UNIT-I

Introduction to Pharmacology
By
Ashok Kumar
 Objectives
• Discuss the terminologies related to pharmacology
• Discuss the history of pharmacology briefly
• Identify the purposes of medication
• Identify the source of medication
• Discuss the classification of drugs
• Describe the three type of drug supply system.
• Discuss the drugs standards and legislation.
• Identify resource to collect and utilize drug information.
• Learn to prepare drugs cards
 Discuss the terminologies related to pharmacology

• Pharmacology: is a branch of science which concerned with the origin, nature,

chemistry, effects, and uses of drugs. This includes understanding the interactions
between chemical substances and living systems.

• Drug: According to the WHO, a drug is any substance or product that is used or
intended to be used to modify or explore physiological systems or pathological
states for the benefit of the recipient.
 Cont…
• Pharmacokinetics: This refers to the movement of drugs within the body and
includes four main processes: absorption, distribution, metabolism, and
excretion. Understanding pharmacokinetics is crucial for determining the
correct dosage and timing of medication administration​​.

• Pharmacodynamics: This involves the study of the physiological and

biochemical effects of drugs and their mechanisms of action. It explores how
drugs affect the body, including the relationship between drug concentration and
effect​​.
 Cont….
• Bioavailability: This is the proportion of a drug that enters the circulation when
introduced into the body and is able to have an active effect. It is a key factor in
determining the correct dosage of a drug​.

• Half-life: The half-life of a drug is the time it takes for the concentration of the
drug in the bloodstream to reduce by half. This concept helps in understanding
the duration of action of the drug and planning the dosing schedule​
 Cont…
• Agonist vs. Antagonist: An agonist is a substance that activates a receptor to
produce a biological response, while an antagonist blocks or dampens the action
of a receptor. These terms are crucial in understanding how different drugs
interact with cellular receptors​​.

• Therapeutic Index: This is the ratio between the toxic dose and the therapeutic
dose of a drug. A higher therapeutic index indicates a greater margin of safety
for the drug​.
Cont…
• Side Effects vs. Adverse Effects: Side effects are unwanted but often
predictable effects of a drug, whereas adverse effects are harmful and
undesired effects that can lead to significant health risks​​.

• First-Pass Effect: This refers to the initial metabolism in the liver of a

drug taken orally before it reaches systemic circulation, reducing the
bioavailability of the active drug​.
 Cont…
• Drug Interactions: These occur when the effects of one drug are altered by the
presence of another drug, food, or substance. Understanding drug interactions
is vital for avoiding potential adverse effects and ensuring drug efficacy.

• Absorption: The process by which a drug enters the bloodstream from its site of
administration. This can occur via various routes such as oral, intravenous,
intramuscular, subcutaneous, and others.

• Distribution: The dispersion or dissemination of substances throughout the

fluids and tissues of the body. After a drug is absorbed, it is distributed to the
tissues where it exerts its pharmacological effects.
 Cont…
• Cumulative Effect: The condition in which repeated administration of a drug
may produce effects that are more pronounced than those produced by the first
dose. This often occurs when the drug is taken more frequently than the body
can eliminate it.

• Tolerance: A state where increasing doses of a drug are required to achieve the
same therapeutic effect. Tolerance can develop with repeated use of certain
drugs, particularly those affecting the central nervous system.
 Cont..
• Dependence: A physical or psychological need for a drug. Physical dependence
is characterized by withdrawal symptoms when the drug is not taken, while
psychological dependence is characterized by a perceived need for the drug.

• Synergism: When the combined effect of two drugs is greater than the sum of
their individual effects. This can be used therapeutically to enhance drug effects.
 Cont…
• Potency: A measure of the drug's strength, indicating the amount needed to
produce a certain effect.

• Efficacy: The ability of a drug to achieve its desired therapeutic effect,

indicating the maximum effect achievable.

• Shelf Life: The duration for which a drug or product remains effective and safe
for use.
• Hypersensitivity: An exaggerated response by the immune system to a drug.
 Cont…
• Indications:
The reason for administering a medication or performing a treatment.
• Contraindication:
Factors that prevents the use of a medication or treatment ( e.g.. Allergies )
• Effects (therapeutic effect):
The desired results of administration of a medication.
Cont…
•Duration
•The time a drug concentration is sufficient to elicit a therapeutic
response.
•Onset
•The time it takes for the drug to elicit a therapeutic response .
Discuss the history of pharmacology briefly
• Student assignment
 Identify the purposes of medication
• Curative
• Purpose: To cure a disease or eliminate an infection.
• Examples: Antibiotics to treat bacterial infections, antifungals for fungal
infections, and antivirals for viral infections.
• Preventive (Prophylactic)
• Purpose: To prevent the occurrence of a disease or condition.
• Examples: Vaccines to prevent diseases like influenza and measles,
anticoagulants to prevent blood clots, and statins to prevent heart disease in at-
risk patients.
 Cont…
• Diagnostic
• Purpose: To aid in the diagnosis of a condition.
• Examples: Contrast dyes used in imaging procedures, radiopharmaceuticals for
nuclear medicine scans, and glucose tolerance tests for diagnosing diabetes.
• Palliative
• Purpose: To relieve symptoms and improve quality of life without curing the
underlying disease.
• Examples: Analgesics for pain relief, antiemetics for nausea, and sedatives for
anxiety.
 Cont…
• Supportive
• Purpose: To support bodily functions while the patient recovers from illness or
injury.
• Examples: Fluids and electrolytes for dehydration, blood products for anemia,
and nutritional supplements for malnutrition.
• Restorative
• Purpose: To help the body return to its normal state.
• Examples: Hormone replacement therapy, vitamins and minerals for
deficiencies, and physical therapy medications.
 Cont…
• Substitutive
• Purpose: To replace missing or deficient substances in the body.
• Examples: Insulin for diabetes, thyroid hormone for hypothyroidism, and iron
supplements for iron-deficiency anemia.
• Chemotherapeutic
• Purpose: To target and kill or inhibit the growth of cancer cells.
• Examples: Chemotherapy drugs for cancer treatment, antineoplastic agents,
and targeted therapy drugs.
 Cont…
• Adjunctive
• Purpose: To be used in addition to the primary treatment to enhance its
effectiveness.
• Examples: Using antihistamines along with epinephrine in an allergic reaction,
or using antiemetics alongside chemotherapy to reduce nausea.
• Psychoactive
• Purpose: To affect the mind, emotions, and behavior.
• Examples: Antidepressants for depression, antipsychotics for schizophrenia, and
anxiolytics for anxiety disorders.
 Identify the source of medication
• Natural Sources
1.Plants (Botanical)
1. Examples:
1.Digitalis from foxglove plant for heart conditions
2.Morphine from opium poppy for pain relief
3.Quinine from cinchona bark for treating malaria
• 2.Animals (Zoological)
• Examples:
• Insulin from pancreatic tissue of pigs or cattle (historically; now mostly recombinant DNA
technology)
• Heparin from pig intestines or cow lungs for anticoagulation
• Hormones such as estrogen from pregnant mare urine (historically)
Cont…

•3.Minerals
•Examples:
•Iron supplements from ferrous sulfate for treating anemia
•Magnesium sulfate for treating preeclampsia and as a laxative
•Zinc oxide for skin protection and wound healing
• 4.Microorganisms
•Examples:
•Antibiotics like penicillin from Penicillium mold
•Streptomycin from soil bacteria Streptomyces griseus
•Cyclosporine from the fungus Tolypocladium inflatum for immunosuppression
 Cont…
• Synthetic Sources
1.Chemical Synthesis
1.Examples:
1.Aspirin synthesized from salicylic acid
2.Sulfa drugs for bacterial infections
3.Antihypertensives like beta-blockers
2.Biotechnology (Recombinant DNA Technology)
1.Examples:
1.Human insulin produced by genetically modified bacteria (E. coli)
2.Monoclonal antibodies for various cancers and autoimmune diseases
3.Growth hormones and erythropoietin for growth deficiencies and anemia
 Cont…

• Semi-Synthetic Sources
• Definition: Drugs that are chemically modified derivatives of
natural compounds to enhance their efficacy, reduce side
effects, or improve delivery.
• Examples:
• Semi-synthetic penicillins like amoxicillin
• Hydromorphone derived from morphine
• Etoposide from podophyllotoxin for cancer treatment
Cont…
• Modern Advanced Techniques
1.Genetic Engineering
1.Examples:
1.Gene therapy products for treating genetic disorders
2.CRISPR-based therapies for editing genes to correct mutations
2.Nanotechnology
1.Examples:
1.Nanoparticles for targeted drug delivery in cancer treatment
2.Liposomal formulations for improving the delivery and efficacy of drugs
like doxorubicin
 Discuss the classification of drugs

• The classification of drugs is typically organized based on several criteria,

• Therapeutic use,
• Mechanism of action,
• Chemical structure,
• Legal classification.
 Therapeutic Use
• Analgesics: Medications used to relieve pain.
• Examples: Morphine, acetaminophen, ibuprofen.
• Antibiotics: Medications used to treat bacterial infections.
• Examples: Penicillin, amoxicillin, ciprofloxacin.
• Antihypertensives: Medications used to lower blood pressure.
• Examples: Lisinopril, amlodipine, metoprolol.
• Antidepressants: Medications used to treat depression.
• Examples: Fluoxetine, sertraline, amitriptyline.
• Antidiabetics: Medications used to treat diabetes.
• Examples: Insulin, metformin, glipizide.
Mechanism of Action
• Beta-Blockers: Medications that block beta-adrenergic receptors, reducing
blood pressure and heart rate.
• Examples: Propranolol, metoprolol, atenolol.
• Calcium Channel Blockers: Medications that inhibit the entry of calcium into
heart and smooth muscle cells, reducing blood pressure.
• Examples: Amlodipine, diltiazem, verapamil.
• Selective Serotonin Reuptake Inhibitors (SSRIs): Medications that increase
serotonin levels in the brain by inhibiting its reuptake.
• Examples: Fluoxetine, sertraline, citalopram.
• Proton Pump Inhibitors (PPIs): Medications that reduce stomach acid
production by inhibiting the proton pump in gastric parietal cells.
• Examples: Omeprazole, esomeprazole, pantoprazole.
Chemical Structure
• Benzodiazepines: A class of drugs with a specific chemical structure used
primarily as anxiolytics, sedatives, and muscle relaxants.
• Examples: Diazepam, lorazepam, alprazolam.
• Opioids: A class of drugs derived from opium or synthetic analogs used
primarily for pain relief.
• Examples: Morphine, oxycodone, fentanyl.
• Sulfonamides: A group of antimicrobials containing a sulfonamide group.
• Examples: Sulfamethoxazole, sulfisoxazole.
Legal Classification
• Prescription Drugs: Medications that require a prescription from a healthcare
provider.
• Examples: Antibiotics, antihypertensives, antidepressants.
• Over-The-Counter (OTC) Drugs: Medications that can be purchased without a
prescription.
• Examples: Acetaminophen, ibuprofen, loratadine.
• Controlled Substances: Drugs that are regulated by law due to their potential
for abuse and dependence.
• Schedule I: No accepted medical use, high potential for abuse (e.g., heroin).
• Schedule II: High potential for abuse, accepted medical use with severe restrictions (e.g.,
morphine).
• Schedule III-V: Decreasing potential for abuse, accepted medical use (e.g., codeine,
benzodiazepines).
Route of Administration
• Oral Medications: Drugs taken by mouth.
• Examples: Tablets, Syrup, suspension, Shect.
• Injectable Medications: Drugs administered via injection (intravenous,
intramuscular, subcutaneous).
• Examples: Injection form, Fluid.
• Topical Medications: Drugs applied to the skin or mucous membranes.
• Examples: Hydrocortisone cream, nitroglycerin patch, antibiotic ointments
spray.
• Inhalation Medications: Drugs administered through the respiratory tract.
• Examples: Albuterol, fluticasone, ipratropium.(Solutation, nasal spray,
Inhalor)
Pregnancy Risk Categories (Old FDA
Classification)
• Category A: Controlled studies show no risk.
• Examples: Folic acid, levothyroxine.
• Category B: No evidence of risk in humans, but studies in animals.
• Examples: Amoxicillin, acetaminophen.
• Category C: Risk cannot be ruled out.
• Examples: Fluoroquinolones, SSRIs.
• Category D: Positive evidence of risk.
• Examples: Phenytoin, lithium.
• Category X: Contraindicated in pregnancy.
• Examples: Isotretinoin, thalidomide.
 Describe the three type of drug supply system.

• Floor Stock System

• Description: In the floor stock system, medications are kept in bulk quantities in
a central location, usually in a medication room or on the nursing unit.

• Individual Prescription System

• Description: Medications are dispensed by the pharmacy in individual, labeled

containers for each patient based on the physician's prescription. Each container
typically contains a supply for a specific period (e.g., a 24-hour or 7-day supply).
 Unit Dose System

• The unit dose system involves dispensing medications in single-dose packages

for individual patients. Each dose is labeled with the drug name, dose, and
expiration date.
 Discuss the drugs standards and legislation
• Drug Standards
1.Pharmacopeias and Formularies:
1. United States Pharmacopeia (USP): Establishes standards for the identity, strength,
quality, and purity of medicines.
2. National Formulary (NF): Focuses on excipients, drug delivery systems, and other
inactive ingredients.
Cont….
•Good Manufacturing Practices (GMP):
•Ensures that products are consistently produced and controlled according to
quality standards.
•Covers all aspects of production from the starting materials, premises, and
equipment to the training and personal hygiene of staff.

•International Standards:

•International Conference on Harmonisation (ICH): Provides guidelines to

ensure safe, effective, and high-quality medicines.
•World Health Organization (WHO): Establishes global standards and norms.
 Drug Legislation
1.Historical Context:
1.Pure Food and Drug Act (1906): One of the first laws to regulate drug
quality and labeling.
2.Food, Drug, and Cosmetic Act (1938): Required drug safety proof before
marketing.
2.Regulatory Agencies:
1.Food and Drug Administration (FDA): Governs drug approval,
marketing, and post-marketing surveillance in the U.S.
2.European Medicines Agency (EMA): Regulates drugs in the European
Union.
 Cont….
•Approval Process:
•Investigational New Drug (IND) Application: Permission to start clinical
trials.
•New Drug Application (NDA): Detailed data submission for marketing
approval.
•Abbreviated New Drug Application (ANDA): For generic drug approval.
•Drug Schedules and Controlled Substances:
•Controlled Substances Act (CSA): Categorizes drugs into schedules based on
potential for abuse and medical use.
•Schedule I-V: From highest abuse potential (I) to lowest (V).
 Cont…
•Prescription and Over-the-Counter (OTC) Medications:
•Distinguishes between drugs that require medical supervision and those that
can be used safely without it.
•Patient Safety and Pharmacovigilance:
•MedWatch: FDA's system for reporting adverse effects and safety issues.
•Ongoing monitoring of drug effects and side effects.
Identify resource to collect and utilize drug information
• Drug Information Resources
1.Pharmacopeias and Formularies:
1.United States Pharmacopeia (USP)
2.British National Formulary (BNF)
3.European Pharmacopoeia
2.Drug Reference Books:
1.Physicians' Desk Reference (PDR)
2.Drug Information Handbook
3.Martindale: The Complete Drug Reference
 Cont…
•Electronic Databases:
•Micromedex
•Lexicomp
•Epocrates
•Clinical Pharmacology
•Government and Regulatory Websites:
•Food and Drug Administration (FDA)
•National Institutes of Health (NIH)
•Centers for Disease Control and Prevention (CDC)
•World Health Organization (WHO)
Cont…
•Peer-Reviewed Journals and Articles:
•Journal of Clinical Pharmacology
•British Journal of Pharmacology
•American Journal of Health-System Pharmacy
•Professional Organizations:
•American Society of Health-System Pharmacists (ASHP)
•American Pharmacists Association (APhA)
•International Pharmaceutical Federation (FIP)
Utilizing Drug Information
1.Drug Databases and Software:
1.Use comprehensive drug databases like Micromedex and Lexicomp for
up-to-date drug information.
2.Epocrates and Clinical Pharmacology offer mobile apps for easy access
to drug data.
2.Government Resources:
1.FDA's Drugs@FDA database provides information on approved drugs.
2.MedlinePlus offers patient-friendly drug information.
3.Professional Journals:
1.Regularly review current issues of journals such as the Journal of
Clinical Pharmacology for the latest research and updates on drug
therapy.
Cont…
1.Continuing Education:
1.Participate in continuing education programs and workshops offered by
organizations like ASHP and APhA.
2.Institutional Resources:
1.Hospitals and healthcare institutions often have subscriptions to drug
information databases and libraries of reference books.

• These resources help nurses stay informed about drug properties, indications,
contraindications, side effects, and interactions, ensuring safe and effective
patient care.
 Learn to prepare drugs cards
• The cards are essential tools for nursing students and professionals to quickly
reference important drug information.

• Components of a Drug Card

1.Drug Name:
1.Generic Name: The standard name of the drug.
2.Brand Name(s): Common commercial names.
2.Classification:
1.Therapeutic class (e.g., antihypertensive, antibiotic).
Cont…
•Mechanism of Action:
•How the drug works in the body to achieve its effect.
•Indications:
•Conditions or diseases for which the drug is prescribed.
•Dosage and Administration:
•Typical dosages for different conditions.
•Routes of administration (e.g., oral, intravenous).
•Contraindications:
•Conditions or factors that make the use of the drug undesirable.
•Side Effects:
•Common and serious adverse effects.
Cont…

•Interactions:
•Drugs, foods, or activities that can interact with the drug.
•Nursing Considerations:
•Important points for nurses to monitor.
•Patient education tips.
•Monitoring Parameters:
•Vital signs, lab tests, or symptoms to check for efficacy and safety.
Example of a Drug Card
• Here is an example format for creating a drug card:
• Drug Name:
• Generic: Metformin
• Brand: Glucophage
• Classification:
• Antidiabetic agent
• Mechanism of Action:
• Decreases hepatic glucose production, decreases intestinal absorption of
glucose, and improves insulin sensitivity.
Cont…
• Indications:
• Type 2 Diabetes Mellitus
• Dosage and Administration:
• Initial: 500 mg orally twice a day or 850 mg once a day.
• Maximum: 2550 mg per day.
• Route: Oral
• Contraindications:
• Renal impairment, metabolic acidosis, diabetic ketoacidosis.
• Side Effects:
• Common: Nausea, vomiting, diarrhea.
• Serious: Lactic acidosis.
 Cont…
• Interactions:
• Alcohol (increased risk of lactic acidosis), contrast dye (risk of renal
impairment).
• Nursing Considerations:
• Monitor blood glucose levels regularly.
• Assess renal function before starting therapy and periodically thereafter.
• Educate patients to take the medication with meals to reduce gastrointestinal
side effects.
• Monitoring Parameters:
• Blood glucose levels, HbA1c, renal function tests (creatinine clearance).
Reference:
• Clinical Pharmacology
• Pharmacology For Nurses