Basis of Drug Effects
A drug is given to
Prevent, Diagnose or
Treat a disease or
condition

The effect that a drug
exerts is directed
toward one of those
three goals.



Think of a receptor as
a lockAnd the drug as a key
Receptors are special
protein molecules
located on the cell
membranes of every
cell.
ANGONIST
 An AGONIST Drug
(KEY) unlocks and
activates a receptor
(lock)
ANTAGONIST

An ANTAGONIST
drug (KEY) occupies
and BLOCKS a Receptor
(lock)

Receptors
There are many different
types of receptors, including
those that respond to
histamine, which are known
as
H1 and H2 receptors.
SYSTEMIC
A Systemic
Effect is felt
throughout the
body.
Drugs taken
orally usually
exert a
systemic effect
Therapeutic
Effect
The
Therapeutic
Effect is the
drug’s main
action for
which it was
prescribed

The therapeutic Effect
of a drug can be
directed toward the
specific area of the
body that has the
disease-toward a
target organ

Severe side effects are
often referred to as
Adverse Effects,
though Adverse
Effects are not
commonly observed
as side effects


The FDA can remove
a drug from the
market if reports of
Adverse Affects on
patients are severe.
drug
patient
ZELNORM



-Approved by the FDA
in 2002 for the treatment
of irritable bowel
syndrome
-Approved a second
time for the use of
chronic constipation
-the drug was heavily
advertised on television

Zelnorm was removed
from the market in 2007
because of a significant
increase of heart attack
and stroke in patients
using this drug.

Toxic effects result
when the serum level
of a drug rises above
the therapeutic level
to a higher level that
is TOXIC.

When a drug has a
low Therapeutic Index
it has a narrow
margin of safety
between what is
considered a safe dose
(therapeutic) and toxic
dose

An allergic reaction is
a type of side effect
that differs from other
side effects because of
its specific underlying
cause: the release of
histamine.
HISTAMINE

The word allergy was
introduced in the early
1900’s. An allergy is a
reaction that occurs
when the body’s
immune system
identifies a foreign
substance –known as an
Antigen and initiates an
antibody response
against it.
ANTIGEN-ANTIBODY


An Antigen (pollen,
dust, weeds, or a
drug)does not provoke
an allergic reaction in
everyone.
The presence of the
antigen combined with
an antibody stimulates
the release of histamine.
PHARMACOGENETICS

Is the study of how the
genetic make-up of
different people affects
their response to certain
drugs
POLYPHARMACY


Many patients take
more than one drug,
some take several
different medications at
once on a daily basis.
Polypharmacy increses
the likelihood of drugdrug interaction.

The way to
MAXIMIZE a drug’s
therapeutic effect is to
minimize the occurrence
of adverse or toxic
effects, by taking the
drug EXACTLY as
prescribed.

Although Elvis
Presley officially died
of a heart attack in
1977, medical
examiners discovered
that he had been
prescribed over 12,000
pills, tranquilizers,
sedatives, painkillers,
stimulants…in the 18
months prior to his
death.

The pharmacist
applies warning labels
to the prescription
bottle to warn the
patient of a possible
drug-drug interaction
food or alcohol
interaction or other
side effect.


Drug-Food InteractionsWhen some drugs
interact with certain
foods, they may cause
the drug effect to be
lessened or counter
therapeutic.

Example: Grapefruit
juice, although delicious
and nutritious, can
cause serious side
effects when mixed
with some drugs,
because it blocks
enzymes in the
intestines which can
break down the drug
before it can even enter
the bloodstream.



In the 1700’s the
Apothecary system
was brought over
from England.
The word Apothecary
means a person who
combined and
dispensed drugs.
Some apothecary
measurements are
still used today

Apothecary system of
measurements
include: the minum,
grain, scruple and
dram.


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There Are Five Rights
of Drug
Administration:
The Right patient
The Right drug
The Right dose
The Right route
The Right time

Do it RIGHT the first
time!