INTRODUCTION TO PHARMACOLOGY by Dr Bilal Aslam.pptx

Introduction to Pharmacology by Dr. Bilal Aslam

1. INTRODUCTION TO PHARMACOLOGY Dr. Bilal Aslam Associate professor Institute of Physiology and Pharmacology

2. Terminologies Pharmacology: This term originated from Greek words; pharmakon , which means “a drug” and logos , which means “a rational discussion or study”. Generally, it is defined as the science of drugs. Drug A drug may be defined as: A chemical, physical or biological agent used for the treatment, prevention and diagnosis of animal diseases. Contraceptive Drugs: Agents which are used for the prevention of pregnancy (which is normal physiological process) Any substance other than food items which is used for safeguarding the health of the human being and animals. Anything enlisted in pharmacopeia.

3. Terminologies Pharmacopeia It is an official publication which contains all the necessary information about the drugs. For example; B.P = British pharmacopeia U.S.P = United States pharmacopeia E.P= European Pharmacopeia

4. SOURCES OF DRUGS The drugs of therapeutic values are obtained from plant, animal and mineral sources. However, during the last few decades, an increasing number of organic drugs have been obtained by the synthetic source in the chemical laboratories. Different common sources are enlisted below: 1. Plant Source: Previously the roots, leaves and barks of plants were the main source of drugs. Various classes are of current interest includes;

5. SOURCES OF DRUGS 1) Alkaloids : Define; The alkaloids are basic nitrogenous substances which are widely distributed in many plants. For example: Strychnine – the alkaloid of the plant, nux vomica . Atropine – from atropa belladonna. Morphine, codeine and pathidine – obtained from opium. Opium contains more than 30 alkaloids. 2) Glycosides : The glycosides are those compounds which contain a sugar moiety, on hydrolysis give glucose and other substances (i.e. aldehyde , alcohol) For example: Digoxin – obtained from plant, digitalis purpurea , called fox gloves.

6. SOURCES OF DRUGS 3) Gums: They are viscid bodies obtained by collecting the exudates from the incised leaves and branches of certain plants. For example; Gum acacia – obtained from acacia Arabica. Gum tragacanth . 4) Oils There are usually two types of oils on the basis of their physical nature; i ) Fixed oils: like cotton seed oil, olive oil ii) Volatile oils: also known as aromatic oils or flavoring oils – like clove oil, oil of peppermint and oil of spearmint. 5) Resins: Resins are solid plant substances that are also found as liquid exudates of certain plants / trees. 6) Tannins : These are non-nitrogenous substances having an irritating or astringent action on mucous membrane. For example: Catechu tannin – obtained from catechu.

7. SOURCES OF DRUGS 2. Synthetic Source It is the biggest source of drugs now a day. In 1908, first time a textile dye Prontosil was tried in vitro , on a culture medium of some microorganisms. Then it gives no reaction against organism. After that, when it was tried in vivo, it proved lethal for bacteria. Inside the body (in vivo), Prontosil converted into sulfanilamide, which has great action against bacteria. Thousands of compounds (called analogs) are derived from this parent compound substance, sulfanilamide. Sulfonamides: These are derivatives of sulfanilamide.

8. SOURCES OF DRUGS 3. Animal Source - Desiccated thyroid: is used still in the treatment of hypothyroidism. - Insulin: is extracted from the pancreas of ox. - Pituitary extract: has been used to stimulated uterine contractions. 4. Biotechnology: It is an important source of drugs now-a-days. oxytocin is now prepared though genetic engineering. Through genetic engineering, insulin is now produced by E.coli bacteria. This insulin is 100% pure and similar to that of human beings in all aspects. 5. Mineral Source: Today, iron’s purified form is used for treating certain type of anemia. Many other minerals are employed in the treatment of diseases. For example; Iodine – in goiter, Magnesium sulphate – as purgative and potassium nitrate – as diuretic.  

9. NOMENCLATURE OF DRUGS In order to name the drugs, there are two systems; i ) Generic Name : ( Syn : official name, approved name, non-proprietary name) “The name which is assign by the drug nomenclature commissioner of World Health Organization (WHO). ii) Brand Name : ( Syn : trade name, non-official name, proprietary name and business name). “The name which is assigned by the drug manufacturer. Brand name of drug is quite irrelevant to any aspect of the drug, i.e. chemistry. For Example ; 1) Paracetamol - a generic name ---- Panadol , Calcol , Disprol – are brand names of this drug 2) Novidate – a brand name of an antibiotic with the generic name – Ciprofloxacin.

10. BRANCHES OF PHARMACOLOGY As pharmacology is the science of drugs, it includes various pharmacological disciplines as follows; 1. Pharmacy: The branch of pharmacology that deals with the preparations, compounding, dispensing and labeling of the drugs. 2. Pharmacodynamics : It is the branch of pharmacology that deals with the biochemical and physiological actions of the drugs and mechanism of action of drugs on body. 3. Pharmacokinetics: It is the branch of pharmacology that deals with the absorption of drugs, distribution of drugs, metabolism and excretion of drugs. OR It is mathematical discipline which deals with the study of changes in drug contractions as a function of time. Important Note: What the drugs do with the body --- is the pharmacodynamics . What the body do with the drug ----- is the pharmacokinetics .

11. BRANCHES OF PHARMACOLOGY 4. Therapeutics : It is a branch of pharmacology that deals with the chemical uses of drugs and treatment with various drugs. 5. Chemotherapy : Chemo – means chemicals and therapy – means treatment It is the study of use of drugs to destroy the invadin organism or microorganism without damaging the host. 6. Posology : It is the branch of pharmacology that deals with the study and dosage of drugs. 7. Metrology : It is the branch of pharmacology which deals with the weights and measurement or quantification of the drugs.

12. BRANCHES OF PHARMACOLOGY 8. Pharmacognosy : It is the branch of pharmacology that deals with sources and physio -chemical properties of the drugs. - Physical properties : such as color, shape, molecular wt., molecular volume, melting and boiling points, density, viscosity, gravity. - Chemical properties : such as pH, pKa , dissociation constant, polarity, electron donation etc. 9. Pharmacogenetics It is the branch of pharmacology that deals with the effects of drugs with reference to the genetic makeup of the specie. In our areas, Quinine – is used as anti-malarial drug but is proved toxin for the African population.

13. BRANCHES OF PHARMACOLOGY 10. Matria Medica : It is an obsolete term now a days. It was applied to the study of all factors relating to drugs including; their origin, preparation, dosage, and clinical usuage of drugs. 11. Toxicology : It is the branch of pharmacology that deals with the adverse effects of any substance. Drug toxicology only deals with the adverse effects of the drugs. Some commonly used terms related to toxicology: Poison: Substance that has deleterious effects for animals and human beings. Toxicants: is the synonym which is used for the poison. Toxin: Any deleterious substance which is produced from the living organisms or microorganism. For example: Phytotoxins – toxins from plants. Mycotoxins - toxins from fungi. Zootoxin – toxins of small animals like scorpion, wasps, and snakes etc. Venoms: Any toxin which is transmitted by biting or sting is called venom e.g. snake venom.

14. DRUGS ACTING ON GIT There are a large number of substances of widely different chemical composition which act in a number of different ways at various sites in the gastrointestinal tract. 1) Sialagogues : The drugs which are used to increase the saliva production. e.g. Pilocarpine , cholinergic drugs 2) Anti- sialagogues : The drugs which are used to decrease the saliva production. e.g. atropine, anticholinergic drugs 3) Stomachics : The drugs which increase the stomach efficiency. e.g. nux vomica , ginger 4) Carminatives : The drugs which are used to expel the gasses from the gastrointestinal tract. e.g. chloroform, beverages, eno 5) Emetics : The drugs which are used to induce vomition . e.g. apomorphine , copper sulphate (small dose)

15. DRUGS ACTING ON GIT 6) Anti-emetics : The drugs which are used to stop or inhibit the vomiting. e.g. largactil (generic name = chlorpromazine), gravinate , marzine , maxalon 7) Antacids : The drugs which are used to reduce the acidity in the stomach. e.g. NaHCO3 (used in ancient time) but it gives rise to; “ Acid Rebound Phenomenon ” It state that when sodium bicarbonate (NaHCO3) is taken as antacids, it produces CO2 in the stomach which stimulate the gastric glands to produce more acids – result into peptic ulcers. Therefore, now a days it is banned to use NaHCO3 as antacids. Other examples of antacids: Mucaine , tricil , bisil , Milk of magnesia, omeprazole 8) Laxatives : The drugs which releive the constipation or evacuate GI contents gently. e.g. MgSO4, Liquid Paraffin.

16. DRUGS ACTING ON GIT 9) Purgatives : The drugs which evacuate the GI contents quickly and can cause diarrhea like condition. E.g. High dose of MgSO4, Castor oil. 10) Cathartics : The drugs that can lead to severe evacuation of GI contents and cause shooting diarrhea like condition. e.g. carton oil 11) Antizymotics : The drugs which are used to check or stop the process of fermentation. e.g. T.T. oil 12) Astringents : The drugs which are used to stop the diarrhea by producing reversible protein precipitation along the inner mucosa of the intestine. e.g. Tannic acid, Rice gravel. 13) Anti- spasmodics The drugs which are used to reduce the spasm in smooth muscles of the intestines. E.g. Hyosine , Buscopan 14) Cholengogues The drugs which are used to increase the bile flow. e.g. Bile salts (like leverage’s etc. )

17. DRUGS ACTING ON URINARY SYSTEM 1) Diuretics : The drugs which increase the urine production. e.g. water, tea, Lasix ( furosemide ), Mannitol , Diamox and K+ salts. 2) Anti diuretics The drugs which decrease the urine production. e.g. ADH (Anti diuretic Hormone) 3) Urinary Sedative: The drugs which relieve irritability of bladder e.g. atropine and hyoscyamus . 4) Urinary Antiseptics: These drugs prevent the multiplication of organisms in the urine e.g. hexamine 5) Urinary Alkalizers /Acidifiers The drugs used to make the urine alkaline e.g Citralka , NaHCO3, acetate, citrates or acidic e.g NH4Cl, ammonium acid phosphate

18. DRUGS ACTING ON CENTRAL NERVOUS SYSTEM (CNS) CNS stimulants : The drugs that can increase the activity of CNS. e.g. caffeine , amphetamine CNS depressants: The drugs which are used to decrease the activity of CNS. e.g. Nicotine, morphine. - The degree of action is different as follows: a) Sedatives : the drugs which are used to sedate or to induce drozziness or lethargy in the animal. e.g. Chloral hydrate, pentobarbitone b) Hypnotics : the drugs which are used to induce a state of sleepiness. e.g. Increased dose of sedatives

19. DRUGS ACTING ON CENTRAL NERVOUS SYSTEM (CNS) 1) Anaesthetics : The drugs which are used to induce anesthesia or to produce a state of unconsciousness. These drugs are classified into two main categories; a) General anesthetics : These drugs are used to produce anesthesia over the entire body of animal. e.g. Gasses – Nitric oxide, Volatile acids – ether, chloroform and Barbiturates. b) Local anesthetics : The drugs which are used to produce a state of unconsciousness over a specific part of the body. e.g. Xylocaine , Lignocaine , Procaine. 2) Narcotics : The drugs that cause the depression of CNS and can lead to drug addiction or drug dependence. E.g. Morphine. These drugs also produce a physical depression.

20. DRUGS ACTING ON CENTRAL NERVOUS SYSTEM (CNS) 3) Tranquilizers : The drugs which are used to reduce the mental tension or anxiety without interference with the normal activity. e.g. Chlorpromazine, promazine derivatives. 4) Analeptics : The drugs that are used to stimulate the depressed respiratory centre. These drugs are also known as “lifesaving drugs”. e.g. leptazole , nikethamide , picrotoxin . 5) Euthenatics : The drugs or techniques used for peaceful death of the animal. e.g. over dose of general anaesthetics , MgSO4, CO2 suffocation, shooting of brain, slaughtering and electric cutter.

21. DRUGS ACTING ON SKIN AND MUCOUS MEMBRANES 1) Emollients : These are inert oily substances used to sooth the irritated skin and mucous membranes. E.g. vegetable oils, waxes, vessiline , paraffin, glycerin 2) Demulcents : The drugs which are applied superficially on the mucous membranes for their soothing effects. E.g. Gum acacia, Gum tragacanth 3) Caustic : Any agent or drug that can destroy the tissue or lead to death of the live tissue. e.g. AgNO3 (1% solution), Antimony CCl4, Glacial acetic acids 4) Counter Irritants : The drugs which are applied on the skin to promote blood circulation of that a area. Or which convert chronic inflammation into acute inflammation. These are categorized into three sub classes. i ) Rubefacients : It is mild form of counter irritants. e.g. Iodex , ventogeno . ii) Blisters : It is the moderate form of counter irritants. e.g. Bin iodine of Hg / Red iodide of Hg. iii) Firing : Affected part is touched with red burning hot iron.