Pharmacology

• Pharmacology


  The study of drugs and their interactions with living cells and systems
• Drugs are chemical substances used for diagnosis, treatment of disease, and prevention of disease
• Disciplines related to pharmacology

  • Pharmacotherapy
  • Pharmacodynamics
  • Pharmacokinetics
  • Pharmacy
  • Toxicology
• History of pharmacology


  • The first pharmacologist was the village medicine man who noticed by ingesting certain plants altered body functions or awareness
  • Useful agents are prescribed and dispensed through medicine, dentistry, pharmacy, and nursing
  • Physicians, veterinarians, dentists, optometrists, physicians' assistants, nurse practitioners, pharmacists, and dental hygienists
• Role of dental hygienist in pharmacology

  • Knowledge of a patient's medication/health history
  • Understanding of actions, indications, adverse reactions and therapeutic uses
• DH role in treating a client

  1. Obtain a detailed medication/health history

  2. Administer drugs in the office

  3. Handle emergency situations

  4. Schedule appointments

  5. Handle non-prescription medication and nutritional/herbal supplements
• Sources of information for dental hygienists

  • CDHO Knowledge Network
  • Printed material
  • Computer/online resources
  • Online journals
  • Develop a relationship with a pharmacist
• Drug names


  • Each drug has a chemical name, generic name, and trade/brand name
  • Generic substitution provides equivalent therapeutic results at a reduced cost
• If a client states having an allergy to lidocaine, octocaine cannot be used instead as they may not be biologically or therapeutically equivalent
• Canadian regulatory agencies


  • Health Canada
  • Food and Drug Act
  • Proprietary or Patient Medicine Act
  • Narcotic Control Act
• Clinical evaluation of a new drug

  1. Pre-clinical testing (animal studies)

  2. Phase 1 clinical trials

  3. Phase 2 clinical trials

  4. Phase 3 clinical trials

  5. New drug application
• Acts that regulate narcotics in Canada

  • Canadian Food and Drugs Act (FDA)
  • Controlled Substances and Drugs Act (CDSA)
• Canadian Food and Drugs Act (FDA)


  • Requires that drugs comply with prescribed standards
  • Prohibits sale of drugs that are contaminated or unsafe
• Controlled Drugs and Substance Act (CDSA)


  • Governs the possession, sale, manufacture, production, and distribution of narcotics
  • Requires that only authorized persons possess narcotic substances
• Clinical evaluation of a new drug

  1. Pre-clinical testing: Animal studies

  2. Phase 1: Small and then increasing doses given to limited healthy human volunteers

  3. Phase 2: Larger group of humans are given the drug

  4. Phase 3: Group of patients with the condition the drug is for

  5. Phase 4: Post marketing surveillance
• Clinical evaluation of a new drug takes 12 years from when drug is synthesized to pharmacy shelves with a cost of over 350 million dollars
• Pre-clinical testing: Animal studies

  • To measure acute/chronic toxicity
  • Determine median lethal dose
  • Teratogenic effects
  • Pharmacokinetic properties
• Pre-clinical testing lasts about 3 years
• Phase 1 clinical trials

  • To determine SAFETY! The biological effects, metabolism, safe dose range, and toxic effects
• Phase 2 clinical trials

  • To determine EFFECTIVENESS, if any adverse reactions then reported to FDA
• Phase 3 clinical trials

  • Both SAFETY, EFFICACY and DOSAGE are determined
• Phase 4 clinical trials

  • Post marketing surveillance. Toxicity of drug reported after released. Removed off shelves if toxic
• Efalizumab (Raptiva) was removed from the market due to toxicity
• The Controlled Drug and Substances Act (CDSA) sets current requirements for writing prescriptions
• Scheduled/category drugs


  • Schedule I
  • Schedule II
  • Schedule III
  • Schedule IV
  • Schedule V
• Requirements for prescribing controlled drugs

  • Requires a DEA (Drug Enforcement Agency) number
  • Schedule II and IV require a prescription
  • Schedule II prescription must be written in pen, DH may write the prescription but the prescriber must personally sign and is responsible for what is written
  • Schedule II cannot be telephoned in unless an emergency supply to be followed by a written prescription within 72 hours
  • Schedule II no refills
  • Schedule III and IV can be telephoned in and may be refilled no more than 5 times in 6 months
• The only Schedule 1 drug dental hygienists are allowed to prescribe is 0.12% chlorohexidine gluconate
• Package inserts (PI)


  • Literature about the drug between manufacturer and FDA
  • Provides information of chemical makeup of the drug
  • FDA-approved for use, contraindications, warnings, adverse reactions, drug interactions, dose and administration, and how it is supplied
• Black box warning


  • FDA requires manufacture to display in PI
  • Draws attention to WARNINGS for both prescriber and patient
  • For serious safety concerns
• Labeled and off-label uses

  • FDA uses of drugs for specific indications, listed on PI
  • Any usage outside the labeled indications is called "off-label". Pharmacist cannot discuss or provide literature to prescribers for off-label uses
• Orphan drugs


  Developed to treat rare medical conditions
• Drug recall


  • Recall from use by manufacturer at the request of the FDA, or FDA under statutory authority
  • Recalled if there is reasonable probability that their use will have serious adverse health effect and/or death
• Prescription


  An ORDER for a specific medication for a specific patient at a particular time, with appropriate instructions for how the patient is to use the prescribed medication
• Metric system of measurement

  • Solid= weight=milligrams (mg)
  • Liquid=volume= milliliters (mL) or liter (L)
  • Sometimes grams (gm) or micrograms (ug)
• Household conversions


  • 1tsp (teaspoon) = 5mL
  • 1 tbsp (tablespoon) = 15mL
• Prescription format


  • Heading: Name, address, telephone number of prescriber (printed), Name, address, age and telephone number of the patient (written), Date of prescription
  • Body: "Rx" Symbol, Name and Dose Size/Concentration of drug, Amount to be dispensed, Directions to patient
  • Closing: Prescriber's Signature, DEA number, Refill Instructions
• The age of the patient is noted on the prescription to provide appropriate dosing
• The date is included on the prescription to ensure it is current and valid
• Prescription abbreviations


  • q: every
  • d: day
  • h: hour
  • qd: every day
  • qod: every other day
  • hs: at bedtime
  • ac: before meals
  • pc: after meals
  • prn: as needed
  • stat: immediately
  • bid: twice per day
  • tid: three times per day
  • qid: four times per day
  • ud: as directed
  • PO: by mouth
• Prescription label regulations


  • Law requires ALL PRESCRIPTIONS be labeled with NAME of MEDICATION and STRENGTH
  • Allows for easy identification especially in an emergency