Purpose
of medication
Medication
is a substance administered for the diagnosis, cure, treatment, or relief of a symptom
or for prevention of disease.
Words
like medication and drug are generally used interchangeably.
Crude
drugs, such as opium. Castor oil, and vinegar, were used in ancient times.
The
written direction for the preparation and administration of a drug is called a prescription.
Purpose:
·
For treating diseases
·
For cure and treatment
·
Relief of symptoms
·
To promote health : drugs arc given to the
individual to increase the resistance eg. Vitamins
·
To prevent diseases e.g. Vaccines and
antitoxins
·
To diagnose diseases e.g. Barium used in X
ray studies
·
To alleviate diseases: certain drugs are
given for the palliative effect or for the temporary relief of symptoms but
does not remove the cause or cure the disease e.g. Analgesics
·
For cure and treatment:
▪
By restoring normal functions e.g. Digoxin
▪
By supplying a substance that is deficient
in the body e.g.lnsulin
▪
By destroying the causative organisms e.g.
Quinine in malaria
▪
By counteracting with the toxic substances
circulating in the body e.g.. Antidotes
▪
By stimulating lhc functions of an organ
or a system e.g. Stimulants
▪
By depressing thc functions of an organ or
a system e.g. Sedatives
Medication
Four
kinds of names: its generic name,
official name, chemical name, and trademark or
brand name.
Generic name
is given before a drug becomes officially an approved medication.
The chemical name
is the name by which a chemist knows it; this name describes the constituents
of the drug.
Trade name
is the name given by the drug manufacturer. The name is usually selected to be
short and easy to remember. Sometimes called the brand name. For Example, the
drug hydrochlorothiazide (official name) is known by the trade names
Esidrix and hydrodiuril.
Principles of drug action:
Pharmacokinetics
is the process by which a drug moves through the body and is eventually
eliminated.
Pharmacodynamics
refers to the physiologic and biochemical effects of a drug on the body.
Understanding these processes helps in evaluating therapeutic and adverse
effects of medications.
Pharmacokinetics
Pharmacokinetics
involves the absorption, distribution. Metabolism and excretion of a
medication. Each medication has its own characteristic rate and manner by which
it is absorbed by body tissues, delivered to reactive cells, transformed to
harmless substances, and removed from the body.
Absorption is the process by
which a medication enters the blood stream. The route of administration affects
how quickly and completely a medication is absorbed. IV (Intravenous)
administration offers the quickest rate of absorption followed in descending order by IM (intramuscular), Subcutaneous
and PO (per oral) routes.
Distribution
is -the process by which the medication is delivered to the target cells and
tissues. The effectiveness of the circulatory systeme, the amount of medication
bound to protein, and the tissue specificity of the drug affects distribution.
Metabolism-
Is the process of chemically changing the drug in the body. Metabolism takes
place mainly in the liver. Alterations in. Liver function, including decreased
function that occurs with aging or disease affects the rate at which drugs are,
metabolized.
Excretion
is the process of removing the drugs or its metabolites from the body. The
kidneys excrete most drug metabolites. Some excretion also occurs in the lungs
and the intestines. Decreased kidney function adversely affects drug excretion.
Pharmacodynamics
Drug
activity is the result of chemical interactions between a medication and the
body's cells to produce a biological response. Most drugs interact with a
cellular component to initiate a series of biochemical and physical changes,
resulting in the drug's effects. These biological and physical effects can be
local or systemic. For example, local effects are seen When moisturizing lotion
is applied to chapped skin.
Systemic
effects can affect one or more body systems. For e.g. When analgesics (pain
medications) are administered, effects on sedation (nervous system,)
respiratory rate and depth (lungs) and constipation (gastrointestinal tract)
are seen.
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