This document provides an introduction and overview of key concepts in pharmacology. It defines pharmacology and divides it into pharmacokinetics and pharmacodynamics. It also defines common terms like drug, medicine, dosage, toxicity, and adverse reactions. The document outlines classifications of drugs based on their mechanism of action, therapeutic use, and chemical composition. It discusses factors that influence adverse drug reactions and ways to prevent such reactions.

1. Pharmacology-I
Course code PMS-614
By Dr. Junaid Athar
Chapter No. 1
Institute of paramedical sciences,
Khyber Medical University Peshawar
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2. Introduction to Pharmacology
Def: Study of substances that interact with living system through chemical process,
especially by binding to regulatory molecules and activating or inhibiting normal
body process.
• Pharmacology is derived from two words; Pharmacon means drugs or medicine
and logos means study
• It has two devisions as follows
• Pharmacokinetics: it means the movement of drugs in the body (absorption,
distribution, biotransformation, and excretion).
• Pharmacodynamics: The mechanism by which the drug exerts its effect. For
example, how aspirin work as analgesic.
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3. Basic definitions
Drug means any chemical substance which exerts a physiological effect on the cell.
Medicine, means any drug substance used to prevent, treat, cure, or diagnose a disease
in proper dose. All medicines are drugs, not all drugs are medicines.
Therapeutics: the branch of medicine that deals with the treatment and cure of diseases
Toxicology: Toxicology is the study of the harmful effects of chemicals and biological
substances on human health
Adverse reaction : A response to a drug which is noxious and unintended
Dose means the amount of medicine taken by a patient
Dosage form means the physical form of the medicines (solids, liquids, gas etc.)
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4. 4

5. Cont…
• Over the counter (OTC) medicine means those medicines for which the
physician prescription is not required. For examples, analgesics.
• Orphan drug: A drug used to treat, prevent, or diagnose an orphan disease. An
orphan disease is a rare disease or condition that affects fewer than people. Less
than 200000 in USA, less than 20000 in Europe.
• Analgesic means those medicines which are used for pain
• Antipyretics means those drugs which are used for fever
• Drug source: it means the origin of drug (natural, semi synthetic, synthetic etc.
natural sources of drug are plants, minerals, animals, and microbes).
• Drug nomenclature: Each drug actually has 3 names. The first is the chemical
name. The second name is the generic. The 3rd name is used by the pharmaceutical
companies. 5

6. Cont…
• Idiosyncratic means unexpected drug reaction
• Teratogenic means harmful effects of drugs on the fetus
• Synergism means when the combination of drugs increases the effects
• Antagonism means when the combination of drugs decreases the effects
• Active ingredient means biologically active substance which produce
effect
• Efficacy means maximum effect that a drug can produce regardless of dose.
• Potency means amount of a drug that is needed to produce a given effect
• Pharmacopoeia: it is a source of drug information. it is an official
publication, containing a list of medicinal drugs with their effects and
directions for their use. BP: British Pharmacopoeia. USP: United States
Pharmacopeia 6

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8. Cont…
• Bioavailability is the degree to which or the proportion of the drug that is
available to the site of action or target tissue to produce the desired effect.
• Half-life (t1/2) is the time taken by the plasma concentration of the drug to
decrease by 50%, or reach half of the original concentration
• Prophylactic agent is any drug that prevents a disease or illness from occurring
• Therapeutic effect : A drug is given to produce a desired effect on the body,
either to treat a disease or to relieve symptoms. This is referred to as a drug’s
therapeutic effect.
• Tolerance is a decrease in the pharmacological response to a drug that occurs with
continued administration
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9. ADVERSE DRUG REACTION
Any noxious change which is
Suspected to be due to a drug
At doses normally used in man
May requires treatment or decrease in dose or
Caution in the future use of the same drug
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10. Continued…
• Incidence of ADR are more in
• Polypharmacy
• Elderly
• Children
• Patient with multiple diseases
• Pregnancy
• Malnourished
• Immunosuppression
• Drug Abusers and addicts
• Develop
• Immediately
or
• Prolonged medication
or
• After stopping. 10

11. GRADING OF SEVERITY OF ADVERSE DRUG
REACTIONS :
Minor : No therapy, antidote or prolongation of
hospitalization is required.
Moderate: Requires change in drug therapy, specific
treatment or prolongs hospital stay.
Severe: Potentially life-threatening, causes permanent
damage or requires intensive medical treatment.
Lethal : Directly or indirectly contributes to death of the
patient. 11

12. CLASSIFICATIONS OF ADR
• A (Augmented)
• B (Bizarre)
• C (Continuous)
• D (Delayed)
• E (Ending Use)
• F (Failure of Efficacy)
• Broadly
• Type- A (Predictable)- Based on pharmacological properties
• Type- B (Non-predictable) – Based on Immunological response
and genetic makeup of person 12

13. TYPE A- AUGMENTED
• These are based on the pharmacological properties of the drug so can be predicted.
• They are common and account for 75% of ADRs
• Dose related and preventable mostly reversible.
Examples:-
• Anticoagulants (e.g., warfarin, heparin) – bleeding
• Anti-hypertensives (e.g.. α1-antagonists) – hypotension
• Anti-diabetics (e.g. insulin) - hypoglycemia
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14. TYPE B- BIZZARE OR UNPREDICTABLE
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• Have no direct relationship to the dose of the drug or the pharmacological
mechanism of drug action.
• Develop on the basis of:
• Immunological reaction on a drug (Allergy)
• Genetic predisposition (Idiosyncratic reactions)
• More serious clinical outcomes with higher mortality and morbidity.
• Mostly require immediate withdrawal of the drug.

15. TYPE C – CHRONIC (CONTINOUS) USE
• They are mostly associated with cumulative-long term exposure
Example:-aspirin ibuprofen naproxen
Analgesic (NSAID)– interstitial nephritis, papillary sclerosis, necrosis
TYPE D – DELAYED
• They manifest themselves with significant delay
imminomodulatory
• Teratogenesis -Thalidomide – Phocomelia (flipper-like fore limbs)
• Mutagenesis/Cancerogenesis
Others:
Tardive dyskinesia – during L-DOPA Parkinson disease treatment
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16. TYPE E – END OF USE
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• Drug withdrawal syndromes and rebound phenomenons
• Example – sudden withdrawal of long term therapy with -blockers
can induce rebound tachycardia and hypertension

17. PREVENTION OF ADVERSE EFFECTS TO DRUGS
• Avoid inappropriate use of drugs .
• Appropriate drug administration (Rational Therapeutics)
• Dose
• Dosage form
• Duration
• Route
• Frequency
• Technique
• Ask for previous history of drug reactions and allergies
• Always suspect ADR when new symptom arises after initiation of treatment. ( No
new drug for new symptom).
• Ask for laboratory findings like serum creatinine etc.
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18. Classification of drugs
•What is drug classification?
• A drug class is a set of medications that have either similar chemical structures,
the same mechanism of action or are used to treat the same disease.
• Drugs have been classified either on the basis;
Chemical composition: β-lactam antibiotic, Benzodiazepine, Steroids
bacterial infection
pencellin anxity
insomnia
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19. Classification based on mechanism of action
• Angiotensin II receptor antagonist: losartan, valsartan
• ACE inhibitor: captopril, ramipril, lisinopril
• Alpha-adrenergic agonist: Phenylephrine, Clonidine
• Beta blockers: Propranolol, Atenolol
• Dopamine agonist:
• Cyclooxygenase inhibitors
• Proton-pump inhibitor: omeprazole, esomeprazole
• Cholinergic:
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20. Classification based on Therapeutic class
• Analgesics: Drug used to relieve pain.
• Antibiotic:
• Anticoagulant
• Antidepressant
• Anticancer
• Antiepileptic
• Antipsychotic
• Antiviral
• Sedative
• Antidiabetic
• Cardiovascular
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21. Contiued…
• An anesthetic or anaesthetic is a drug used to induce anesthesia - in other words,
to result in a temporary loss of sensation or awareness.
• Analgesics: Drug used to relieve pain
• Anthelmintics: a group of antiparasitic drugs that expel parasitic worms
(helminths) and other internal parasites from the body
• An antidote is a drug, chelating substance, or a chemical that counteracts
(neutralizes) the effects of another drug or a poison
• Antimicrobial: these drugs act either to inhibit, kill or retard the growth of
micro-organism
• Anti-inflammatory : the substance or treatment that reduces inflammation or
swelling.
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22. Continued…
• Anticoagulants: these are commonly referred to as blood thinners, are chemical
substances that prevent or reduce coagulation of blood, prolonging the clotting
time.
• Antihistamine: A drug or other compound that inhibits the physiological effects
of histamine, used especially in the treatment of allergies.
• Antacids: An antacid is a substance which neutralizes stomach acidity and is used
to relieve heartburn, indigestion or an upset stomach.
• Anticonvulsants : they are a diverse group of pharmacological agents used in the
treatment of epileptic seizures
• Anti-diarrhoeal: these drugs are used for diarrhea
• Antitussive: Antitussives are medicines that suppress coughing, also known as
cough suppressants.
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23. Continued…
• Anti asthmatics: Drug which provide symptomatic relief of asthmatic attack by
relaxing the smooth muscle of the bronchioles
• Androgens: An androgen is any natural or synthetic steroid hormone which
regulates the development and maintenance of male characteristics
• Antiseptic: Antiseptics are antimicrobial substances which inhibit the growth
of micro organism
• Anti fungal/ antimycotic : It is a pharmaceutical fungicide or fungistatic used to
treat and prevent growth of fungal infection.
• Antispasmodic: An antispasmodic is a pharmaceutical drug or other agent that
suppresses muscle spasms
• Antiemetic: An antiemetic is a drug that is effective against vomiting and nausea.
• Anti tubercular: Specific drug is used in treatment of Tuberculosis (TB) 23

24. Continued…
• Antirheumatic: Drug is used to teat rheumatism
• Bronchodilators: A bronchodilator is a substance that dilates the bronchi and
bronchioles, decreasing resistance in the respiratory airway and increasing airflow
to the lungs.
• Coagulants: An agent that produces coagulation (Coagulation is a complex
process by which blood forms clots).
• Carminatives: A carminative is a herb or preparation intended to either prevent
formation of gas in the gastrointestinal tract or facilitate the expulsion of said gas,
thereby combatting flatulence.
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25. Legal classification
• For the UK legal classification, see Drugs controlled by the UK Misuse of Drugs
Act
• For the US legal classification, see Controlled Substances Act § Schedules of
controlled substances
• Pregnancy category is defined using a variety of systems by different jurisdiction
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26. Any Question?

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