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INTRODUCTION TO
PHARMACOLOGY
Pharmacology Introduction
Outcomes
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Briefly discuss professional principles relevant to drug
administration
Briefly discuss ethical principles applied to drug
administration
Explain the nurses roles in ‘health education’ related to
medication
Define Pharmacology
Define Pharmacotherapuetics
Define Pharmacokinetics
Define Pharmacodynamics
Define the words drug and medicine
Outline the history of drug development
State four sources of drugs, giving one example from each
source
Explain drug names- giving one example from the BNF
Pharmacology Introduction
Outcomes
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State three different ways in which drugs work
(pharmacodynamics) giving examples of drugs
from each group.
Briefly explain what is meant by therapeutic range
Briefly explain why side effects may occur in
addition to ‘desired’ effects
Define and outline types of adverse drug reactions
State the role of the MHRA
List three types of drug interaction
Outline the stages of clinical trials
Case Example 1
Lauren (age 21years) was prescribed Clozapine whilst in hospital
to treat her schizophrenia.
She has been taking this medication for one year now and her
mental health has improved considerably. She has been discharged
from hospital (under Section 25) and is living in supported
accommodation near her mother.
Since staring on the medication she has experienced a number of
side effects. She feels tired much of the time, has gained 4 stone in
weight, is always constipated and has excessive saliva production
(hyper salivation) (she is too embarrassed to stay overnight at a
friend’s home).
Since she is feeling a lot better mentally, and is getting really fed
up with the side effects of her medication, she decides to stop
taking the Clozapine. She intends to discuss this with her CPN
when he next visits her (he is off sick at present and they have
been too short staffed to send anyone else!).
Discuss!!
Case example 2
Student nurse Helen was on her first clinical placement and
had been on the ward for a few days. She was asked by the
nurse in charge to give a patient (Mr Y) a suppository, as he
was complaining of constipation. She was instructed to use
the ‘PR’ tray from the clinical room. She followed the correct
procedure (as taught by the clinical teacher) with respect to
inserting the suppository (e.g. maintaining patient dignity,
ensuring correct patient position and effective
communication). The suppository was inserted and the
patient advised to ring for the nurse as soon as he needed
the toilet.
Half an hour passed and the patient expressed concern that
the suppository had not worked (at all) and this had never
been the case previously.
It transpired that the usual suppository (‘glycerin’) was not on
the PR tray and the student had used one called
‘aminophylline’.
Discuss!!
Case example 3
Mr Edwards (age 67) has had NIDDM for more than 15
years. Initially, his condition was controlled with diet
alone but for the last 5 years he has needed oral
hypoglycaemic agents. He attends all his GP and
diabetic clinic appointments and seems to be complying
with both diet and medication regimes.
He is a keen gardener lost confidence in going to his
garden alone as he has had a number of episodes of
nausea, sweating, tremors, dizziness and palpitations
that occur mostly in the late morning. His prescription
drugs have not been changed for a number of years and
he is not feverish, has no pain, nor is he exhibiting any
signs of illness other than these worrying episodes. His
main concern is that these symptoms will occur when
he is driving.
Discuss!
Case Example 4
Mr Edwards (Age 67–man diagnosed with NIDDM) also
has been medically managed for his hypertension for the
last 15 years has hypertension. He was taking an ACE
inhibitor to control his Hypertension was had now been
prescribed a Diuretic as well. He returned to talk to the
practice nurse to complain that his dizziness had
returned, particularly when he stood up and he had
actually stumbled with this a couple of times.
The Practice nurse reviewed his Blood pressure (lying
and standing) and noticed that at there was a
difference.
Discuss the advice you would offer Mt Edwards
Case Example 5
A doctor was deputising for a colleague absent on leave. After
a particularly demanding night, he was asked, in the early
hours of the morning, to see a premature infant with
congestive heart failure. He was not normally responsible for
the care of premature infants but he requested Digoxin to be
given intramuscularly and calculated (by mental arithmetic)
that the dose should be 0.6 mg.
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Just as he settled down for a restorative nap, the nurse phoned
to ask whether the dose shouldn’t be 0.06 mg as she had had
to open two ampoules.
Without thinking he told her to “give it as I ordered”. An hour
later, he was called to the ward because the baby had suffered
a cardiac arrest.
Discuss!!
http://www.medicalprotection.org/uk/booklets/common-problems-hospital/prescribing-for-children accessed 20/08/2012
‘Justification for study’
The nurse with
knowledge and
understanding of
pharmacology will be
more confident in drug
administration
Who is responsible for ‘health education’ with
respect to medication?
What professional principles are relevant?
What ethical principles can be applied to the
issue of patients being educated about their
medication?
Some Clinical Practice Considerations
The patient may ask:
How quickly will the drug work? (e.g. analgesic)
Do I take the tablets with food or on an empty
stomach? (e.g. antibiotics)
Can I take my other tablets (OTC medication) with
the medicine I have been prescribed? (e.g. aspirin)
Does it matter if I take the tablets at different times?
(e.g. antibiotics)
The nurse needs to be able to give the patient accurate
information and ‘empower’ the patient to be able to
self medicate
‘Justification’
King RL (2004) Nurses’ perceptions of their pharmacology
educational needs Journal of Advanced Nursing45(4), 392–400
Background:
Lack of science teaching in nurse education
Theory–practice gap in this area of the curriculum
Findings:
Limited understanding of the subject
Dissatisfaction with the teaching of pharmacology,
Resulting anxiety on qualifying
Conclusion:
Nurses have a limited understanding of pharmacology
They recognize the need for pharmacology knowledge
in practice.
Improved pharmacology teaching might increase
nurses’ confidence in: drug administration + patient
education, and decrease anxieties related to these roles
‘Justification’
Latter S Rycroft-Malone J Yerrell P Shaw D (2000)
Evaluating educational preparation for a health education
role in practice: the case of medication education
Current health care policy highlights the importance of
nurses contributing to educating patients about
medication.
Findings (of the study) highlighted the importance of:
* sufficient taught pharmacology
* an evidence-based curriculum
* practice-based learning
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J Adv Nurs. 2000 Nov;32(5):1282-90.
The NMC (2008) Medicine Management guidelines directs
us all to address our Knowledge and competence for safe
medicines storage and administration.
‘Justification’
The Impact of Drug Errors
Patients, their relatives and professionals
can experience considerable trauma and
there can be a substantial additional cost
to the NHS
(Armitage 2004)
Appropriate (and Inappropriate) use of
drugs
Drugs are used to:
* Cure or Arrest DISEASE
* Relieve SYMPTOMS
* Obtain a DIAGNOSIS
* PREVENT disease occurring
(Some situations when they should NOT be
used: To make the patient ‘easier to manage’!
When they will do more harm than good)
Nurses need knowledge of pharmacology
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Nurses need to:
Obtain drug HISTORIES
ASSESS patients taking drugs
ADMINISTER drugs
EDUCATE patients
MONITOR, record, evaluate and
REPORT patient responses to drugs
AND … counsel patients having drug rehabilitation
Science of Pharmacology
Pharmacology
Science (logos) of drugs
(pharmakon)
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PharmacoTHERAPEUTICS
= use of drugs to treat
disease
Assessment
Implementation
Monitoring and
Reassessment/evaluation
Science of Pharmacology
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PharmacoKINETICS = Absorption,
distribution, metabolism & excretion of
drugs (what the body does to the drug)
PharmacoDYNAMICS = Biochemical &
physical effects of drugs; Mechanisms
of drug action (what the drug does to
the body)
TOXICOLOGY = toxicity & adverse
effects of drugs
Drugs and Medicines
A DRUG is any chemical (except food) that will
bring about a response in the body
* All drugs are TOXIC (potentially)
* All drugs produce SIDE EFFECTS
* Interactions can occur between drugs (or
between drugs and food)
A MEDICINE is a drug that has
been ‘modified’ so that it is
suitable for administration
The (very brief!) History of Pharmacology
Oldest Science (originally a brand of magic!)
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Opium used for thousands of years
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Samuel Dale (London) catalogued existing knowledge
of drugs
 Descriptive Pharmacopoeia
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Early in 19th Century began experiments to establish
WHY drugs worked (beginning of real pharmacology)
Discoveries of the 19th Century include:
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1842 ether 1847 chloroform
History of Pharmacology
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Some key discoveries of the 20th
Century:
1922 Insulin
1941 Penicillin (first treatment)
1952 Chlorpromazine
1957 Benzodiazepine derivatives
1958 Haloperidol
1961-1967 Levodopa
Sources of drugs / medicines
Plant products or Plants:
Fox Glove
DIGOXIN
Poppy
OPIUM
Belladonna
ATROPINE
Coffee
CAFFEINE
Tobacco
NICOTINE
Animal products
Premarin (conjugated
Oestrogen) from Pregnant
Mares
Insulin from pigs & cows
Heparin from pigs & cows
Inorganic compounds
(compounds with no Carbon)
* Zinc + Sulphate ions
 Zinc Sulphate (Calamine
lotion)
* Aluminium +Hydroxyl
 Aluminium hydroxide
* KCl
Synthetic sources
Drugs made in LABORATORY
Most drugs today made in labs = safer
Many drugs are synthetic copies of
naturally occurring substances e.g.
steroids
Insulin (biosynthetic human
insulin / recombinant or DNAderived insulin)
Plasmid from E coli cell
Plasmid opened by an enzyme
Human insulin gene
inserted
Recombination (new insulin gene
+ plasmid)
Cell division
 cells produce
human insulin
Recombined plasmid put into
host E Coli cell
Drug Names
Chemical
Describes actual
Compound
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Generic
Official Medical
name for active
substance
Brand Name
Name chosen by
manufacturer
DIAZEPAM
SODIUM
VALPROATE
VALIUM
EPILIM
Pharmacodynamics
Involves study of the effects of the drug in the
body & its mechanisms of action
What Drugs Do
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REPLACE natural body substances
 E.g. thyroxine, insulin
Act against ABNORMAL cells or invading
ORGANISMS
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E.g. chemotherapeutic agents, antibiotics
What Drugs Do
Interfere with cell FUNCTION
 Act at RECEPTOR SITES
 intensifying cell activity (agonists)
or
 reducing activity (antagonists)
Clozapine administration was found to produce
dopamine2 (D-2) and serotonin2 (5-HT2) receptor
blockade’
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Inhibit ENZYMES
 neostigmine inhibits cholinesterase
Therapeutic Effect
Dose
THERAPEUTIC RANGE
Time
Side Effects
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A drug, once absorbed to the circulation, will be
distributed throughout the body  affecting
other parts  SIDE EFFECTS
Examples
Drug
Side effect
Clozapine
Constipation, Hyper salivation,
Iron
Constipation, Nausea
Codeine
Constipation
Morphine
Constipation
Adverse Reactions
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‘Any response to a drug which is noxious,
unintended and occurs at doses used in man
for prophylaxis, diagnosis or therapy’
 ADVERSE REACTION (WHO)
Adverse reactions:
* may be due to ALLERGY or GENETIC absence
of specific enzymes
* may be predictable or unpredictable
* may be TERATOGENIC (causing embryonic
deformities)
* are IATROGENIC (caused by practitioners)
The Medicines and Healthcare products
Regulatory Agency (MHRA)
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The Medicines and Healthcare products Regulatory Agency
(MHRA) is the government agency which is responsible for
ensuring that medicines and medical devices work, and are
acceptably safe.
• The MHRA website http://mhra.gov.uk
SUSPECTED ADVERSE DRUG REACTIONS
If you are suspicious that an adverse reaction may be
related to a drug or combination of drugs please complete
this Yellow Card.
PATIENT DETAILS
SUSPECTED DRUG(S)
SUSPECTED REACTION(S)
OUTCOME
OTHER DRUGS (including self-medication & herbal
remedies)
Additional relevant information
The MHRA
REGULATES:
Controlled substances
EXAMPLES:
Opiates
Generic
/ proprietary drugs
Paracetamol
Orphan
drugs
Rare diseases/small
populations
Over-the-counter
Prescription
Nurse
(OTC) drugs
Paracetamol
Only Medicines (POM)Warfarin
Prescriber’s Extended
Formulary
Minor ailments, minor
injuries, health
promotion
& palliative care
Drug Interactions
These interactions may be beneficial or harmful
and include:
Alterations in ABSORPTION
Altered METABOLISM of other drugs
Competition for RECEPTORS
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Some important interactions:
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Oral anticoagulants and aspirin
Development of new drugs
Preclinical trials
New drugs or treatment approaches :
often tested first on animals (or live
human cells in test tubes).
Scientists identify an approach that is most
likely to succeed, and then carry out
preliminary research into safety and
effectiveness.
Phase 1 studies: Early Clinical Trials
These first trials usually involve a
small number of individuals (less
than 100) who are healthy.
However …
there are times when the new
compound is tested first in people
who have the condition that the
drug is meant to treat
(especially when the drug is meant
to treat a very serious disease and
The objective=
is likely to have serious side
to find out if the
effects).
new drug is safe.
Phase 2 Continuing Clinical Trials
If the new compound is considered safe on
animals, testing is expanded to see if it is
effective,
Trials include people who
have the disease or
Condition against which
the researchers think a
new compound will be
effective.
Phase 3 studies
A drug is tested in several
hundred to several
thousand subjects.
This large-scale testing provides more
information about:
*the drug's effectiveness,
*possible side effects, and
*safety in a broader range of people.
Drug Trials
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Recall that Six men were treated in intensive care
after experiencing a serious reaction to a drug taken
during a clinical drugs trial in north-west London in
2006
The six healthy men, all under 40, had volunteered to take part in a trial of an
anti-inflammatory drug, to treat conditions such as rheumatoid arthritis and
leukaemia, being tested at an independent research unit based at Northwick
Park Hospital.
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The six suffered multiple organ failure, and two were said to be critically ill. Another two
men, who had been given a dummy version of the drug in the trial, did not fall ill.
The trial was stopped as soon as the men fell ill.
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http://news.bbc.co.uk/1/hi/england/london/4807042.stm
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Accessed 20/08/2012
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Drug trials also don’t always bring about
what they are expected to do – The sceince
does not work out:
http://www.wired.co.uk/magazine/archive/2012/02/features/trials-
and-errors accessed 07/11/2013
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‘Homework’!
–
Check the ingredients of four or five different OTC
drugs for comparison and to familiarize yourself with
the difficulty a layperson may encounter while trying
to find this information.
Give rationale for why some drugs need to be kept
under lock and key on the hospital unit. Discuss this
with your mentor.
Familiarize yourself with 4 or 5 drugs that are often
prescribed & administered in your placement setting.
Outline the role of the nurse in the safe administration
of these drugs. Discuss this with your mentor & your
clinical teacher.