Introduction to Basic Pharmacological Principles

1
Introduction to Basic Pharmacological Principles
2
What is a Drug???

• Any chemical substance that affects living
  systems by changing their structure or function

3
6--Subdivisions of Pharmacology

• 1Pharmacology
• History, sources, and physical and chemical
  properties of different drugs
• How drugs affect living systems
• 2Pharmacodynamics
• Biochemical and physiological effects of drugs
• Drugs mechanisms of action

4
6--Subdivisions of Pharmacology

• 3Pharmacokinetics
• Absorption, distribution, biotransformation
  (Metabolism), and excretion
• Effected by route used, concentration of the
  drug, time, etc.
• 4Pharmacotherapeutics
• How drugs are used in the treatment of illnesses

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6--Subdivisions of Pharmacology

• 5Pharmacognosy
• Drugs derived from herbal and other natural
  sources
• 6Toxicology
• Poisons and poisoningsToxic effects on living
  organisms

6
History of Drugs

• As old as history, Important for survival,
  Disease Great superstition
• Ancient Egypt is credited as being the cradle of
  pharmacologylisted over 700 different remedies
  to treat specific ailments
• Greece first systematic dissections of the
  human body to study the functions of organs.
• Paracelsus a Swiss scientist, advocated the use
  of single drugs. Father of Pharmacology.

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History of Drugs Cont

• 17th century demonstrated the circulation of the
  blood in the body and introduced a new way of
  administering drugsIV
• Lister and Semmelweis introduced antiseptics to
  prevent infection during surgery
• Ehrlichs discovery of antibiotics
• Banting and Best for insulin
• the Golden Age of Pharmacology

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4--Sources of Drugs

• 1--Natural Sources
• Examples Pancreas of animalsinsulin
• Nature claysKaopectate
• PlantsDigoxin, Metamucil
• 2Semi Synthetically
• Examples Prepared by chemically modifying
  substances that are available from natural source
• Animal insulin changed to be like human insulin

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4--Sources of Drugs

• 3Synthetic Means
• Examples Formed by chemical reactions in a lab.
  Synthroid. Greater purity than nature.
• 4Gene splicing involves the process of
  manipulating genes. The aim is to introduce new
  characteristics or attributes
• Examples can include the production of human
  insulin through the use of modified bacteria

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6 Major Uses for Drugs

• 1Symptomatic
• Relieve disease symptoms. Aspirin, Tylenol.
• 2Preventative
• To avoid getting a disease. Hepatitis B vaccine,
  Flu vaccine.
• 3Diagnostic
• Help determine disease presence. Radioactive
  dyes.

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6 Major Uses for Drugs

• 4Curative
• Eliminate the disease. Antibiotics.
• 5Health Maintenance
• Help keep the body functioning normally.
  Insulin.
• 6Contraceptive
• Preventative

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Dosage Forms

• 1Tablet Most popular and easiest to
  administer. Does not break the skin or mucous
  membranes
• --Scored tablets easiest to divide
• --Enteric-coated (EC) designed to carry drugs
  that irritate the stomach. Dissolve best in
  neutral or alkaline PH environment. AVOID
  administering antacids, milk, or other alkaline
  substances coating will dissolve. NEVER crush
  or chew.
• --Timed or Sustained Release Tablets permits
  drugs to be released from tablets in a controlled
  fashion. Eg Slow K crystals of potassium
  chloride embedded in a wax.
• IMPORTANT TO TAKE/GIVE THE METHOD ORDERED

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Dosage Forms Cont

• 2--Capsule, Pill Enclosed in either a hard or
  soft soluble shellusually gelatin. 10-20 minutes
  average time. NEED TO KNOW IF CAN OPEN
  CAPSULES TO MIX WITH LIQUIDS, FOOD Soft
  gelatin capsules--Usually encapsulate medicinal
  liquids
• 3--Troches, Lozenges Dissolve slowly in mouth.
  Usually exerts an antiseptic or anesthetic effect
  on the tissues of the oral cavity or throat.

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Dosage Forms Cont

• 4Suppository Can be inserted into one of the
  external body orifices (vaginal, rectal)
• 5Solution Clear liquid preparation. Easy
  administration. Often flavored.
• --Syrups sweetened solutions to mask the taste.
  
• --Elixir Solutions that contain alcohol and
  water. Used to dissolve drugs that do not
  dissolve in H20.
• --Tincture Solutions that contain alcohol as
  primary solvent. May be for external or internal
  use. Carefully check label

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More Dosage Forms

• 6Suspensions Liquid dosage forms that contain
  solid drug particles that are suspended in a
  suitable liquid medium. Mostly oral but may be
  lotions, liniments or injections. Never IV Shake
  thoroughly to mix
• 7Emulsion Dispersions of fine droplets of an
  oil in water or water in oil. SHAKE THOROUGHLY
  TO MIX
• 8Topical Patches applied to skin surface
  allows the drug to pass through the skin and into
  the bloodstream where they exert systemic
  effects. Examples Nitroglycerin, Nicotine, etc.

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Still More Routes

• 9Implants For extended periods of timeeg 5
  years for Norplant. Surgically implanted
  subdermally, often in upper arm region. Are
  small flexible capsules made of a Silastic
  polymer.
• 10--Parenteral Products either IV or injection
• --Ampules sterile, sealed glass or plastic
  containers usually containing only a single dose
• --Vials Either single-or multiple-dose glass or
  plastic containers that are sealed with rubber
  diaphragm
• --Prefilled syringes by prescription

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3 Different Names for Drugs

• 1 Chemical While under investigation, a drug
  is known this way usually in a code name of
  letters and numbers. Example??
• 2Trade/Brand or Proprietary Name
• Protected by patent given 17 years of exclusive
  rights Federal Trade-mark protected. Example??
• 3Generic Name assigned when drug went to
  market. Example??

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Drug Substitution

• 1Patent generics are the same drug just have
  different fillers and binders.
• 2--Chemical equivalent similar concentrations of
  the drug
• 3--Biological equivalent blood/tissue
  concentrations of the drug will be similar
• 3--Therapeutic equivalent drugs must be proven
  to be biologically equivalent before marketing
• Careful assessment is neededif any variations
  are made Some persons may have different
  reaction to generic or brand name if not been
  using that type

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Federal Regulatory Agencies

• FDA Determines which drugs will be marketed in
  the US. More stringent than comparable agencies
  in other countries. Thalidomide
• FTC Regulates trade practices of drug companies
  and prohibits false advertising.
• DEA Administers the controlled substance act of
  1970. Regulates the manufacture, distribution of
  drugs that have the potential for abuse
  narcotics, ANS stimulants and sedative-hypnotics.
• Omnibus Budget Reconciliation Act Requires RPh
  to counsel pts regarding drugs
• HIPAA Health Insurance Portability and
  Accountability Act (Privacy of pt information)

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Prescription Forms

• What are the 8 pieces of information that should
  be included on the prescription forms?
• 1. 5.
• 2. 6.
• 3. 7.
• 4. 8.
• Check answers next slide

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Prescription Forms

• 1Client information
• 2Date prescription was written
• 3The Rx symbol
• 4Name and dosage strength of the medication
• 5Dispensing instructions for the pharmacist
• 6Directions for the client or SIGNA
• 7Refill and/or specialized labeling instructions
  
• 8Prescribers signature, address, and telephone

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Legend Drugs

• Legend Drugs Labeled with Federal law
  prohibits dispensing without prescription.

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Storage of Medications

• Nurse needs to ensure the correct method for
  storage of medications. If not possible loss of
  potency stability
• Most are stable at room temperature but some may
  need refrigeration or be kept frozen
• Drug may become unstable or lose potency if it is
  not stored correctly
• Expiration Dates Pharmaceutical Co. cannot
  guarantee drug potency/stability/efficacy must
  be discarded
• Controlled Substances must be kept in double
  locked storage cabinets with accurate records of
  the disposition of all drugs received/used during
  each shift

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Controlled Substances Schedules

• Controlled Substance Act of 1970 Comprehensive
  drug abuse prevention and controlled substances
  act of 1970. This act also regulates the
  manufacture and distribution of drugs that may
  cause dependence
• Schedule I High potential for abuse and no
  accepted medical use in the US. EG LSD, heroin
• Schedule II High potential for abusebut have a
  currently accepted medical use in the US. Abuse
  could lead to severe psychological or physical
  dependence. EG meperidine, morphine, cocaine

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Controlled Substances Schedules Cont

• Schedule III Have accepted medical uses in the
  US. Lower potential for abuse than drugs in 1
  or2. EG Tylenol with Codeine, hydrocodone.
• Schedule IV Low potential for abuse than even
  Sch. 3 drugs. Abuse may lead to limited physical
  or psychological dependence. EG Librium, Valium
• Schedule V Lowest abuse potential of the
  controlled substances. Limited quantities of
  certain narcotic drugs. EG Lomotil, Robitussin
  A-C.

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Over the Counter (OTC) Drugs

• Prescription is not needed.
• Safe if used as directed, but could be toxic if
  not following label or physician directions
• Use caution with different combinations of OTC
  drugs or with certain medical conditions
• Many contain Tylenol, decongestants, or
  antihistamines. May mask symptoms. May antagonize
  symptoms of certain medical conditions (eg. High
  BP, heart problems, diabetes, etc)

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FDA Medical Products Reporting Program

• Intranet site look up for greater understanding
• http//www.fda.gov/medwatch/
• Purpose MedWatch allows healthcare professionals
  and consumers to report serious problems that
  they suspect are associated with the drugs and
  medical devices they prescribe, dispense, or use.
  Reporting can be done on line, by phone, or by
  submitting the MedWatch 3500 form by mail or fax.

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Principles of Drug Action

• Most common way that drugs work on bodyform a
  chemical bond with specific receptors within the
  body (Like a lock and key)
• Better the fit the stronger the drugs affinity
  and lower the dose needed.
• Agonist Drug which interact with a receptor to
  produce a response.
• Antagonist Inhibits or prevent the action of an
  agonist.
• Agonist-Antagonist Exert some of both responses.
  EG Morphine and Talwindepressant action
  reduced but some of the narcotic action will be
  evident.

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Drug Action Characterization

• Drug Any chemical substance used for the
  diagnosis, prevention or treatment of disease or
  to prevent pregnancy.
• Action
• Biochemical chemical processes and
  transformations in living organisms (blood sugar
  lowering drugs)
• Physiologic Something that helps normalize the
  body or body systems (anti-hypertensives)
• Organ system Involved in controlling or
  altering an organ system (CNS stimulants)

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Terms to Know

• 1Potency Strength of the medicine. Power.
• 2--Ceiling dose Maximum intensity of effect or
  response that can be obtained with a drug---No
  increased medicinal effects but MORE side
  effects.
• 3Route of Administration
• Passage across bodily membranes affects
  Absorption Distribution Mechanism of action
  Metabolism Excretion

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Terms to Know (Cont)

• 4--Side Effects Result because of a lack of
  specificity of action by the drug -- Acts not
  only on the tissues with which intended but also
  on other tissues (eg. antihistamines causing
  drowsiness/dizziness)
• 5Drug Toxicity predictable adverse drug
  effectUsually dose related
• 6Adverse Drug EffectsAnaphylaxis Less
  frequent than predictable side effects but more
  serious
• 7Teratogenic drug that will cause a congenital
  defect in an infant whose mother took the drug
  while pregnant.

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Terms to Know (Contd 2)

• 8Drug Tolerance Client develops a resistance to
  the effects of a drug. Characterized by the need
  for an increased dose or frequency.
• 9Physical Drug Dependence Body becomes
  accustomed to a drug and body cannot function
  normally unless drug is present.
• 10Psychological Drug Dependence Drug is the
  center of a persons thoughts, emotions, and
  activities.

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What is Pharmacokinetics???

• Study of the The absorption, distribution,
  biotransformation (Metabolism), and excretion of
  drugs
• 1Liberation
• Rate at which the solid drug is dissolved in
  gastric or intestinal fluids before it can be
  absorbed into the bloodstream. Fluids will
  increase rate. Each tablet or capsule varies.

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What is Pharmacokinetics???

• 2Absorption
• Process by which a drug passes from its site of
  administration into the fluids of the body that
  will carry it to its site(s) of action.
• A-- Presence of food, B--Acidity of the stomach,
  C--Amount of circulation
• 3Distribution
• Drug is carried from its site of absorption to
  its site of action.

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What is Pharmacokinetics???

• 4--Biotransformation (Metabolism) Converts drugs
  to more water-soluble form.
• Also permits the body to inactivate a potent drug
  before it accumulates and produces toxic effects.
  
• Location for Most Liver Liver enzymes.
• End product is than metabolites.

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What is Pharmacokinetics???

• Who would have impaired Liver function???
• A-Prematue infants/Neonates, B-Aged, C- Liver
  damage (Alcoholic)
• 5Elimination Several different ways. Kidney,
  feces, exhaled, breast milk, saliva, and/or
  sweat.

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Kidneys Role in Elimination

• 2 Ways Drugs are excreted by Kidneys
• 1Through the glomerulus
• Most common way.
• The drug which enters the tubule in this manner
  may be partially reabsorbed through the wall of
  the tubule back into the bloodstream.
• 2Through the walls of the tubules
• Secreted directly through the walls of the
  tubule. More rapid elimination.

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Common Pharmacokinetic Terms

• 1Onset The time after administration when the
  body initially responds to the drug.
• 2Peak Plasma Level The highest plasma level
  achieved by a single dose when the elimination
  rate of a drug equals the absorption rate.
• 3Drug Half-Life (Elimination half-life) The
  time required for the elimination process to
  reduce the concentration of the drug to one-half
  what it was at initial administration.

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Common Pharmacokinetic Terms

• 4Plateau A maintained concentration of a drug
  in the plasma during a series of scheduled doses.
• 5Loading Dose Bolus is administered to bring
  blood levels up to the therapeutic level quickly.

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Routes of Administration

• 1--Oral
• 2Sublingual
• 3Buccal
• 4Rectal
• 5Vaginal
• 6--Topical

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Still More Routes of Administration

• 7Transdermal
• 8Subcutaneous
• 9Intramuscular
• 10Intradermal

• 11Intravenous
• 12Inhalation
• 13Intrathecal An injection into the space
  around the spinal canal

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Monitoring Drug Therapy Results

• GOAL To achieve a therapeutic response
• 1 Assess patient Observe the client for
  desired effect and undesired toxic effects
• 2 Measure biochemical changes - Lab tests
• 3 Measure plasma concentrations of the drug
• Peak Greatest concentration of drug in body (30
  min after drug given IV)
• Trough Lowest level of drug concentration (30
  min. before next dose of drug to be given)

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Factors that Affect Response of Drug

• 1Age Extremes of age. Greater variations in
  drug absorption, distribution, biotransformation,
  and elimination.
• 2Gender Different body compositions
• 3Body weight More weighthigher dose needed.
• 4Body metabolic rate BMI to figure dosage
• 5Disease states may affect absorption,
  distribution, biotransformation, and excretion.
• 6Genetic factors

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More Factors

• 7Placebo effect Belief that therapy will work
• 8Time of administration Menstrual cycle, time of
  day, empty stomach
• 9Tolerance Considerable tolerance differences
• 10Environmental factors
• 11Idiosyncratic responses Unexpected and
  individual responses. Eg Drug not work or small
  amount is toxic.

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Drug Interactions and Incompatibilities

• All drugs are capable of reacting with other
  substances.
• Synergistically response greater that would be
  expected
• Antagonistically One drug diminishes the action
  of another
• Use compatibilities chart
• See Appendix 5pages 883

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Herbal/Botanical Medicine

• 1Not regulated by the FDA
• 2Are chemicals and have an influence on the
  body.
• 22--of pre-surgical clients reported using.
• Women and clients aged 40-60 years old were the
  most likely to use herbals
• Assess the patients use of herbs and document

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Teratogenic Effects of Agents

• Many drugs can have a teratogenic effect on an
  unborn fetus.
• Each drug has a pregnancy classification attached
  to it A through X
• Any good drug handbook will give the pregnancy
  classification of a drug and what each
  classification means.
• As a nurse it is important to check out the
  pregnancy classification of a drug before
  administering it to a woman of child-bearing age
• One of the nursing standards is do no harm

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Pregnancy Classifications

• ANo risk demonstrated to the fetus in any
  trimester
• BNo adverse effects in animalsno human studies
• COnly given after risks to the fetus
  consideredanimal studies show adverse reactions
• DDefinite fetal risks. Only given in life
  threatening situations
• XAbsolute fetal abnormalities

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Equivalents

• 60mg 1 grain
• 1 gram 1000 mg
• 1mcg 0.001 mg
• 1 tsp 5 ml
• 1 Tbsp 15 ml
• 1 kg 2.2

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Formula for Med Math

• Dosage Desired
• ________________ x Quantity X
• Dosage on Hand
• 300 mg/100mg X 2 ml _____ ml

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Abbreviations

• Be careful know but JACHO says to no longer use
  abbreviations -- should write out
• ac
• pc
• bid
• c
• cap
• disp

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More Abbreviations

• g or gm
• gr
• gtt
• h
• hs

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Still More Abbrevations

• po
• prn
• q
• qid
• s
• sig
• stat

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Just a Few More..

• tab
• tid