Pharmacology

• What is the definition of pharmacology?

  The study of drug effects on living systems
• How is a drug defined?

  A substance recognized by a pharmacopoeia
• What must drug molecules do to produce a pharmacological response?

  Exert chemical influence on cell constituents
• What are drug targets?

  Binding sites on cells and tissues
• What are most drug targets composed of?

  Protein molecules
• What is pharmacodynamics?

  Describes the molecular action of a drug
• What happens when a drug is administered?

  It reaches discrete sites called receptors
• What are the general principles of pharmacodynamics?

  • Drugs act on target proteins
  • Target proteins include receptors, enzymes, carriers, and ion channels
• How do agonists function in pharmacodynamics?

  They fit well at receptor sites and elicit action
• What do antagonists do in pharmacodynamics?

  They block other drugs from attaching to receptors
• What is the role of enzymes in pharmacodynamics?

  Drugs alter enzymes necessary for body functions
• What are ion channels in pharmacodynamics?

  Gateways that allow selective ion passage
• What does pharmacokinetics study?

  The time course of drug absorption and excretion
• What is drug absorption?

  The passage of a drug into the plasma
• What are the routes of drug administration?

  • Oral
  • Sublingual/Buccal
  • Rectal
  • Epithelial surfaces
  • Inhalation
  • Injection
• What factors affect gastrointestinal absorption of drugs?

  Gut content, motility, blood flow, particle size
• Why is sublingual administration used?

  For rapid response or unstable drugs
• What is the fastest route of drug administration?

  Injection administration
• What is drug metabolism?

  Breakdown of substances by enzymatic conversion
• What is drug excretion?

  Irreversible loss of drug from the body
• How does drug distribution occur?

  Movement from circulation to tissue or site of action
• What are the divisions of the nervous system?

  • Central nervous system (CNS)
  • Peripheral nervous system (PNS)
  • Motor
  • Sensory
  • Autonomic nervous system
  • Sympathetic division
  • Parasympathetic division
• What does the autonomic nervous system control?

  Body systems functioning without conscious thought
• What is a synapse?

  A break in the continuity of a nerve
• How do topical ophthalmic drugs interact with the ANS?

  They can mimic or block neurotransmitter effects
• What are cholinergic fibers?

  Fibers that release acetylcholine (ACh)
• What are adrenergic fibers?

  Fibers that release norepinephrine (NA)
• What is the origin of parasympathetic innervation of the eye?

  Edinger Westphal nucleus in the midbrain
• What is the pathway for sympathetic innervation of the eye?

  Originates in the hypothalamus and travels down
• What determines the response of a cell to a neurotransmitter?

  The receptor type, not the neurotransmitter
• What are the predominant receptors of the iris sphincter?

  Muscarinic receptors responding to ACh
• What do agonists do in pharmacology?

  Replicate the action of a neurotransmitter
• What is a direct-acting agonist?

  Acts on receptor sites of the effector
• What is an indirect-acting agonist?

  Excites a nerve fiber to release neurotransmitter
• What do antagonists do in pharmacology?

  Block receptor sites or neurotransmitter release
• What are the types of drugs relevant to optometrists?

  • Parasympathomimetics
  • Antimuscarinics
  • Sympathomimetics
• What do parasympathomimetics do?

  Stimulate the parasympathetic system
• What is the effect of antimuscarinics?

  Produces mydriasis and cycloplegia
• What do sympathomimetics do?

  Stimulate the sympathetic system