Properties of Medicine

• OBJECTIVES


  • Differentiate the properties of medicine
  • Classify medicine based on their characteristics
  • Enumerate the advantages and disadvantages of medicine
• Appendicitis


  Inflammation of the appendix
• Constipation


  Not a digestive disorder
• Dyspepsia


  Symptoms do not include black tarry stools
• Peptic ulcers


  May be caused by all except malignant tumors in the stomach or pancreas
• Drug


  Any chemical that brings about a change in biologic function through its chemical actions
• Agonist


  A substance that acts as an activator, or promotes activity of a specific regulatory system or body process
• Antagonist


  A substance that acts as an inhibitor, having the opposite effect to the agonist
• Receptor


  A regulator molecule that receives the agonist or antagonist molecule and sends the signal to the body system it regulates
• Characteristics for a drug to be an effective pharmacological drug

  • The drug must have a very specific size, shape, atomic configuration and electrical charge to be able to interact with the receptor
  • A drug must have the necessary properties to travel to its site of action or receptor from its site of administration
  • It must be easily inactivated or excreted from the body once it has been used for its purpose
• Hormones


  Drugs that are synthesized within the body
• Poisons


  Drugs with harmful effects, any drug or hormone in extremely high amount can have harmful effects
• Toxicants


  Substances that produce adverse biological effects, may be chemical or physical in nature, effects may be of various types (acute, chronic, etc)
• Toxins


  Specific proteins produced by living organisms, most exhibit immediate effects
• Poisons


  Toxicants that cause immediate death or illness when experienced in very small amounts
• Physical and chemical nature of drugs

  • Solid (e.g. aspirin)
  • Liquid (e.g. ethanol)
  • Gas (e.g. nitrous oxide)
• Drug size


  The drug size must high enough to be unique to a receptor (this determines the lower limit of drug size, 100 Molecular Weight (MW) – a drug ideally should not be lower than this)
• Covalent bond


  Very strong bonds that are not readily broken, e.g. aspirin forms a covalent bond with its target enzyme, cyclooxygenase
• Electrostatic bond


  Much more common type of bond in drug-receptor interactions, can be relatively strong ionic linkages or weaker hydrogen bonds or very weak induced dipole interactions such as Van Der Waals forces
• Hydrophobic bond


  Quite weak, usually found in the interactions between highly lipid-soluble drugs and lipids in the cell membranes
• Prescription-only medicine (POM)


  Must be prescribed by a doctor or other authorized health professional and dispensed from a pharmacy or specifically licensed place, e.g. antibiotics and medicines for high blood pressure
• Pharmacy (P) medicine


  Can be bought only from pharmacies and under a pharmacist's supervision, e.g. emergency contraception and medicines containing codeine
• Over-the-counter (OTC) medicine


  General sale medicines for common, easily recognized ailments which usually last around 2-3 days and cause few troublesome side effects in normal use, e.g. small packs of painkillers and antihistamines
• Therapeutic classification


  Describes the clinical purpose, of the physiological change induced by the drug, e.g. antipsychotics, antidepressants, anticonvulsants, antinauseants
• Pharmacological classification


  Describes the specific thing that the drug does on the molecular level to elicit the desired physiological effect, e.g. calcium channel blockers
• Therapeutic and pharmacological classification examples

  • Bisacodyl
  • Diazepam
  • Losartan
  • Ondansetron
  • Celecoxib
  • Rosuvastatin
  • Ibuprofen
  • Rituximab
  • Aspirin
  • Benazepril
  • Naproxen
  • Captopril
  • Diclofenac
  • Enalapril
• Medicines to classify


  • Diclofenac
  • Losartan
  • Aspirin
  • Captopril
  • Diazepam
  • Loperamide
  • Ibuprofen
  • Bisacodyl
  • Rosuvastatin
  • Benazepril