1.-NOMENCLATURE-AND-CLASSIFICATION-OF-DRUGS

NOMENCLATURE AND CLASSIFICATION OF DRUGS

NOMENCLATURE OF DRUGS

• The term drug nomenclature refers to the various names that can identify a drug.

• Drugs are known by three different names:

  1. Chemical Name

  2. Non-Proprietary Name

  3. Proprietary Name

CHEMICAL NAME

• Given when a New Chemical Entity (NCE) is developed.

• Complies with the rules established by the International Union of Pure and Applied Chemistry.

• Useful for chemists, detailing the precise arrangement of atoms and groups within the molecule.

• Not generally used in clinical or marketing contexts.

NON PROPRIETARY NAME

• A concise name assigned to a drug not subject to proprietary rights.

• Commonly used in discussions and textbooks.

• Two classes of non-proprietary names:

  1. Approved Name

  2. Official Name

Approved Name

• Assigned by organizations like the United States Adopted Name Council (USAN) and British Approved Name (BAN) post-introduction.

• Often referred to as Generic Name, though this can refer to a class of drugs (e.g., Sulphonamide, Penicillin).

Official Name

• The name approved by the National Pharmacopeia Commission, as included in the Pharmacopeia.

• Must be identical to the approved name.

PROPRIETARY NAME

• Assigned by the pharmaceutical company marketing the drug.

• Each drug can have multiple proprietary names from different manufacturers.

• Written with an initial capital letter and often accompanied by a superscript ®.

• Clinicians typically refer to drugs by their proprietary names.

EXAMPLE: Paracetamol

• CHEMICAL NAME: N-(4-hydroxyphenyl)acetamide.

• NON-PROPRIETARY NAME:

  • Approved Name (BAN): paracetamol

  • USAN: acetaminophen

  • Official Name: Acetaminophen

• PROPRIETARY NAME: Panadol, Calpol, Tempra, Biogesic

CLASSIFICATION OF DRUGS

• Classification is crucial for reducing thousands of drugs to manageable groups.

• No uniform classification system exists, as it varies based on context (chemist, pharmacologist, pharmacist, clinician).

Classification Methods

1. Chemical Nature

2. Source

3. Target Organ/Site of Action

4. Mode of Action

5. Therapeutic Uses

6. Physiological System

7. Physical Effects

1. Classification Based On Chemical Nature

• Inorganic Drugs:

  • Metals and their Salts: (e.g., Ferrous Sulphate, Zinc Sulphate, Magnesium Sulphate)

  • Non-Metals: (e.g., Sulphur)

• Organic Drugs:

  • Alkaloids: (e.g., atropine, morphine, strychnine)

  • Glycosides: (e.g., digitoxin, digoxin)

  • Proteins: (e.g., insulin, oxytocin)

  • Esters, Amides, Alcohols, Glycerides.

2. Classification Based On Source

• Natural Source:

  • Plants:

    • Morphine: derived from opium poppy

    • Atropine: synthesized from Atropa belladonna

    • Digoxin: extracted from woolly foxglove leaves

  • Animals:

    • Insulin: originally from cows and pigs’ pancreas

  • Microorganisms:

    • Penicillin: derived from Penicillium mold

  • Minerals:

    • Sodium Chloride: pharmaceutical-grade salt

• Synthetic Source:

  • Sulphonamide: man-made antibacterial drugs

  • Procaine: local anesthetic

• Semi-Synthetic Source:

  • Amoxicillin: enhanced penicillin antibiotic

  • Ampicillin: broad-spectrum penicillin

  • Doxycycline: semi-synthetic tetracycline derived from Streptomyces

• Bio-Synthetic Source:

  • Recombinant Human Erythropoietin: biopharmaceutical for anemia treatment

  • Recombinant Bovine Somatotropin: from genetically modified E. coli

3. Classification Based On Target Organ/Site

• CNS Drugs: Diazepam, Phenobarbitone

• Respiratory Drugs: Bromhexaine

• CVS Drugs: Digitoxin, Digoxin

• GIT Drugs: Omeprazole, Kaoline, Sulphadimidine

• Urinary System Drugs: Magnesium Sulphate, Lasix

• Reproductive Drugs: Oxytocin, Estrogen

4. Classification Based On Mode Of Action

• Bacterial Cell Wall Synthesis Inhibitors: Penicillin

• Bacterial Protein Synthesis Inhibitors: Tetracycline

• Calcium Channel Blockers: Verapamil, Nifedipine

5. Classification Based On Therapeutic Use

• Antimicrobials/Antibacterials: Penicillin, Streptomycin, Quinolones, Macrolides

• Antihypertensives: Amlodipine, Hydralazine, Enalapril

• Antidiarrheals: Loperamide

• Antiemetics: Domperidone, Meclizine, Metoclopramide

6. Classification Based On Physiological System

• Sympathomimetics: Adrenaline, Noradrenaline

• Parasympathomimetics: Carbachol, Pilocarpine, Neostigmine

• Neuromuscular Blockers: Suxamethonium, Gallamine

7. Classification Based On Physical Effects

• Emollients: Soothing agents (e.g., Lanolin, Vaseline)

• Caustics: Things that can destroy by chemical action (e.g., Silver Nitrate)

• Demulcents: Relieve inflammation (e.g., Zinc Oxide, Tannic Acid)

LEGAL CLASSIFICATION

• Prescription: Requires an order from licensed health practitioners (e.g., physicians, pharmacists).

• Non-Prescription: Over-the-counter (OTC) drugs available without a prescription.

ROLE OF RADIOLOGIC TECHNOLOGISTS

• Broad knowledge of drugs (classification, actions, interactions, reactions) is expected for RTs.

• Skills in drug administration help in various clinical scenarios.

Drug knowledge is key to enhancing patient care and maintaining professional competency.