certain drug
that is supposed to have a certain effect,
but it has no specific biological activity.
Placebo used for two purpose:
? As control in scientific evaluation of drugs.
? To treat patient by psychological way.
? Agonist: substances that bind with receptor and
produce maximum response that mimic the
response of endogenous ligand.
? have affinity and efficacy
? Partial Agonist: Substance that bind with
receptor but not give maximum effect as full agonist
even all receptor are occupied (there is no Emax)
? Antagonist:
a drug that does not provoke a biological response
itself but blocks agonist-mediated responses.
? have affinity but no efficacy.
? Efficacy: (Emax)
Is ability of drug to produce maximum effect or
response.
Depend on number of drug-receptor complex.
Potency:
is the minimum concentration that produce fifty
percent of response (EC50).
Depend on Affinity of drug for receptor? Therapeutic index:
? measure drug safety.
? Is ratio of dose that produce toxicity to the
dose that produce a clinically beneficial effect in
population
?
TI=TD50/ED50
?
Large value mean wide range between effective
and toxic dose.
? Half life ( t1/2):
? the time taken for the plasma
concentration to fall by half,
? is a constant.
? Side Effects: is an effect of the drug other
than the one for which it was administered.
? Some side effects can cause serious
problems ,stomach bleeding from aspirin.
? Iatrogenic diseases:
? diseases results from treatment of other
disease.
? Like Cushing syndrome results from
systemic steroid therapy.