Introduction to pharmacology for nursing students

1. Mrs.Nagamani.T
MSc (N)

2. Objective
 Upon completion of the topic the health care
professionals understands the importance of safe
administration of medications and appreciate the
knowledge about the actions and effects of
medications to safely and accurately administer
medications and understands about pharmacologic
principles.

3. Contents
Introduction to pharmacology
 Definitions
 Sources
 Terminology used
 Types: Classification
 Pharmacodynamics: Actions, therapeutic
 Adverse, toxic
 Pharmacokinetics : absorption, distribution, metabolism,
interaction, excretion
 Review: Routes and principles of administration of drugs
 Indian pharmacopoeia : Legal issues
 Rational use of drugs
 Principles of therapeutics

4. Introduction
 Pharmacology is the study of drugs including their
origins, history, uses, and properties.
 The word pharmacology comes from the Greek
words pharmakos, meaning medicine or drug,
and logos, meaning study.
 Drug therapy plays a major role in the treatment of
patients.
 It involves the use of drugs to prevent, diagnose or cure
disease processes or to relieve signs and symptoms
without curing the underlying disease.

5. Definitions
 Pharmacology is the scientific study of the effects of
drugs and chemicals on living organisms where a drug
can be broadly defined as any chemical substance,
natural or synthetic, which affects a biological system.
 Pharmacology is the science that deals with the study
of drugs and their interactions with the living system.
 Pharmacology is the science that deals with drugs,
their sources, nature and properties.

6. Sources of drugs
 Drugs are substances that are used or intended to be used in the diagnosis, prevention,
treatment or cure of diseases.
 The major sources of drugs can be grouped into the following;
1. Plant Sources
plant source for drugs are the leaf and other parts of plants (e.g., barks, fruits, roots, stem, wood,
seeds, blossoms, bulb etc.)
Plant part Drugs
Leaves Digoxin, digitoxin (from Digitalis purpurea/foxglove plant);
atropine (from Atropa belladonna)
Flowers Vincristine, vinblastine (from Vinca rosea)
Fruits Physostigmine (from Physostigma venenosum/calabar bean)
Seeds Strychnine (from Nux vomica); physostigmine
(from Physostigma venenosum/calabar bean)
Roots Emetine (from Cephaelis ipecacuanha); reserpine (from Rauwolfa
serpentina)
Bark Quinine (from Cinchona); atropine (from Atropa
belladonna)
Stem Tubocurarine (from Chondrodendron tomentosum)

7.  2. Animal Sources
Medicinal substances are derived from the animal’s body
secretions, fluid or glands. Insulin, heparin, adrenaline,
thyroxin, cod liver oil, musk, beeswax, enzymes, and
antitoxins sera are some examples of drugs obtained
from
animal sources.
3. Microbial sources
Several life-saving drugs have been historically derived
from microorganisms. Examples include penicillin
produced by Penicillium chrysogenum, streptomycin
from Streptomyces griseus, chloramphenicol
from Streptomyces venezuelae, neomycin
from Streptomyces fradiae, bacitracin from Bacillus
subtilis etc.

8. 4. Marine source
 Bioactive compounds from marine flora and fauna have extensive past
and present use in the prevention, treatment or cure of many diseases.
Coral, sponges, fish, and marine microorganisms produce biologically
potent chemicals with interesting anti-inflammatory, anti-viral, and
anticancer activity.
5. Mineral sources
 Minerals (both metallic and non-metallic minerals) have been used as
drugs since ancient times. Examples include ferrous sulfate in iron
deficiency anemia; magnesium sulfate as purgative; magnesium
trisilicate, aluminum hydroxide and sodium bicarbonate as antacids for
hyperacidity and peptic ulcer; zinc oxide ointment as skin protectant,
in wounds and eczema; gold salts (solganal, auranofin) as anti-
inflammatory and in rheumatoid arthritis; selenium as anti-dandruff.

9. 6. Synthetic/chemical derivative
A synthetic drug is produced using chemical synthesis,
which rearranges chemical derivatives to form a new
compound.
Examples include acetylsalicylic acid (aspirin or ASA),
oral antidiabetics, antihistamines, thiazide diuretics,
chloroquine, chlorpromazine, general and local
anaesthetics, paracetamol, phenytoin etc.

10. 7. Semi-synthetic Sources
 Semi-synthetic drugs are neither completely
natural nor completely synthetic. They are a hybrid
and are generally made by chemically modifying
substances that are available from natural source to
improve its potency, efficacy and/or reduce side
effects.
 Examples of semi-synthetic medicine include
heroin from morphine, bromoscopolamine from
scopolamine, homatropine from atropine,
ampicillin from penicillin etc.

11. 8. Biosynthetic sources (genetically engineered
drugs)
This is relatively a new field which is being developed
by mixing discoveries from molecular biology,
recombinant DNA technology, DNA alteration,
gene splicing, immunology, and immune
pharmacology.
Drugs developed using living organisms with the
help of biotechnology or genetic engineering are
known as biologics, biopharmaceuticals,
recombinant DNA expressed products,
bioengineered, or genetically engineered drugs
Examples include recombinant Hepatitis B vaccine,
recombinant insulin and others.

13. Drug Names
Chemical name
• Describes the drug’s chemical composition and molecular
structure
Generic name (nonproprietary name)
• Name given by the United States Adopted
Name Council
Trade name (proprietary name)
• The drug has a registered trademark; use of the name
restricted by the drug’s patent owner
(usually the manufacturer)

14. Drug Names (cont'd)
Chemical name
• (+/-)-2-(p-isobutylphenyl) propionic acid
Generic name
• ibuprofen
Trade name
• Motrin®, Advil®

15. Pharmacological Concepts:
Classification
 Classification- Nurses learn to categorize meds
with similar characteristics by their class
 Medication classification indicates the effect of the
med on the body system, the symptom the med
relieves, or the med’s desired effect (e.g. oral
hypoglycemics)

16. Pharmacological Concepts:
Classification
 A medication may also be part of more than one class
 Aspirin is an analgesic, antipyretic, anti-inflammatory,
and anti-platelet

17. Pharmacological concepts: Medication forms
 Medications are available in a variety of forms and
preparations
 The form of the med will determine its route of
administration
 Composition of med is designed to enhance its
absorption & metabolism
 Many meds are available in several forms

18. Medication Forms
 Tablet
 Capsule
 Elixir
 Enteric-coated
 Suppository
 Suspension
 Transdermal patch

19. Pharmacologic Principles
• Pharmaceutics
• Pharmacokinetics
• Pharmacodynamics
• Pharmacotherapeutics
• Pharmacognosy

20. Pharmaceutics
The study of how various drug forms influence
pharmacokinetic and pharmacodynamic activities

21. Pharmacokinetics
• The study of what the body does to the drug
– Absorption
– Distribution
– Metabolism
– Excretion

22. Pharmaco dynamics
• The study of what the drug does to the body
– The mechanism of drug actions in living
tissues

23. Figure 2-2 Phases of Drug Activity. (From
McKenry LM, Salerno E: Mosby’s
pharmacology in nursing—revised and
updated, ed 21, St. Louis, 2003, Mosby.)

24. Pharmacotherapeutics
The use of drugs and the clinical
indications for drugs to prevent
and treat diseases

25. Pharmacognosy
The study of natural (plant and animal) drug sources

26. Pharmacokinetics: Absorption
• The rate at which a drug leaves its site of
administration, and the extent to which absorption
occurs
– Bioavailability
– Bioequivalent

27. Factors That Affect Absorption
• Administration route of the drug
• Ability of Med to Dissolve
• Food or fluids administered with the drug
• Body Surface Area
• Status of the absorptive surface
• Rate of blood flow to the small intestine
• Lipid Solubility of Med
• Status of GI motility

28. Routes of Administration
• A drug’s route of administration affects the rate and
extent of absorption of that drug
– Enteral (GI tract)
– Parenteral
– Topical

29. Enteral Route
• Drug is absorbed into the systemic circulation through
the oral or gastric mucosa, the small intestine, or
rectum
– Oral
– Sublingual
– Buccal
– Rectal

30. Parenteral Route
• Intravenous (fastest delivery into the blood
circulation)
• Intramuscular
• Subcutaneous
• Intradermal
• Intrathecal
• Intraarticular

31. Topical Route
• Skin (including transdermal patches)
• Eyes
• Ears
• Nose
• Lungs (inhalation)
• Vagina

32. Distribution
The transport of a drug in the body by the
bloodstream to its site of action
• Protein-binding
• Water soluble vs. fat soluble
• Blood-brain barrier
• Areas of rapid distribution: heart, liver,
kidneys, brain
• Areas of slow distribution: muscle, skin, fat

34. Metabolism
(Also Known As Biotransformation)
The biologic transformation of a drug into
an inactive metabolite, a more soluble compound,
or a more potent metabolite
• Liver (main organ)
• Kidneys
• Lungs
• Plasma
• Intestinal mucosa

35. Metabolism/Biotransformation
(cont'd)
Delayed drug metabolism results in:
• Accumulation of drugs
• Prolonged action of the drugs
Stimulating drug metabolism causes:
• Diminished pharmacologic effects

36. Excretion
The elimination of drugs from the body
• Kidneys (main organ)
• Liver
• Bowel
– Biliary excretion
– Enterohepatic circulation

37.  1. You are caring for a client who has diabetes complicated by kidney
disease. You will need to make a detailed assessment when administering
medications because this client may experience problems with:
 A. Absorption
 B. Biotransformation
 C. Distribution
 D. Excretion
35 - 37

38. Pharmacodynamics
 Study of the mechanism of drug actions in living
tissue
 Drug-induced alterations to normal physiologic
function
 Positive change-Therapeutic effect-Goal of therapy

39. Mechanism of Action
 Ways in which a drug can produce a therapeutic effect
 The effects that a particular drug has depends on the
cells or organ targeted by the drug
 Once the drug hits its “site of action” it can modify the
rate at which a cell or tissue functions

40. Mechanism of Action
 Receptor Interaction
 Enzyme Interaction
 Non-Specific Interaction

41. Receptor Interaction
 Drug structure is essential
 Involves the selective joining of drug molecule
with a reactive site on the cell surface that elicits a
biological effect
 Receptor is the reactive site on a cell or tissue
 Once the substance binds to and interacts with the
receptor, a pharmacologic response is produced

42. Receptor Interaction
 Affinity- degree to which a drug binds with a
receptor
 The drug with the best “fit” or affinity will elicit the
best response
 Drug can mimic body’s endogenous substances
that normally bind to receptor site
 Drugs that bind to receptors interact with
receptors in different ways to either block or elicit a
response

43. Receptor Interaction
 Agonist-Drug binds to receptor-there is a response
(Adrenergic Agents)
 Antagonist-drug binds to receptor-no response-
prevents binding of agonists (Alpha & Beta Blockers)

45. Enzyme Interaction
 Enzymes are substances that catalyze nearly every
biochemical reaction in a cell
 Drugs can interact with enzyme systems to alter a
response
 Inhibits action of enzymes-enzyme is “fooled” into
binding to drug instead of target cell
 Protects target cell from enzyme’s action (ACE
Inhibitors)

46. Non-Specific Interaction
 Not involving a receptor site or alteration in
enzyme function
 Main site of action is cell membrane or cellular
process
 Drugs will physically interfere or chemically alter
cell process
 Final product is altered causing defect or cell death
 Cancer drugs, Antibiotics

48. The nurse is giving a medication that has a
high first-pass effect. The physician has
changed the route from IV to PO. The nurse
expects the oral dose to be:
1. Higher because of the first-pass effect.
2. Lower because of the first-pass effect.
3. The same as the IV dose.
4. Unchanged.

49. . A patient is complaining of severe pain and
has orders for morphine sulfate. The nurse
knows that the route that would give the
slowest pain relief would be which route?
1. IV
2. IM
3. SC
4. PO

50. Type of Medication Action
 Therapeutic Effect
 Side Effects
 Adverse Effects
 Toxic Effect
 Idiosyncratic Reactions
 Allergic Reaction
 Medication Interactions
 Iatrogenic Response

51. Therapeutic Effect
 The expected or predictable physiological response a
medication causes
 A single med can have several therapeutic effects
(Aspirin)
 It is important for the nurse to know why med is being
prescribed

52. Side Effects
 Unintended secondary effects a medication
predictably will cause
 May be harmless or serious
 If side effects are serious enough to negate the
beneficial effect of meds therapeutic action, it may
be D/C’d
 People may stop taking medications because of the
side effects

53. Adverse Effects
 Undesirable response of a medication
 Unexpected effects of drug not related to
therapeutic effect
 Must be reported to FDA
 Can be a side effect or a harmful effect
 Can be categorized as pharmacologic,
idiosyncratic, hypersensitivity, or drug interaction

54. Adverse Effects
 Adverse Drug Events
 Adverse Drug Reactions (ADR)

55. Toxic Effect
 May develop after prolonged intake or when a med
accumulates in the blood because of impaired
metabolism or excretion, or excessive amount
taken
 Toxic levels of opioids can cause resp.depression
 Antidotes available to reverse effects

56. Idiosyncratic Reactions
 Unpredictable effects-overreacts or under reacts to
a medication or has a reaction different from
normal
 Genetically determined abnormal response
 Idiosyncratic drug reactions are usually caused by
abnormal levels of drug-metabolizing enzymes
(deficiency or overabundance)

57. Allergic Reaction
 Unpredictable response to a medication
 Makes up greater than 10% of all medication
reactions
 Client may become sensitized immunologically to
the initial dose, repeated administration causes an
allergic response to the med, chemical preservative
or a metabolite

58. Allergic Reaction
 Medication acts as an antigen triggering the
release of the body’s antibodies
 May be mild or severe
 Among the different classes of meds, antibiotics
cause the highest incidence of allergic reaction
 Severe reaction-Anaphylactic reaction
 Mild reaction-hives, rash, pruritis

62.  2. A postoperative client is receiving morphine sulfate via a
PCA. The nurse assesses that the client’s respirations are
depressed. The effects of the morphine sulfate can be classified as:
 A. Allergic
 B. Idiosyncratic
 C. Therapeutic
 D. Toxic
35 - 62

63. Other Drug Reactions
 Teratogenic-Structural effect in unborn fetus
(thalidomide)
 Carcinogenic-Causes cancer
 Mutagenic- Changes genetic composition (radiation,
chemicals)

64. Drug Interactions
 Occurs when one med modifies the action of another
 Common in people taking several medications at once
 One med may potentiate or diminish the action of
another or alter the way it is absorbed, metabolized or
eliminated
 Warfarin and Amiodarone

65. Iatrogenic Responses
 Unintentional adverse effects that occur during
therapy
 Treatment-Induced Dermatologic-rash, hives,
acne
 Renal Damage-Aminoglycoside antibiotics,
NSAIDS, contrast medium
 Blood Dyscrasias- Destruction of blood cells
(Chemotherapy)
 Hepatic Toxicity-Elevated liver enzymes (hepatitis-
like symptoms)

66. Synergistic Effect
 Effect of 2 meds combined is greater than the
meds given separately
 Alcohol & Antihistamines, antidepressants,
barbiturates, narcotics
 Not always undesirable, physician may combine
meds to create an interaction that will have
beneficial effects (Vasodilators & diuretics to
control high BP)

67. Medication Dose Responses
 Except when administered IV, meds take time to
enter bloodstream
 The quantity & distribution of med in different
body compartments change constantly
 Goal is to keep constant blood level within a safe
therapeutic range
 Repeated doses are required to achieve a constant
therapeutic concentration of a med because a
portion of med is always being excreted

68. Medication Dose Responses
 Serum Half-Life:Time it takes for excretion
processes to lower the serum medication
concentration by ½
 Regular fixed doses must be given to maintain
therapeutic concentration
 Dosage schedules set by institutions (TID, q8h,
HS, AC, STAT, PRN)
 Peak & Trough levels
 Therapeutic drug monitoring

69. Half-life
• The time it takes for one half of the original
amount of a drug in the body to be removed
• A measure of the rate at which drugs are removed
from the body

70. Onset, Peak, and Duration
Onset
• The time it takes for the drug to elicit a
therapeutic response
Peak
• The time it takes for a drug to reach its
maximum therapeutic response
Duration
• The time a drug concentration is sufficient to
elicit a therapeutic response

71. Pharmaco therapeutics: Types of
Therapies
• Acute therapy
• Maintenance therapy
• Supplemental therapy
• Palliative therapy
• Supportive therapy
• Prophylactic therapy
• Empiric therapy

72. Monitoring
• The effectiveness of the drug therapy must be
evaluated
• One must be familiar with the drug’s:
– Intended therapeutic action (beneficial)
– Unintended but potential side effects (predictable,
adverse reactions)

73. Monitoring (cont'd)
• Therapeutic index
– The ratio between a drug’s therapeutic
benefits and its toxic effects

74. Monitoring (cont'd)
• Tolerance
– A decreasing response to repetitive drug doses

75. Monitoring (cont'd)
• Dependence
– A physiologic or psychological need for a drug

76. Monitoring (cont'd)
Interactions may occur with other drugs or food
• Drug interactions: the alteration of action of
a drug by:
– Other prescribed drugs
– Over-the-counter medications
– Herbal therapies

77. Monitoring (cont'd)
• Drug interactions
– Additive effect
– Synergistic effect
– Antagonistic effect
– Incompatibility

78. Monitoring (cont'd)
• Medication misadventures
– Adverse drug events
– Adverse drug reactions
– Medication errors

79. Monitoring (cont'd)
Some adverse drug reactions are classified as side
effects
• Expected, well-known reactions that result in little
or no change in patient management
• Predictable frequency
• The effect’s intensity and occurrence are related to
the size of the dose

80. Adverse Drug Reaction
An adverse outcome of drug therapy in which a patient
is harmed in some way
• Pharmacologic reactions
• Idiosyncratic reactions
• Hypersensitivity reactions
• Drug interactions

81. Other Drug-Related Effects
• Teratogenic
• Mutagenic
• Carcinogenic

82. Toxicology
The study of poisons and unwanted responses to
therapeutic agents

83. Table 2-9 Common
Poisons and Antidotes

84. INDIAN PHARMACOPOEIA
 The Indian Pharmacopoeia (IP) is a compilation of
official standards for drugs manufactured in India.
 Standards in the IP are expressed in the form of
specifications and test methods for determining
compliance with such standards.
 The pharmacopoeias or formularies contain a list of
drugs and other related substances regarding their
source, descriptions, standards, tests, formulae for
preparing the same, action and uses, doses, storage
conditions etc

85.  Indian Pharmacopoeia (IP) is published by the Indian
Pharmacopoeia Commission (IPC) on behalf of the
Ministry of Health & Family Welfare, Government of India
in fulfillment of the requirements of the Drugs and
Cosmetics Act, 1940 and Rules 1945 there under.
 IP is recognized as the official book of standards for the
drugs being manufactured and/or marketed in India. IP
contains a collection of authoritative procedures of analysis
and specifications of drugs for their identity, purity and
strength.
 The standards of the IP are authoritative in nature and are
enforced by the regulatory authorities for ensuring the
quality of drugs in India. During quality assurance and at
the time of dispute in the court of law the IP standards are
legally acceptable.

86.  1946- Indian Pharmacopoeial List was published by Govt. of
India.
 1955 -First edition of Indian Pharmacopoeia was published.
 1960 -Supplement of IP 1955 was published.
 1966 - Second edition of IP was published.
 1975 -Supplement of IP 1966 was published.
 1985- Third edition of IP was published.
 1989 -Addendum-I to IP 1985 was published.
 1991 -Addendum-II to IP 1985 was published.
 1996 -Fourth edition of IP was published followed by its
addendum 2000, supplement 2000 for Veterinary Products,
addendum 2002 and addendum 2005;
 Indian Pharmacopoeia 2007 - Fifth edition, followed by
addendum 2008;
 Indian Pharmacopoeia 2010 - Six edition with DVD followed by
its addendum 2012;
 Indian Pharmacopoeia 2014 – Seventh edition with DVD
followed by its addendum 2015 and addendum 2016;
 Indian Pharmacopoeia 2018 with DVD - Eighth edition

88. Medication Misadventures
• Medication errors (MEs)
• Adverse drug events (ADEs)
• Adverse drug reactions (ADRs)

89. Medication Misadventures
(cont'd)
• By definition, all ADRs are also ADEs
• But all ADEs are not ADRs
• Two types of ADRs
– Allergic reactions
– Idiosyncratic reactions

90. Medication Errors
• Preventable
• Common cause of adverse health care outcomes
• Effects can range from no significant effect to directly
causing disability or death

91. Box 5-1 Common classes of medications
involved in serious errors

92. Preventing Medication Errors
• Minimize verbal or telephone orders
– Repeat order to prescriber
– Spell drug name aloud
– Speak slowly and clearly
• List indication next to each order
• Avoid medical shorthand, including abbreviations and
acronyms

93. Preventing Medication Errors
(cont'd)
• Never assume anything about items not
specified in a drug order (i.e., route)
• Do not hesitate to question a medication order
for any reason when in doubt
• Do not try to decipher illegibly written orders;
contact prescriber for clarification

94. Preventing Medication Errors
(cont'd)
• NEVER use “trailing zeros” with medication orders
• Do not use 1.0 mg; use 1 mg
• 1.0 mg could be misread as 10 mg, resulting in a
tenfold dose increase

95. Preventing Medication Errors
(cont'd)
• ALWAYS use a “leading zero” for decimal dosages
• Do not use .25 mg; use 0.25 mg
• .25 mg may be misread as 25 mg
• “.25” is sometimes called a “naked decimal”

96. Preventing Medication Errors
(cont'd)
• Check medication order and what is available while
using the “5 rights”
• Take time to learn special administration techniques of
certain dosage forms

97. Preventing Medication Errors
(cont'd)
• Always listen to and honor any concerns expressed by
patients regarding medications
• Check patient allergies and identification
• Medication Reconciliation

98. Medication Errors
• Medication error has the potential to lead to harm to the
patient. It is the leading cause of threatens trust in the
healthcare system, induce corrective therapy, and prolong
patients’ hospitalization, produces extra costs and even
death.
• Possible consequences to nurses
• Reporting and responding to MEs
– ADE monitoring programs
– USPMERP (United States Pharmacopeia Medication Errors
Reporting Program)
– MedWatch, sponsored by the FDA
– Institute for Safe Medication Practices (ISMP)
• Notification of patient regarding MEs

99. 3. Nurses are legally required to document medications that are
administered to clients. The nurse is mandated to document:
A. Medication before administering it
B. Medication after administering it
C. Rationale for administering the medication
D. Prescriber’s rationale for prescribing the medication
35 - 99

100. 4. If a nurse experiences a problem reading a physician’s medication
order, the most appropriate action will be to:
A. Call the physician to verify the order.
B. Call the pharmacist to verify the order.
C. Consult with other nursing staff to verify the order.
D. Withhold the medication until the physician makes rounds.
35 - 100

101. Administer medications safely