Introduction to clinical pharmacology

    INTRODUCTION TO CLINICAL PHARMACOLOGY 

INTRODUCTION :

·       Pharmacology is the study of the biological effect of chemicals. In clinical practice health care provider focus on how chemical act on living organism. Nurse deal with pharmacy therapeutics or clinical pharmacology involving drugs used to treat, prevent or diagnose disease.

·       Pharmacology is a study of effective and safe use of drugs in the diagnoses prevention and treatment of disease.

Chemical medicine (2500 BC is probably the oldest. Sumerian tablet (2100 BC ) describe ointment and medicines containing asafetida sodium chloride and potassium nitrate. Ebers papyrus (1550BC) contains prescription of castor oil and opium.

 

In modern time Hippocrates (370-460 BC) who is called father of medicine.  He postulated the modern concepts of disease and separated it from ghosts.

 

Aristotle (322-384 BC) separated superstition from fact.

 

Galen (131-201 AD) encouraged the idea of polypharmacy.

 

Paracelsus (1493-1541 AD) encouraged the idea of polypharmacy.

 

Paracelsus (1493-1541 AD) started using Marcu rial’s   in the treatment of syphilis.

 

·       Drug : A drug is defined as any substance which is used to cure diagnose or prevent a disease.

·       Main divisions of pharmacology :  The subject matter of pharmacology includes the following main divisions.

 

1.      Materia medica: Which deals with source, description and preparation drugs.it is an old branch of pharmacology.

2.      Pharmacodynamics: Which deals with biochemical and physiological effects of drugs and also their mechanism of action. (what the drug does to the body).

3.      Pharmacokinetics: which deals with the absorption, distribution, metabolism and excretion of drugs. (what the body does to the drug).

4.      Therapeutics: which is concerned with the use of a drug for curing diseases and relieving their symptoms.

5.      Clinical pharmacology: Which is the scientific study of drugs in man. The efficacy and safety of a drug is studied in patient’s and healthy volunteers.

6.      Chemotherapy: which deals with the effect of drugs on micro-organism and parasites which occur in a living organism.it also includes the treatment of cancer.

7.      Toxicology :which deals with poisonous effects of drugs, detection of poisoning and its treatment.

 

Drug standards: The government of most of the countries have established legal standards for all important drugs. These standards are published in pharmacopeia which is an official code containing a list of established drugs along with their standard. The following are some well-known   pharmacopoeias:

1.      The Indian pharmacopoeia (I.P).

2.      The British pharmacopoeia (B.P).

3.      The United States pharmacopoeia (U.S.P).

 

  Sources of Drags:

  1.Plants : Till the beginning of this century leaves, barks or roots were used to treat diseases Quinine, morphine, ephedrine and digoxin are still in use chemical purification of these products yielded active ingredients like alkaloids (morphine atropine, emetine and quinine), glycosides (digitalis), fixed oils (castor and peanut oil) and volatile oils (asafetida, ginger eucalyptus).

2.Mineral oil : liquid paraffin is used as purgative.

3. Heavy metal and Minerals : Mercury was used in syphilis and as an antiseptic.

   Magnesium trisilicate is used as an antacid in peptic ulcer. Radio-active minerals (133I,32P) are used for diagnosis and treatment of cancer.

4.Animal products : Following substance are derived from animals and used in human.

Insulin : In diabetes mellitus, thyroid extract for myxedema, liver extract for pernicious anemia, gonadotrophins in hormonal disturbances, antitoxic sera and antivenom  for toxins and snake bites.

5.Synthetic : Majority of the drugs these days are synthetic.

Advantage :

(a)   These are available in pure form and therefore quality is better controlled.

(b)   Easy to manufacture in bulk

(c)    Are cheaper.

(d)   Drugs can be chemically modified so as to possess more effective and more specific actions

Examples of synthetic drugs-aspirin, glucocorticoids, calcium channel blockers, sulfonamides.

6. Microorganism : Certain important drugs have been obtained from bacteria and fungi (penicillin and bacitracin ). Lately insulin is also being development from bioengineered micro-organisms.

Concept of pharmacology :

A drug or medication is any substance that modifies body functions when taken into the body the study that deals with chemicals that affect the body’s functioning is called pharmacology. A pharmacist is a person licensed to prepare and disperse drugs. The physician is legally responsible for prescribing medication. The physicians and nurse practitioner conveys the medication plan to others by an order called a prescription. After the pharmacist prepares the medication nurse administer the medication to the patient. This chain provides a check and balance system for medication administration.

Drug nomenclature

Drugs have several name. the chemical name is precise description of the drug’s chemical composition; it identifies the drug’s atomic and molecular structure. This name is significance to pharmacist. The generic name is the name assigned by the manufacturer that first develops the drug. The official name  is the name by which the official name is the name by which the drug is identified in the official publication. The trade name also referred to as the brand name or property name, is selected by drug company that sells the drug and is copyrighted.

Nurse should familiar with drugs generic and trade name.