Drug Classifications and Prototypes 

• Therapeutic classes group drugs based on their clinical use or therapeutic effect
  • Antihypertensives treat high blood pressure by lowering blood pressure through various mechanisms (ACE inhibitors, beta-blockers)
  • Antidepressants treat depression by altering neurotransmitter levels or activity in the brain (SSRIs, SNRIs, TCAs)
  • Analgesics relieve pain by acting on pain receptors or pathways in the body (opioids, NSAIDs, acetaminophen)
• Pharmacologic classes group drugs based on their mechanism of action or chemical structure
  • Beta-blockers block beta-adrenergic receptors in the heart and blood vessels, reducing heart rate and blood pressure (atenolol, metoprolol)
  • Selective serotonin reuptake inhibitors (SSRIs) inhibit serotonin reuptake in the brain, increasing serotonin levels and improving mood (fluoxetine, sertraline)
  • Opioids act on opioid receptors in the brain and spinal cord to produce analgesia and other effects (morphine, oxycodone, fentanyl)

Prototype approach for drug classes

• Prototype drugs serve as representative agents within a therapeutic or pharmacologic class
  • Exemplify key characteristics, mechanisms of action, and effects of the class
  • Allow for comparison and contrast of drugs within the same class
  • Help predict properties, side effects, and interactions of similar drugs
• Benefits of the prototype approach include:
  • Simplifies learning by focusing on essential features of a drug class (pharmacology, indications, adverse effects)
  • Facilitates understanding of relationships between drugs within a class (similarities, differences)
  • Enables educated guesses about unfamiliar drugs based on knowledge of the prototype
• Examples of prototype drugs:
  • Atenolol is a prototype for beta-blockers, demonstrating their mechanism of action and cardiovascular effects
  • Fluoxetine (Prozac) is a prototype for SSRIs, illustrating their antidepressant properties and side effect profile
  • Morphine serves as a prototype for opioids, showcasing their analgesic effects and potential for abuse and addiction

Federal regulations for controlled substances

• The Controlled Substances Act (CSA) regulates the manufacture, distribution, and possession of controlled substances
  • Categorizes drugs into five schedules based on medical use, abuse potential, and safety
    1. Schedule I: High abuse potential, no accepted medical use (heroin, LSD, marijuana)
    2. Schedule II: High abuse potential, accepted medical use with severe restrictions (morphine, oxycodone, amphetamines)
    3. Schedule III-V: Lower abuse potential, accepted medical use with varying restrictions (codeine, benzos, pregabalin)
• Prescribing practices for controlled substances:
  • Prescribers must register with the Drug Enforcement Administration (DEA) to prescribe controlled substances
  • Schedule II drugs require a written, signed prescription and cannot be refilled without a new prescription
  • Schedule III-V drugs may have oral or written prescriptions and can be refilled with limitations (up to 5 refills in 6 months)
• Impact on healthcare providers:
  • Increased responsibility to prevent abuse, misuse, and diversion of controlled substances
  • Thorough documentation and adherence to regulations required when prescribing controlled substances
  • Potential for legal consequences, license suspension, or revocation if regulations are violated
  • Need for ongoing education and vigilance to ensure safe and appropriate use of controlled substances in patient care

Pharmacokinetics and Pharmacodynamics

• Pharmacokinetics describes how the body processes a drug (absorption, distribution, metabolism, excretion)
  • Bioavailability refers to the fraction of an administered drug that reaches systemic circulation
  • Half-life is the time it takes for the concentration of a drug in the body to decrease by half
• Pharmacodynamics explains how drugs affect the body and produce their therapeutic effects
  • Therapeutic index compares the dose that produces a desired effect to the dose that causes toxicity
  • Adverse effects are unwanted or harmful reactions that occur as a result of drug administration
• Drug-drug interactions occur when one drug affects the activity of another drug when both are administered together