1. introduction, route of administration
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Transcript of 1. introduction, route of administration
Introduction to Pharmacology
Dr.Arul AmuthanLecturer in Pharmacology
Melaka Manipal Medical College Manipal University
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pharmacology - drug study
What is Pharmacology ?
Science that deals with the effects of drugs on living
system.
Sources, biological effects, therapeutic uses,
adverse effects and interactions of drugs2
What is drug ?
Substance that modify the physiological systems or
pathological state for the benefit of the recipient.
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Pharmacokinetics:
What the body does to the drug
Absorption, Distribution, Metabolism, Excretion
[ADME]
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Pharmacodynamics:
What the drug does to the body
Drug’s mechanism of action
Pharmacological effects of drug
Adverse effects of drugs
Drug interaction
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Pharmacotherapeutics:
Application of pharmacological information together
with disease knowledge for prevention and cure
Selection of drug, dose, duration of treatment
Toxicology:
Harmful effects of drug
Detection, prevention, treatment of poisoning
Study of adverse effects
Clinical pharmacology:
Scientific study of drugs in man
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P.kinetic/dynamic investigation in healthy and patients
Evaluation of efficacy and safety, adverse effects
Comparative trails, Surveillance
SOURCES OF DRUGS
I. Natural sources
II. Semisynthetic sources
III. Synthetic sources
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Plants:
Morphine, codeine, atropine, quinine, digoxin
Animals: insulin, thyroxine
Microorganisms: penicillin, streptomycin
Minerals: iron, calcium, zinc
I. Natural sources:
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II Semisynthetic sources:
Ampicillin, Amoxicillin (semisynthetic penicillins)
Diacetyl morphine
III.Synthetic sources:
paracetamol, erythromycin, pethidine
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Drug nomenclature:
Chemical name - Generic name - Trade name
3.Trade name: (brand, proprietary name)
Given by a pharmaceutical company
Sole property of the pharmaceutical company
A drug may have many proprietary names
Same company – different name in different countries
Prescription, over-the-counter drugs
Ecospirin, Disprin (for aspirin)
Crocin, Calpal (for paracetamol)12
2.Generic name:
Assigned by - United States Adopted Name (USAN) council
British Approved Name (BAN) council
Used uniformly in all countries
After the drug included in pharmacopeia - official name
Aspirin, paracetamol
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1. Chemical name:
Is the name of chemical compound present in a drug
Acetyl salicylic acid, Acetaminophen
Not suitable for prescribing
Number is given before name is framed (Eg: INR00439)
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Sources of drug information
Pharmacopeia:
Book containing names of officially approved drugs
with their physical and chemical characteristics.
Eg: Indian Pharmacopoeia (IP)
BP, USP
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Non-official references:
Physicians’ Drug Reference (PDR)
Dental Drug Reference (Mosby)
Monthly Index of Medical Specialists (MIMS)
Medical journals:
The Malaysian Journal of Medical Sciences
Medical Journal of Malaysia, BMJ
US Food and Drug Administration (FDA): www.fda.gov16
1. Enteral route: oral, sublingual, rectal routes
2. Parenteral routes: intradermal, subcutaneous,
intramuscular, intravenous, intra-arterial, intrathecal
3. Topical: skin and mucous membrane
4. Others: transdermal, inhalational
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Route of drug administration
Oral route: Advantages:
Safe, convenient for long use
Painless, self administered
Disadvantages:
Slow onset of action (not used in emergency)
Not suitable - in diarrhoea/vomiting/unconscious cases
- unpalatable/irritant drugs, unabsorbed drug
Aspirin, paracetamol, ibuprofen18
Sublingual: Advantages:
Quick onset of action, bypass first pass metabolism
Self administered, terminated by spiting out
Disadvantages:
In children
Bad smell & lipid insoluble drugs
Nitroglycerin for angina
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Advantages:
Unpleasant drugs
In vomiting, unconscious cases
Disadvantages:
Inconvenient, embarrassing
Causes rectal inflammation
Prednisolone for ulcerative colitis
Ergotamine, diazepam for systemic effect20
Enema (fluid)
suppositories (tablets)
Rectal:
Parenteral routes & site:
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Intradermal:
Disadvantages:
Painful, no self administration
small amount of drug is administered
Eg: BCG vaccine, drug sensitivity tests
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Subcutaneous:
Advantages:
Self administration is possible
Depot can be inserted into sc
Disadvantages:
Slow absorption, not useful in emergency
Suitable only for non-irritant drugs
Eg: Insulin, adrenaline
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Intramuscular: Advantages:Rapid absorptionDepot injections10 ml can be given at a timeUseful in vomiting, diarrhea, unconscious patientsBypass first pass metabolism
Disadvantages:Sterilization requiredPainful, no self administrationInjury to nerve, cause abscess
Eg: gentamicin, streptomycin, kanamycin 24
Intravenous: Advantages:
Directly reaches blood
Bypass first pass metabolism, 100% bioavailability
Emergency – fast onset of action
Large volume infused – iv fluids
High irritant drugs is given
Useful in vomiting, diarrhea, unconscious patients
Eg: furosemide, diazepam
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Intravenous: Disadvantages:
Once administered, can’t be stopped
Painful, no self medication
Strict aseptic precautions
Extravasation causes tissue necrosis
Causes thrombophlebitis
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Topical: (skin and mucous membrane)
Advantages:
More convenient, encouraging to patient
Efficiently delivered to local lesion areas
Disadvantages:
Local irritation, dermatitis
silver sulfadiazine ointment, diclofenac gel
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Transdermal/Transcutaneous:
Adhesive patch
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Advantages:
Self administered, better patient compliance
Prolonged duration of action
Less systemic side effect
Disadvantages:
Expensive
Local irritation causes dermatitis, itching
Patch may fall off unnoticed
scopolamine, nitroglycerine, oestrogen29
Inhalational:
Volatile liquids and gases are given for systemic effects
Advantages:
Absorption through alveoli, rapid onset of action
Less dose is enough, so less systemic toxicity
Amount of drug can be regulated
Disadvantages:
Irritation causes bronchospasm and high secretion
General anaesthetics – nitrous oxide, ether, halothane30
Drug into subarachnoid space - Intrathecal
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Intrathecal – lignocaine, amphotericin
Intra articular – hydrocortisone
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