Pharmacology Overview and Branches

Overview of Pharmacology

• Pharmacology combines knowledge of "pharmacon" (medicine/drug) and "logos" (science/study) to explore interactions between living organisms and chemicals.
• The focus is on understanding the effects of drugs on normal and abnormal biochemical functions.

Historical Context

• Early treatments for diseases utilized unconventional methods involving plants, animal products, and minerals, with a strong emphasis on herbal remedies.
• The term "drug" is derived from the French "drogue," indicating a historical reliance on dry herbs for medicinal purposes.

Branches of Pharmacology

• Pharmacodynamics: Study of drug actions and effects in the body.
• Pharmacokinetics: Study of how drugs are absorbed, distributed, metabolized, and excreted.
• Therapeutic: Art and science of treating diseases.
• Chemotherapy: Treatment of diseases with chemicals targeting microorganisms and cancer cells.
  • Subdivided into antibiotics and antineoplastic agents.
• Toxicology: Focuses on drug adverse effects and poisoning mechanisms.
• Clinical Pharmacology: Involves the application of pharmacological principles in clinical settings.
• Pharmacy: Practice of preparing and dispensing drugs.
• Pharmacognosy: Study of medicinal drugs derived from plants and other natural sources.
• Pharmacoeconomics: Evaluates the cost-effectiveness of drug therapies.
• Pharmacogenetics: Examines how genetic factors influence drug responses.
• Pharmacogenomics: Studies the broader genetic impact on drug efficacy and safety.
• Comparative Pharmacology: Compares different drugs within the same or various categories.
• Posology: Concerned with dosing of medications.
• Animal Pharmacology: Studies the effects of drugs in animals.
• Pharmacoepidemiology: Examines the use and effects of drugs in populations.

Drug Safety and Therapeutic Goals

• The administration of drugs involves a careful assessment of benefits versus risks, emphasizing safety.
• Essential medicines can pose significant risks at high doses, highlighting the importance of dose control.

Research Methods in Pharmacology

• Studies conducted can be observational (cohort studies), comparative (case-control studies), or involve clinical trials (Phase trials).

Steady State and Drug Interaction

• Steady state is achieved when drug intake equals elimination, keeping drug concentration in a therapeutic range.
• G-PACMAN inhibitors can affect drug metabolism: Grapefruit, Protease Inhibitors, Azole Antifungals, Cimetidine, Macrolides (excluding Azithromycin), Amiodarone, and Non-DHP Calcium Channel Blockers.
• Combining drugs from the same class can increase the risk of adverse effects, e.g., NSAIDs with anticoagulants can elevate bleeding risk.

Pharmacodynamics

• Pharmacodynamics involves understanding how drugs affect the body through various receptor types:
  • Ligand-Gated Ion Channels: Simple receptors that respond quickly to ligand binding.
  • G-Protein Coupled Receptors: Known as the "Seven Transmembrane Receptor," involved in complex signaling.
  • Enzyme-Linked Receptors: Cell-surface receptors reacting to extracellular signals.
  • Intracellular Receptors: Located within the cell, binding ligands to influence gene expression.

Drug Classification

• Medications are classified based on mechanism of action, physiologic effect, and chemical structure to ensure safe, effective use.
• Drug classification aids in predicting side effects and choosing suitable alternatives when a drug fails.

Drug Resistance

• Incorrect or prolonged use of medications can lead to antibiotic resistance, diminishing treatment efficacy.
• Example: Chronic infections may become resistant to the primary drug and other similar medications.

Contrast Media

• Metformin must be withheld for 48 hours post-contrast administration to prevent contrast-induced renal failure.
• Osmolality affects tolerability; closer osmolality to blood is termed “iso-osmolar” and is generally safer.
• High-osmolar contrast media (HOCM) are associated with increased adverse reactions, whereas low-osmolar contrast agents (LOCM) are preferred in clinical practice.

The Six Rights of Drug Safety

• Right Patient: Verify patient identity to avoid administering incorrect medications.
• Right Medication: Check medication label against the order for accuracy in strength and type.
• Right Dose: Ensure the correct dosage is administered, recognizing variations in strength among formulations.
• Right Time: Adhere to scheduled doses to maintain effective therapeutic levels.
• Right Route: Understand that the method of administration can alter drug effectiveness.
• Right Documentation: Document all administration details accurately to prevent future errors.

Route of Administration

• Various administration routes impact drug action, including:
  • Oral
  • Intravenous (IV)
  • Subcutaneous (SubQ)
  • Intramuscular (IM)
  • Transdermal
  • Rectal
  • Inhalation
  • Sublingual

Ethical and Professional Responsibilities

• Healthcare professionals must adhere to ethical standards including informed consent, confidentiality, and delivering services within their qualifications.
• Ensure patient safety by advocating for minimal radiation exposure when necessary.

Intravenous Considerations

• When administering IV medications, assess for allergies, asthma, renal insufficiency, and anxiety to mitigate potential complications during treatment.

This quiz covers the fundamentals of pharmacology, including its historical context and various branches such as pharmacodynamics, pharmacokinetics, and chemotherapy. Explore the interactions between drugs and living organisms, and understand the evolution of medicinal practices throughout history.