Lesson 1

• Pharmacology is derived from the Greek word "Pharmakon," meaning drug, and "logos," meaning study
• Pharmacology is a science that deals with the study of drugs and their interaction with living systems
• Importance of studying pharmacology includes understanding drugs and their effects on living things, knowing the right dosage of drugs, identifying and responding to drug interactions, reactions, and side effects, and knowing when to use drugs because some conditions do not need drug therapy
• Understanding pharmacology involves knowing the process of drug intake, absorption, distribution, metabolism, and elimination, identifying the properties of ideal drugs, and applying pharmacology in nursing with regards to the five rights in drug administration
• Drug is defined as a substance used in the diagnosis, prevention, or treatment of a disease or symptom
• Pharmacokinetics is the study of the absorption, distribution, metabolism, and excretion of drugs (What the body does to the drug)
• Pharmacodynamics is the study of the effect of drugs on the body and their mechanism of action (What the drug does to the body)
• Chemotherapy is the use of chemicals for the treatment of infections, including malignancies
• Pharmacy is the science of identification, compounding, and dispensing of drugs, including the collection, isolation, purification, synthesis, and standardization of medical substances
• Therapeutics is the use of drugs in the prevention and treatment of disease
• Toxicology deals with the adverse effects of drugs and the study of poisons (Toxicon means poison in Greek)
• Knowledge of drugs and their uses in diseases dates back to the history of mankind, with ancient civilizations discovering medicinal effects of extracts from plants, animals, and minerals
• Hippocrates, Theophrastus, Pedanius Dioscorides, Paracelsus, and Valerius Cordus are key figures in the historical developments of pharmacology
• Francois Magendie established the foundation of modern pharmacology, while Rudolf Buchheim created the first pharmacological institute
• Claude Bernard discovered the role of the pancreas in digestion and the glycogenic function of the liver and was considered as the "Father of Experimental Medicine", while Oswald Schmiedeberg introduced the concept of pharmacodynamics and pharmacokinetics of a drug and was considered as "Father of Pharmacology"
• Sources of drugs include natural sources like plant-based, animal-based, mineral-based, and microorganism-based, as well as synthetic sources like cellular culture-based and recombinant DNA technology
• Drugs may have several names assigned to them, including chemical names, generic names, and brand names
• Routes of drug administration include Enteral/Per Orem, Parenteral, Local/Topical, and Inhalation
• Advantages of the Enteral route include being the safest, most convenient, most economical, allowing self-administration, and being non-invasive
• Disadvantages of the Enteral route include slower onset of action, time-consuming absorption, gastric irritant/unpalatable taste, alteration of absorption due to physical characteristics of drugs, irregularities in absorption, destruction of drugs by gastric juices, limitations in unconscious and uncooperative patients, and intensive first-pass metabolism
• Enteric coated tablets are designed to disintegrate in the small intestines (duodenum/jejunum) to prevent gastric irritation, drug destruction in the gastric mucosa, have a higher drug concentration in the small intestine, and slow absorption to prolong the duration of action
• Advantages of enteric coated tablets:

  • Frequency of administration may be reduced
  • Therapeutic concentration may be maintained for a long time, especially when symptoms are to be treated
• Disadvantages of enteric coated tablets:

  • More expensive
  • Early release may cause toxicity
• Parenteral administration routes, other than the enteral route, are known as parenteral routes and have advantages like more rapid action, suitability for unconscious and uncooperative patients, and less or no possibility of GI irritation
• Parenteral administration disadvantages include the need for asepsis maintenance, potential painful injections, higher cost, less safety, inconvenience, and the risk of nerve and tissue injury
• Intramuscular injections involve injecting an aqueous solution of the drug into large skeletal muscles for rapid and uniform absorption, with the deltoid muscle absorbing faster than the gluteal muscle
• Intravenous (IV) administration involves injecting the drug into superficial veins for immediate availability in the circulation, with advantages like rapid action, 100% bioavailability, and the ability to give large volumes quickly
• Intravenous (IV) administration disadvantages include the inability to withdraw the drug once injected, the potential for thrombophlebitis, difficulty in self-medication, and the requirement for sterile solutions
• Routes of administration like intraperitoneal, intrathecal, intra-articular, and intra-arterial have specific uses and precautions for drug delivery
• Inhalation of volatile liquids and gases allows for instant drug absorption and excretion through the lungs, with advantages like rapid action but the risk of irritant gases enhancing pulmonary secretions
• Transdermal routes involve applying highly lipid-soluble drugs over the skin for slow and prolonged absorption, with advantages like prolonged duration of action, constant plasma levels, and good patient compliance
• Transmucosal routes involve drug absorption across mucous membranes, including sublingual, nasal, and rectal routes, each with specific administration methods and examples of drugs used
• Transmucosal drug absorption involves drugs being absorbed across mucous membranes, including sublingual, nasal, and rectal routes
• Sublingual administration involves placing a tablet or pellet containing the drug under the tongue, examples include nitroglycerine, nifedipine, and buprenorphine
• Advantages of transmucosal drug absorption include fast absorption within minutes and the ability to spit out the drug after the desired effect is obtained to avoid unwanted effects
• Disadvantages of transmucosal drug absorption include the possibility of buccal ulceration
• Nasal drug administration allows drugs to be administered through the nasal route, examples include oxytocin spray, oxymetazoline, and budesonide for allergic rhinitis
• Rectal drug absorption involves drugs being absorbed from the upper part of the rectum and carried by the superior hemorrhoidal vein to the portal circulation, examples include indomethacin, chlorpromazine, and diazepam
• Rectal drug absorption is useful in geriatric patients and others with vomiting tendency and inability to swallow, but irritation of the rectum and irregular absorption may occur
• Rectal enema administration involves the administration of a drug in liquid form into the rectum, it can be evacuant or retention enema