Pharmacology

Pharmacology Principles

1. Introduction to Pharmacology Pharmacology is the study of the action of drugs on living tissues or organisms and how those drugs help to diagnose, treat, cure & prevent disease or correct pathophysiology of living tissues or organisms. Pharmacology is derived from two Greek words: Pharmakon means drug & Logos means study. Clinical Pharmacology is the study of drugs in humans. It includes the pharmacokinetic & pharmacodynamic studies of drugs in humans. It is useful for rational prescription of drugs. Drug is defined as an agent used for the diagnosis, mitigation, treatment, cure or prevention of diseases in humans & animals.

2. Pharmacology has two main subdivisions: Pharmacokinetics (what body does to drugs?) A bsorption D istribution M etabolism E limination Pharmacokinetics is the study of process by which a drug is absorbed, distributed, metabolized & eliminated by the body. Pharmacodynamics (what drug does to body?) Drug + Receptor = Effect Pharmacodynamics is the study of interaction of drug and receptors responsible for the action in the body.

3. Chemotherapy : it is the treatment of systemic infection or malignancy with the effects of drugs on microorganisms, parasites, living & multiplying in a living organism without or minimum effects on host cells. Toxicology: it is the study of poisonous effects of drugs or other chemicals with emphasis on detection, prevention & treatment of poisoning. Bioavailability: it is the fraction of an administered drug or other chemicals that reaches the blood stream. When the drug is given i.v . the bioavailability is 100%. Pharmacotherapeutics : it is the study of the use of drugs to treat or prevent disease. It can be preventive, palliative or restorative.

4. Drug Nomenclature It is the naming of the drugs. Generally a single drug is given 3 names. Each name is used in different area of drug industry or clinical practice. Chemical Name e.g : N-(4-hydroxyphenyl) acetamide Generic Name e.g : Paracetamol Brand Name e.g : Phenocet Chemical Name Generic Name Brand Name N-(2-[[[5[( dimethylamino )methyl]-2-furanyl]methyl] thio ]ethyl]-N’-methyl-2-nitro-1,1-Etenediamine Ranitidine Aciloc N-(4-Nitro-2-phenoxyphenyl) methane sulfonamide Nimesulide Nims

5. Chemical Names It is the name given to the molecular formula of drugs by IUPAC or chemical body. Chemical name represents the chemical elements present in the compound. The chemical name is important to chemists, pharmacists or researcher who synthesize drugs. Chemical name of Paracetamol is N-(4-hydroxyphenyl) acetamide . Generic Names It is the official name of the drug and accepted universally. Generic name appears on all drug labels and listed in official books such as Formulary, Pharmacopoeia & Physicians Desk Reference (PDR). Generic name of Aciloc is Ranitidine.

6. Brand Name It is the name given to a drug by the company which manufactures drug. Each company has their own brand name & have copyright©. Brand name for Ranitidine is Aciloc by Cadila .

7. Drug orders Routine order It is an ongoing order e.g:Lasix ( Furosemide ) 40 mg po od One time order It is single dose e.g : Demerol( pethidine )50mg+vistaril( hydroxyzine ) 25mg i.m . PRN When required e.g : Advil(Ibuprofen) 600mg po PRN Stat Immidiately e.g : benadryl 50 mg po stat

8. Essential Drug List (EDL) Essential drugs are all those drugs that satisfy the primary health care needs of the population. EDL is needed to ensure safety, efficacy & quality of drugs. It ensures availability & accessibility of essential medicines to all citizens. It promotes the rational use of drugs by prescriber, dispenser & patient. It helps to minimize unwanted or diverse effects of drugs. Essential drugs should be available at all times, in adequate amounts, in appropriate dosage forms & at affordable price.

9. EDL concept was first initiated by WHO in 1977. EDL was first published in Nepal by DDA in 1986 and now it has fifth revision in 2016. GON provides 70 types of medicines for communicable and non-communicable diseases free of cost from all district hospitals throughout the country. Primary Health Care centres provides 58 types of medicines and health posts provides 35 types of medicines to patients without any charge.

10. S.N. Generic Name Dosage Form 1.Anaesthetics Ketamine inj 50mg/ml 2.NSAIDS, DMARDS Ibuprofen tab 200mg,400mg 3.Antiallergics chlorpheniramine tab 4mg 4 Antidotes Activated charcoal Powder, slurry in sorbitol 5. Antiepileptics /Anticonvulsants Carbamazepine tab 100mg 6. Antiinfectives Albendazole tab 400mg 7.Antimigraine Ergotamine tab 1 mg 8.Antineoplastic Cisplatin Powder for inj 10 mg 9.Antiparkinson Levodopa + Carbidopa tab 100mg+10mg 10.Drug affecting blood Warfarin tab 5mg

11. Rational Use Of Drugs Rational use of drugs ensures that patients receive medicines appropriate to their clinical needs, in proper doses, for adequate period of time & at affordable cost to patients. Five Rights of Drug Administration: Right patient Right drug Right dose Right time Right route

12. Drug Categories: Schedule A ( क ) Narcotic & Poisonous drugs are included in this category. Prescription is required & record should be kept for such drugs. e.g : morphine, pethidine , methotrexate , vincristine , chlorambucil , etc Schedule B ( ख ) Prescription drugs are included in this category. E.g : amoxicillin, cloxacillin , gentamicin , antirabies serum, etc Schedule C ( ग ) Over The Counter(OTC) drugs are included in this category. These drugs can be available to patients without prescription. They are are categorized as safe. e.g : Paracetamol , vitamin supplements, metronidazole , etc

13. Route of Administration Primary Dosage Forms