M3-DISPENSING

• Prescription information

  • Prescriber's information
  • Patient's information
  • Date prescription was written
  • Superscription - Rx symbol
  • Inscription - medications
  • Subscription - instructions to RPh
  • Transcription (signa) - directions for patient
  • Special instruction
  • Prescriber's signature & license number
• Types of Drugs

  • Non-Rx or OTC drugs
  • Rx or ethical drugs or legend drugs
  • Special type: dangerous drugs
• List A

  • Prohibited
  • Regulated
• Requirements for dangerous drugs

  • S2 license - doctor
  • Dangerous drugs book
  • Special DDB Rx (Form 172)
• Triplicate prescriptions

  • Issued by DOH, made by DDB
  • Accomplished in triplicate
  • Yellow - original, pharmacist
  • Green - duplicate, patient
  • White - triplicate, MD
  • Partial filling is allowed
  • Refills are not allowed
• Prescription Errors

  • Erroneous
  • Violative
  • Impossible
• Erroneous prescription

  • The brand name precedes the generic name
  • The generic name is the one in parenthesis
  • The brand name is not in parenthesis
  • Fill; report to DOH
• Violative prescription

  • The generic name is not written
  • The generic name is not legible and a brand name that is legible is written
  • No substitution is indicated
  • Do not fill; report to DOH
• Impossible prescription

  • Only the generic name is written but is not legible
  • Generic name does not correspond to brand name
  • Both generic name and brand name are not legible
  • Drug is not registered with the FDA
  • Do not fill; report to DOH
• Dispensing Incompatibilities

  • Physicochemical
  • Therapeutic
• Physical Incompatibilities


  • Insolubility & immiscibility
  • Polymorphism
  • Liquefaction
  • Sorption
  • Dehydration (water loss)
  • Volatilization (vaporization)
• Chemical Incompatibilities


  • Redox
  • Hydrolysis
  • Acid-base reaction (neutralization)
  • Photochemical degradation
  • Optical isomerism
  • Cementation
  • Gelatinization
  • Explosive combination
  • Polymerization
• Therapeutic Incompatibilities

  • Drug-herb
  • Drug-lab
  • Drug-food
  • Drug-drug
• Pharmacodynamics

  • Addition: 1 + 1 = 2
  • Synergism: 1 + 1 = >2
  • Antagonism: 1+ 1 = 0
  • Potentiation: 1 + 0 = 2
  • Electrolyte concentration
• Pharmacokinetics


  • Absorption
  • Alteration of pH
  • Alteration of GI flora
  • Complexation/ Adsorption
  • Alteration of GI motility
  • Distribution
  • Plasma proteins
  • Metabolism
  • Enzyme induction
  • Enzyme inhibition
  • Excretion
  • Alteration of pH
  • Alteration of active transport
• Adverse Drug Event (ADE)


  Any untoward medical occurrence during treatment
• Adverse Drug Reaction (ADR)


  A response to a drug which is noxious, unintended, & occurs at doses normally used in man
• Side Effect (SE)


  Unintended effect occurring at a normal dose
• Pharmacovigilance (PVG)


  Science and activities relating to the detection, assessment, understanding, and prevention of AEs
• Risk factors for ADRs

  • Age
  • Concurrent Medicines
  • Duration of Therapy
  • Gender
  • Comorbidities
  • Narrow TI
  • Ethnicity & Genetics
• Types of ADRs

  • Augmented (Type A)
  • Bizarre (Type B)
  • Continuous (Type C)
  • Delayed (Type D)
  • End of Use (Type E)
  • Failure of Therapy/ Efficacy (Type F)
• Type A (Augmented) ADR


  • Expected, extension of pharmacological action
  • Common, predictable, dose-dependent
• Type A (Augmented) ADR examples

  • Opioids - constipation
  • OHAs - hypoglycemia
  • Loop diuretics - hypokalemia
  • K-sparing diuretics - hyperkalemia
  • SSRIs - serotonin syndrome
  • Vasodilators - hypotension
• Type B (Bizarre) ADR

  • Unrelated to drug's pharmacological action
  • Unpredictable, not dose-dependent
  • Depends on patient's susceptibility
• Idiosyncratic ADR


  Unknown mechanism
• Type B (Bizarre) ADR examples

  • Sulfonamides - SJS
  • Vancomycin - Vancomycin Flushing Syndrome
• Immunological ADRs

  • Type I (IgE-mediated Anaphylactic Reaction)
  • Type II (IgG & IgM-mediated Cytotoxic Reaction)
  • Type III (IgG-mediated Immune Complex Reaction)
  • Type IV (T Cell-mediated Delayed Reaction)
• Type I (IgE-mediated Anaphylactic Reaction) examples

  • Penicillin & cephalosporins (cross-reactivity)
  • Dextrans
  • X-ray contrast media
• Type II (IgG & IgM-mediated Cytotoxic Reaction) examples

  • Chloramphenicol - aplastic anemia
  • Methyldopa - hemolytic anemia
  • ASA - idiopathic thrombocytopenic purpura
• Type III (IgG-mediated Immune Complex Reaction) examples

  • Drug-induced SLE
  • Jarisch-Herxheimer Reaction
• Type IV (T Cell-mediated Delayed Reaction) examples

  • Contact dermatitis - poison ivy (urushiol)
  • Tissue or organ rejection
  • Mantoux test
• Type C (Continuous) ADR

  Chronic use in supraphysiological doses
• Type C (Continuous) ADR examples

  • Steroids - Cushing's syndrome
  • Ethambutol - optic neuritis
  • Doxorubicin - cardiotoxicity
  • Opioids - dependence, tolerance, addiction
• Tolerance


  Decreased responsiveness to drug
• Tachyphylaxis


  Develop rapid tolerance
• Type D (Delayed) ADR

  • Occurs long after exposure (days, weeks, years)
  • Delayed onset; dose-dependent
• Teratogenic drugs

  • Vitamin A derivative (isotretinoin)
  • Phenytoin - fetal hydantoin syndrome
  • Valproic acid/ carbamazepine - neural tube defects
  • ACE inhibitors - Potter's syndrome
  • Lithium - Ebstein's anomaly
  • Methimazole - aplasia cutis
  • Warfarin - fetal warfarin syndrome
  • Antineoplastics - usually embryocidal
  • Alcohol - fetal alcohol syndrome
  • Estrogen-containing drugs - genital abnormalities
  • Tetracyclines - impaired bone growth
• Type E (End of Use) ADR

  Result of termination or sudden discontinuation
• Type E (End of Use) ADR examples

  • Opioids - withdrawal syndrome
  • Clonidine - rebound hypertension
  • Steroids - adrenal insufficiency (Addison's disease)
  • Benzodiazepines - rebound insomnia
  • Alcohol - disulfiram-like reactions
• Type F (Failure of Use) ADR examples

  • AMR (antimicrobial resistance)
  • Improper use
  • Wrong dose, route of administration
  • Drug interaction
  • Incompatibility
  • Non-compliance
  • Manufacturing errors/ toxic excipients
  • Counterfeit
  • Expired