Basic Principles of Pharmacology

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					Basic Principles of

  Dr. Jarinyaporn Naowaboot
  School of Health Science,
  Mae Fah Luang University 2011
• Definition:
  Pharmacology is the scientific study of
  Pharmacology analyzes the breakdown
  and synthesis, biological activity,
  biological effects, and delivery of drugs.
        Sources of Drugs
• Any chemical substance taken into body
  for the purpose of affecting body
  function is referred to as a drug.

 1. Natural products: plants, animal and
 2. Synthetic products
      Sources of Drugs (cont.)
• Plants = primary source of substances used
  in human body
  • Berries, bark, leaves, resin from trees, roots
• Minerals = from the earth & soil
  • Iron, sulfur, potassium, silver & even gold
• Animals = substances from the glands,
  organs & tissues of animals
  • Pork insulin
• Synthetic = man made (test tube drugs)
              Sources of Drugs
• Plants
Example           Trade Name   Classification
Chinchona Bark    Quinidine    Antiarrhythmic

Purple Foxglove   Digitalis    Cardiotonic

Poppy Plant       Paregoric,   Antidiarrheal,
(Opium)           Morphine,    Analgesic,
                  Codeine      Analgesic,
             Sources of Drugs
• Minerals
Example        Trade Name         Classification
Magnesium      Milk of Magnesia   Antacid, Laxative

Zinc           Zinc Oxide Oint.   Sunscreen, Skin

Gold           Solganal, Auranofin Anti-inflammatory;
                                   Used in tx of
                Sources of Drugs
• Animals
Example            Trade Name           Classification
Pancreas of Cow,   Insulin; regular,    Antidiabetic
Hog                NPH, PZI             Hormone

Stomach of Cow,    Pepsin         Digestive
Hog                                       Hormone

Thyroid Gland      Thyroid, USP         Hormone
Of Animals
             Sources of Drugs
• Synthetic
Example          Trade Name        Classification
Meperidine       Demerol           Analgesic

Diphenoxylate    Lomotil           Antidiarrheal

Co-Trimoxazole   Bactrim, Septra   Anti-Infective
                                   Used in the
                                   treatment of
Pharmaceutical dosage forms
  Pharmaceutical dosage forms
1. Liquid forms
• Solutions
  • Water or oil-based
• Tinctures
  • Prepared using an alcohol extraction process
• Suspensions
  • Preparations in which the solid does not dissolve
    in the solvent
• Emulsions
  • Suspensions with an oily substance in the solvent
 Pharmaceutical dosage forms
Liquid forms (cont.)
• Spirits
  • Solution of a volatile drug in alcohol
• Elixirs
  • Alcohol and water solvent, often with
• Syrups
  • Sugar, water, and drug solutions
   Pharmaceutical dosage forms
2. Solid forms
   • Powder>>bulk powder, devided powder,
       dusting powder, douche powder, insufflation,
       effervescent salt
   • Granule>> effervescent granule
   • Capsule
   • Tablet>>sugar-coated tablet, film-coated tablet,
       enteric-coated tablet, sustained-release tablet,
       effervescent tablet, sublingual tablet,
       troche(lozenge), pellet, vaginal tablet, chewable
       tablet, implantation tablet
Pharmaceutical dosage forms

3. Semisolid forms
  •   Ointment
  •   Paste
  •   Cream
  •   Suppository
 Pharmaceutical dosage forms
4.   Others
•    Aerosol
•    Spray
•    Inhalant
       Drug standard & drug
• Drug standard
  •   United States Pharmacopoeia (USP)
  •   National Formularly (NF)
  •   British Pharmacopoeia (BP)
  •   British Pharmacopoeia Codex (BPC)
  •   Pharmacopoeia Internationalis (PHI)
• Drugs are categorized under broad
  subcategories called classifications
• Drugs with several types of therapeutic
  effects fit under several classifications
         Drug Classifications
• Therapeutic Effect
  •   Antihypertensive
  •   Antiemetic
  •   Antibiotic
  •   Diuretic
• Physiologic Action
  • B-adrenergic blocker
  • Ca channel blocker
      Classifications (cont.)
• The same drug may belong to more than
  one classification
  • Propranalol: B-blocker (physiologic action),
    antianginal, antiarrhythmic, antihypertensive
  • Perphenazine: antiemetic =controls N/V,
    antipsychotic = anticholinergic side effects
    (dry mouth, constipation, urinary retention,
    blurred vision, tachycardia, sedation)
Nomenclature/Classifications (cont.)

 • Prototype Drug = representative of
   many drugs within the class
   • Diazepam: Benzodiazepine,
     sedative/hypnotic, antianxiety
   • Similarities: pharmacokinetics,
     pharmacodynamics, effects, side effects,
     adverse reactions, contraindications,
     drug/food interaction
 Nomenclature / Drug Names
• Generic
  • Name given to drug before it becomes
  • Given by the United States Adopted Names
  • Typically derived from chemical name
  • Usually shorter
Nomenclature / Drug Names (cont.)

• Trade
  • Name that is registered by the
  • Followed by the trademark symbol®
  • Can only be used by the manufacturer
  • May have several trade names (depending
    on number of manufacturers)
  • The first letter of the name is capitalized
Nomenclature / Drug Names (cont.)

  • Chemical
     • Gives exact chemical composition of the
     • Places atoms or molecular structure

Nomenclature / Drug Names (cont.)

 • Official
   • Name listed in the United States
     Pharmacopoeia-National Formulary
   • May be the same as the generic name
 • Acetaminophen/N-acetyl-p-
   aminophenol/Tylenol, Datil
Nomenclature / Drug Names (cont.)
• When a new drug is produced it is given a
  generic name
• It must be tested and approved by the FDA
• Listed in the USP/NF by an official name
• Producing company has an exclusive right for
  17 years and other companies can produce
  the same drug, but will assign own trade
Nomenclature / Drug Names (cont.)
• Patient Education
  • Generic and trade name drugs have same basic
    ingredients by law
• Trade name drug is more expensive
  • Advertising
  • Pharmacy dispension
  • Though basic ingredients are same, the “fillers” may
    be different (fillers may effect speed drug is dissolved
    or takes effect, some dyes may cause allergic
Nomenclature / Drug Names (cont.)

• Combination drugs
  • Have several generic names, but only one
    trade name
  • Darvocet-N-100 = Acetaminophen 650mg,
    Propoxypene napsylate, 100mg
Nomenclature / Drug Names (cont.)

• Trade names with numbers
  • The number refers to the amount of one
    of the generic components
  • A differentiating factor
  • Number represents the amount of the
    controlled substance
Nomenclature / Drug Names (cont.)
Trade Name             Generic Name
Empirin                Aspirin 325mg
Empirin #1             Aspirin 325 mg
                       Codeine Phosphate 7.5mg
Empirin #2             Aspirin 325 mg
                       Codeine Phosphate 15mg
The larger the number, the greater the amount of
  the controlled substance contained therein.
Nomenclature / Drug Names (cont.)

 • Potential med errors
   • Trade name misinterpreted for the # of
     tablets to give
   • Allergic reaction to one of the generic
     components (check for aspirin allergy)
   • Giving 2 #3’s instead of one #4 (doubles
     the dose of aspirin from 325mg to 650mg)

• Action
  • Cellular changes that occur as a result of
    the drug
  • Know which body system is affected
  • Benadryl competes with histamine for cell
    receptor sites on effector cell
              Terms (cont.)
• Antagonism
  • The opposition between 2 or more
    medications ex. narcotics and naloxone
• Bolus
  • A single, often large dose of a drug. Often
    the initial dose
                  Terms (cont.)

• Contraindication
  • Condition for which the drug should not be given
  • Pregnancy, lactation
• Cumulative action
  • An increased effect caused by multiple doses of the same
    drug. Caused by buildup in the blood.
                   Terms (cont.)
• Hypersensitivity
  • A reaction to a drug that is more profound than
    expected and which often results in an exaggerated
    immune response
• Idiosyncrasy
  • A reaction to a drug that is significantly different from
    what is expected
• Indication
  • The medical condition for which the drug has proven
    therapeutic value
     • Benadryl = allergic skin reaction, mild Parkinsonian
       symptoms, nasal allergies
            Terms (cont.)

• Interaction
  • Other foods or drugs that may alter the
    effect of the drug
  • MAO inhibitors have major interaction,
    some causing BP changes and even death
                Terms (cont.)
• Pharmacodynamics
  • Study of the mechanisms by which drugs act to
    produce biochemical or physiological changes in the
• Pharmacokinetics
  • Study of how drugs enter the body, reach their site
    of action and are eliminated from the body
                 Terms (cont.)
• Potentiation
  • The enhancement of a drug’s effect by another drug
  • Eg. promethazine may enhance the effect of
    morphine; also alcohol and barbiturates
• Refractory
  • The failure of a patient to respond as expected to a
    certain medication
• Synergism
  • The combined action of 2 or more drugs that is
    greater than the sum of the 2 drugs acting
            Terms (cont.)

• Side Effects & Adverse Reaction
  • List of possible unpleasant or dangerous
    secondary effects other than the desired
  • Benadryl causes sedation, dizziness,
    thickening of bronchial secretion
  • Ototoxicity – aspirin
  • Nephrotoxicity – gentamycin
  • Photosensitivity – antipsychotic/Haloperidol
                Terms (cont.)
• Therapeutic Action
  • The intended action of a drug given in an appropriate
    medical setting
• Therapeutic Threshold
  • The minimum amount of a drug that is required to
    cause the desired response
• Therapeutic Index
  • The difference between the therapeutic threshold
    and the amount of the drug considered to be toxic
  • Often referred to as Safe and Effective range
              Terms (cont.)
• Tolerance
  • The decreased sensitivity or response to a
    drug that occurs after repeated doses
  • Increased doses are required to achieve the
    desired effect
             Terms (cont.)

• Warning & Precaution
  • Conditions or types of patients that
    warrant closer observation for specific side
    effects when given drug
  • Hx of bronchial asthma, HTN
Six Rights of Drug Administration
•   Right   patient
•   Right   drug
•   Right   dose
•   Right   route
•   Right   time
•   Right   documentation
General Principles & Practices
3 label checks of med administration
• Check the label when taking the
  medication from its storage area
• Check the label before removing the
  med from its container
• Check the med before discarding or
  replacing the med container & before
  giving the medication to patient
          The Right Drug
• Interpret the drug correctly, check 3
• Clarify the order if necessary
• Never give meds prepared by others
• Never prepare or use med that is not
• Never leave meds at bedside
          The Right Dose
• Calculations must be correct
• Appropriateness of the dose must be
  checked (# of tabs, decimals, etc)
           The Right Time
• Place drug on the right time schedule
• Give meds at least within 30 minutes of the
  scheduled time
• Antibiotics should be given on time (know q
  8h vs tid)
• PRN meds should be given at times specified
• Check MAR for dates & time to see when the
  drug is to be discontinued
          The Right Route
• Depends on drug properties & pt
  physical/mental condition
• Route affects degree of absorption
• If in doubt, verify the order with MD
        The Right Patient
• Check name band & ask pt to state
  his/her name
• Never give med to pt who does not
  have name band
• Check for allergies
       Right Documentation
• MAR (most require you to write in data)
• Document only after giving drug
• If administration time differs from prescribed
  time, note time differences and explain why
• If you don’t give a med, initial the appropriate
  space, circle your initials, and follow agency’s
  policy to document why it wasn’t given
• Use only black ink
       Documentation (cont.)
• Medication Errors
  •   Immediately assess patient
  •   Monitor continuously if indicated
  •   Tell nurse-manager (instructor)
  •   Notify health care provider
  •   Complete medication error report
  •   Follow agency’s policy
         Patient Statements
• Pt complaints may indicate adverse reaction
  (ringing in ears, N/V, dizziness) notify MD
  before administering drug
• Comments that the med looks different or
  that the MD discontinued the med must be
• Change in condition, vital signs, or
  appearance of new symptoms may indicate
  that the drug should be withheld or MD
   Methods of administration
1. Enteral route
• GI route
• Intended for absorption in the stomach
  and intestine
• Most frequent &
  convenient/comfortable & generally the
  safest & usually the cheapest
• Slower onset, prolonged but less potent
        Enteral Route (cont.)
• Do not give if
  •   Impaired swallowing
  •   NPO
  •   Unconscious
  •   Nausea/vomiting
       Enteral Route (cont.)
• 2 Forms
  • Solids: tablets, capsules, pills
     • Enteric coated for absorption in small intestines
     • Do not crush or chew (use paper cup)
  • Liquids: elixirs, suspensions, syrups (some
    water based, some alcohol based)
        General Principles
• Give most important meds first
• Never dilute liquid meds unless specifically
• Always stay with the patient while taking meds
  (to be sure that they took it and that they do
  not choke on the meds)
• Do not leave meds at the bedside unless
  specifically told to do so
  • NTG
  • Eye drops
  • Antacids
            Parenteral route
1.   Intravenous route (iv)
2.   Intraarterial route (ia)
3.   Intramuscular route (im)
4.   Subcutaneous route (sc)
5.   Intrasubcutaneous route (isc)
6.   Intraperitoneal route (ip)
7.   Others
        Percutaneous Routes
• Medications are absorbed through the skin &
  mucous membrane. Most percutaneous meds
  produce local action, but some produce
  systematic action.
• Absorption is rapid, but of short duration
• Topical meds are:
  •   Ointments
  •   Creams
  •   Powders
  •   Lotions
  •   Transdermal patch
     Sublingual Administration
• Drugs given SL bypass the liver, which reduces time
  required for necessary effect
• Meds placed under the tongue
• Do not swallow the meds
• Do not drink or eat until completely absorbed
• Quick route
• Buccal meds placed between the cheek and teeth or cheek
  and gum
• NTG usually ordered to be left at bedside for PRN use. Pt
  may take it to diagnostic departments when leaving the
  floor. Pt should notify the nurse of any usage of NTG and
  its effects.
       Eyedrops & Ointments
• Meds must be marked for “ophthalmic use”
• Meds are used for one pt only & not shared
• OS = left eye; OD = right eye; OU = both eyes
• Pull down on lower lid while pt looks upward to
  expose conjunctival sac
• Place med in conjunctival sac, not directly on
• With cotton, apply gentle pressure at inner corner
  of eye lid (inner canthus) for 1-2 min to prevent
  systemic absorption
• Adults & children > 3 years old, turn head & affected
  side up
• Pull ear lobe upward and back to straighten ear
• Give drops without touching ear with the dropper
• For children <3 years old pull earlobe downward &
• Tell pt to remain in the same position for several
  minutes to allow meds to drain be gravity
• Hyperextend pt’s neck
• Hold dropper above the nostril being
• Tell pt to hold that position for a few
  minutes to allow med to remain in place
• Place children’s head backward &
Drugs absorbed through the mucous
  membranes of the respiratory tract,
  producing a relatively limited effect, or
  systemic effect
• Hand held nebulizer (HHN)
• Metered dose inhaler delivers a measured
  dose of a drug with each push of a canister
• Pt should gently blow nose to clear nasal
             Drug Storage
• Drug potency can be effected by
  •   Temperature
  •   Light
  •   Moisture
  •   Shelf life
• Security of controlled medications
  • Double lock & key
Components of a Drug Profile
• Name
  • Generic, Chemical, & Trade Names
• Classification
  • Broad group to which the drug belongs
• Mechanism of Action
  • The way in which a drug causes it’s effects
• Indications
  • Why a drug is appropriate
Components of a Drug Profile
• Pharmacokinetics
  • How a drug enters & leaves the body
• Side Effects
  • Untoward or undesired effects
• Routes of Administration
  • How can the drug be given
• Contraindications
  • Why a drug cannot be given
Components of a Drug Profile
• Dosage
  • Amount of drug that should be given
• Contraindications
  • Why a drug should not be given
• Special Considerations
  • Pediatric patients
  • Geriatric patients
  • Pregnant patients
        Common Prescribing Errors
 Wrong drug (e.g. drugs that sound alike)
 Wrong dose
 Inappropriate Units
 Poor/illegible prescriptions
 Failure to take account of drug interactions
 Omission
 Wrong route/multiple routes (IV/SC?PO)
 Calculation errors (important in Paediatrics)
 Poor cross referencing
 Infusions with not enough details of diluent, rate etc.
  Poor cross-referencing between charts
 Once weekly drugs
 Multiple dose changes
Prescription abbreviations: common latin Rx terms

    ac (ante cibum)         before meals
    pc (post cibum)         after meals
    bid (bis in die)        twice a day
    po (per os)             by mouth, orally
    hs (hora somni)         at bed time
    prn (pro re nata)       as needed
    q 3 h (quaque 3 hora)   every 3 hours
    tid (ter in die)        3 times a day
    qid (quarter in die)    4 times a day
    qd (quaque die)         once a day
Thank you for your attention

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