Introduction to Pharmacology

Introduction to Pharmacology

• Pharmacology involves studying drugs and their impact on life processes.
• It's a key science in modern medicine, aiding in disease treatment and saving lives.
• The term comes from the Greek word "pharmakon," initially meaning a magic charm, later evolving to mean remedy or drug.

Historical Context

• Around 2100 BCE, early effective drugs were simple external treatments like cool mud.
• Ancient prescriptions from this time included thyme-containing salves.
• By 1500 BCE, Egyptians used castor oil and opium in their prescriptions.
• Ancient Chinese scrolls listed herbal medicine prescriptions for over 50 diseases.
• Modern goal includes understanding how drugs interact with biological systems for rational use in diagnosis and treatment.

Application of Pharmacology in Nursing

• Nurses administering medications follow the Five Rights of Drug Administration: right drug, patient, dose, route, and time.
• A Sixth Right has been added recently: right documentation.

Application of Pharmacology in Patient Care

• Seven aspects of drug therapy include:
  • Preadministration assessment
  • Dosage and administration
  • Evaluating and promoting therapeutic effects
  • Minimizing adverse effects
  • Minimizing adverse interactions
  • Making PRN decisions
  • Managing toxicity

Pharmacology in Patient Education

• Patient education on drugs includes:
  • Drug name and therapeutic category (e.g., penicillin: antibiotic)
  • Dosage size
  • Dosing schedule
  • Route and technique of administration
  • Expected therapeutic response and its timeline
  • Non-drug measures to enhance therapeutic responses
  • Duration of treatment
  • Method of drug storage
  • Symptoms of major adverse effects and ways to minimize discomfort
  • Major adverse drug-drug and drug-food interactions
  • Whom to contact for therapeutic failure or severe adverse reactions

Complementary and Alternative Medicine

• Complementary and alternative medicine (CAM) includes diagnostics, treatments and/or prevention which complements mainstream medicine.
• CAM contributes to overall healthcare, fulfills unmet demands, or diversifies medicine's conceptual frameworks.
• It encompasses a large array of techniques with therapeutic and diagnostic approaches.
• CAM refers to medical products and care practices that aren't part of the standard options.
• Integrative medicine combines conventional medicine with evidence-based CAM practices.
• It considers patient preferences and addresses mental, physical, and spiritual aspects of health.
• Conventional medicine, or allopathic medicine, treats symptoms and diseases with drugs, radiation, or surgery.

Complementary vs. Alternative Medicine

• With complementary medicine, non-standard treatments are used along with standard medical care.
• Alternative medicine involves using non-standard treatments instead of standard medical care.

Types of Complementary and Alternative Medicine

• Mind-body therapies focus on the interaction between the mind and body.
• Biologically based practices use substances found in nature like herbs and foods.
• Manipulative and body-based practices involve movement or manipulation of the body.
• Energy healing involves channeling energy to promote healing.
• Whole medical systems are complete systems of theory and practice.

Legal and Ethical Aspects of Drug Therapy

• Safe medication administration is a crucial nursing task focused on patient safety.

Drug Development and Safety

• The drug development process is guided by phases:
• Phase I: new drug discovery.
• Phase II: testing on people with the specific disease.
• Phase III: safety and efficacy testing compared to existing treatments.

Controlled Substances

• Schedule I drugs have a high abuse potential with no accepted medical use, such as heroin and marijuana.
• Schedule II drugs have high abuse potential leading to severe dependence, like cocaine and morphine.
• Schedule III drugs have abuse potential less than Schedules I and II, with moderate dependence.
• Schedule IV drugs have moderate abuse potential leading to limited dependence, like alprazolam.
• Schedule V drugs have small abuse potential leading to limited dependence, like cough medications with codeine.

Drug-Induced Organ Toxicities

• Cardiotoxicity can lead to cardiomyopathy and be caused by doxorubicin.
• Damage to blood-forming organs can lead to agranulocytosis from clozapine.
• Liver damage may result in cholestatic jaundice or hepatitis from isoniazid.
• Kidney damage can lead to acute tubular necrosis from NSAIDs.
• Ototoxicity can result in vestibular and cochlear disorders from aminoglycosides.
• Lung damage can cause inflammatory fibrosis can result from bleomycin.
• Skin toxicity such as skin rashes is caused by phenytoin.

Pregnancy and Lactation

• Drug usage during pregnancy can impact the fetus.
• The greatest risk for developmental abnormalities (teratogenic effects) exists during the 4th to 10th week of pregnancy. During this time major organs are developing..
• After the 10th week the greatest risk is in the development of the brain and the spinal cord
• Drug safety categories during pregnancy range from Category A (no risk) to Category X (contraindicated). They are designated by letters, ranging from A being safe for use in pregnant women to X being not safe and known to cause harm to fetuses

Drug Classification by Chemical Class

• Drugs can be categorized by chemical structure.
  • Examples include B-lactam antibiotics, benzodiazepines and anti-androgen pharmaceuticals.
• Drugs may be grouped based on their biological target.
  • A few examples include 5-Alpha-reductase inhibitor, Angiotensin II receptor antagonist, ACE inhibitor and Alpha-adrenergic agonist
• Classifications based on the condition induced includes-
• Antifungals that stop growth of fungi
• Antimicrobials which kill microbes and bacteria
• Antithrombotics which prevent formation of clots etc

Basic Principles of Pharmacology- Prescriptions

The differences between OTC (over the counter) drugs and prescribed drugs includes:

• Over the counter drugs doesn't require prescriptions
• Can be bought from the shelf
• Can be regulated by FDA

Understanding Drug Actions

• Therapeutic drug classification depends on the pathology treated:.
  • Analgesics relieve pain.
• Antibiotics combat bacterial infections.
• Anticoagulants prevent blood clotting.

Rights of Drug Administration

• The 10 Rights of Drug Administration include: right patient, medication, dosage, route, time, documentation, client education, right to refuse, right assessment, and right evaluation.

Measurement Systems

• Metric system is a decimal system used in hospitals and clinics.
• Apothecary includes grains (gr), minims (m), drams (dr) and ounces (oz).

Routes of Drug Administration: Topical, Enteral, and Parenteral

• There are a number of methods for the administration of pharmaceutical drugs for treatment of disease like topical, enteral, and parenteral etc
• Topical includes applying medicine to the skin nose etc.
• Enteral: includes Buccal, Sublingual or swallowed medicines
• Parenteral: includes sub cutaneous Intramuscular and intravenous

Drug Movement and Modification

• When administering a drug with either oral or suppository administration for example it undergoes a " first pass effect" ie it goes through the GI tract before going into the blood stream
• Other administrations that bypass the first pass effect include IV injection and topical administrations

Absorption and Distribution

• Once medicines have been administered and absorbed, they can go through the blood stream and exert effects etc