Preface
ix
Links to
Laerdal clinical simulations
enable students
to link theory to practice, prepare for clinical placement
and acquire the knowledge and skills essential for pro-
fessional practice.
5.
Outline care considerations for people receiving each class of antibiotic.
Glossary of key terms
aerobic:
bacteria that depend on oxygen for survival
anaerobic:
bacteria that survive without oxygen, which are often seen when blood flow is cut off to an area of the body
antibiotic:
chemical that is able to inhibit the growth of specific bacteria or cause the death of susceptible bacteria
gram-negative:
bacteria that accept a negative stain and are frequently associated with infections of the genitourinary or GI tract
gram-positive:
bacteria that take a positive stain and are frequently associated with infections of the respiratory tract and soft tissues
synergistic:
drugs that work together to increase drug effectiveness
Test your curr nt knowledge of antibiotics with a PrepU Practice Quiz!
Simulation-based learning
On completion of the chapter, explore the scenario of Kenneth Bronson (Part 1) who has been diagnosed with a strep
throat. Continue onto the second scenario (Part 2) as his condition deteriorates into an emergency situation. Consider
the medication management of Kenneth’s condition throughout his episode of care. What learning from the chapter,
can be applied to the case?
AMINOGLYCOSIDES
amikacin
framycetin
gentamicin
neomycin
tobramycin
CARBAPENEMS
doripenem
ertapenem
imipenem-cilastatin
meropenem
CEPHALOSPORINS
First-generation
cefalotin
cephalexin
cephazolin
Second-generation
cefaclor
cefoxitin
cefuroxime
Third-generation
cefotaxime
ceftazidime
ceftriaxone
Fourth-generation
cefepime
Fifth-generation
ceftaroline
FLUOROQUINOLONES
ciprofloxacin
moxifloxacin
norfloxacin
ofloxacin
PENICILLINS AND
PENICILLINASE-RESISTANT
ANTIBIOTICS
Penicillins
benzathine penicillin
benzylpenicillin
Icons for
Concepts in action
animations depicting
pharmacological concepts,
Watch and learn
video clips,
Practice and learn
activities and clinical simulation case
studies guide students to online resources to further
enhance understanding of complex topics.
ered to it by a series of liver
reak the drug into metabo-
tive and cause effects in the
are deactivated and can be
lt, a large percentage of the
his point and never reaches
on is known as the
first-pass
drug that gets through the
to the circulatory system for
dy.
gs absorbed from sites other
a similar biotransformation
e liver. Because some of the
a chance to reach the respon-
the liver, the injected drug is
er dose than the oral equiva-
d dose for oral drugs can be
e recommended dose for par-
st-pass effect into account.
valence
e proportion of drug that
circulation after oral admin-
ount both absorption and
lates to the total proportion
stemic circulation. The use
bility is limited as it relates
of the drug that reaches the
glects the rate of absorption.
e decisions about the “generic
roducts. The concept of bio-
provide evidence that a new
y similar to the existing one
ut causing clinical problems
ovement of a drug to the
As with absorption, factors
include the drug’s lipid solu-
e perfusion of the responsive
rfusion is a factor in caring
who has a lower-leg infec-
o destroy the bacteria in the
drugs may not be effective
process involves changes in
ed blood flow to some areas,
bs. If there is not adequate
e antibiotic can be delivered
iotic effect will be seen.
therapeutic effect from drugs intended to react with
those tissues.
Many drugs are bound to proteins and are not lipid
soluble. These drugs cannot be distributed to the central
nervous system (CNS) because of the effective blood–
brain barrier (see later discussion), which is highly
selective in allowing lipid solubl substances to pass into
the CNS.
Pharmacology:
Di tr bution
Protein binding
Most drugs are bound to some extent to proteins in the
blood to be carri d into circulation. The protei –drug
complex is relatively large and c nnot enter into capil-
laries and then into tissues to react. The drug m st be
freed from the protein’s binding site at the tissues.
Many drugs are extensively bound to proteins and
it should be noted that only the unbound fraction of the
drug can reach the site of action in responsive tissues.
Some drugs compete with each other for protein binding
sites, al ering effectiveness or causing toxicity wh n the
two drugs are given together. The toxicity is attributed
to sudden increase in the fraction of the previously pro-
tein-bound drug that is now free.
Pharmacology:
Drug binding
Blood–brain barrier
The blood–brain barrier is a protective system of cellular
membranes that keep many things (e.g. foreign invaders,
poisons) away from the CNS. The fundamental structural
difference of the membranes forming the blood-brain
barrier is the use of so called tight-junctions between
cells, leaving no gaps between the cells. Drugs that are
highly lipid soluble are more likely to pass through the
blood–brain barrier and reach the CNS. Drugs that are
not lipid soluble are not able to pass the blood–brain
barrier. This is clinically significant in treating a brain
infection with antibiotics. Almost all antibiotics are not
lipid soluble and cannot cross the blood–brain barrier.
Effective antibiotic treatment can occur only when the
infection is severe enough to damage the blood–brain
barrier and allow antibiotics to cross.
Although many drugs can cause adverse CNS
effects, these are often the result of indirect drug effects
and not the actual reaction of the drug with CNS tissue.
For example, alterations in glucose levels and electro-
lyte changes can interfere with nerve functioning and
produce CNS effects such as dizziness, confusion or
changes in thinking ability.
al changes that can
sed blood volume,
sorption, reduced
anges in receptor-
ten have a variety
can be receiving a
o be evaluated for
ith various central
heimer’s disease or
ficulty swallowing
dication. Through-
ross the Lifespan
to the drug class
fically to children,
. These boxes high-
ife should consider
each age group.
and set of interventions. H althcare priorities reflect
identified alterations in a person’s function based on
the assessment of the clinical situation. Because drug
therapy is nly a small part of the verall person’s situ-
ation, priorities that are related to drug therapy must be
incorporated into a total picture of the pers .
Implementation
nvolves taking th information
ga red and synthesised to plan care. This process
includes setting goals and desired outcomes to assure
safe and effective drug therapy. These outcomes usually
involve ensuring effective response to drug therapy,
minimising adverse effects and understanding the drug
regimen. Three types of interventions are frequently
involved in drug therapy: drug dministration, provision
of comfort easures and education of the person and
their family.
Proper drug administration
Nurses and midwives must consider a ser es of points,
or “rights”, t ensure safe and effective drug admin-
istration. These are correct drug and person, correct
storage of drug, correct and most effective route, corr ct
dose, correct preparation, correct timing and correct
ec r ing of admin s r i n. Se the later section on the
prevention of medication errors for a det iled xplana-
tion of the nurse’s and midwife’s role in implementing
these rights. Remembering to review each point before
administering a drug will help to prevent medication
errors and improve care outcomes.
Medications:
The Three Checks and the Five Ri hts
of Medication Administration
ion
r handbook
relation to the
ssment provides
before giving that
te the effects of
should supplement
ich include social,
ther factors.
T
he cardiovascular sy tem is a closed sys m of blood
vessels that is responsible for delivering oxy enated
bl od to the tissues an removing waste products from
the tiss es. The blood in this system flows from areas f
higher pressure to areas of lower pr ssure. The area of
highest pressure in th system is always e left ventri-
cle during systole. The pr ssure in this area p opel the
blood out of the aorta and into the system. The lowest
pressure is in the right atrium, which collects all of the
deoxygenated blood fr m the body. The maint nance
of this pressure system is controlled by specific areas of
the brain nd various hormones. If the pressure becomes
too high, t person is said to be hypertensive. If the
pressure becomes to low and blood cannot be delivered
effectively, the person is said to be hypotensive. Helping
the erson t maintain the blood pressure within ormal
limits is the oal of drug therapy. Cardiovascular health
is one of the Australia g vernment’s nine National
Health Priority Areas (AIHW, 2013).
Assessing blood pressure
REVIEW OF BLOOD PRESSURE CONTROL
The pressure in the cardiovascular system is determined
by three elements:
• Heart rate
•
Stroke volume
, or the amount of blood that is pumped
out of the ventricle with each heartbeat (primarily
determined by the volume of blood in the system)
• Total
peripheral resistance
, or the resistance of the
muscular arteries to the blood being pumped through.
The small arterioles are though to be the most
important factors in determini g peripheral resistance.
Because they have the smallest diameter, they are able
to almost stop blood flow into capillary beds when they
constrict, building up tremendous pressure in the arteries
behind t em a they prevent t e blood fro flowing
through. The arterioles are very responsive to stimula-
tion from the sympathetic nervous system; they constrict
when the sympathetic system is stimulated, increasing
total peripheral resistance and blood pressure. The body
us s th s responsiveness to regulate blood pressure on a
onstant basis, to ensure that there is enough pressure in
the system to deliver sufficient blood to the brain.
Baroreceptors
As the blood leaves the left ventricle through the aorta,
it influences specialised cells in the arch of the aorta
called
baroreceptors
(pressure receptors). Similar cells
are lo ated in the carotid arteries, which deliver blood
to the brain. If ther is sufficient pressure in these vessels,
the baroreceptors are stimulated, sending that informa-
tion t the brain. If the pressure falls, the stimulation of
the barorec ptors falls off. That information is also sent
to the brain.
The sensory input from the baroreceptors is received
in the medulla in an area called the
cardiovascular centre
or vasomotor centre. If the pressure is high, the medulla
stimul tes vasodilation and a decrease in cardiac rate and
ou put, causing the pressure in the system to drop. If the
p essure is low, the medulla directly stimulates an increase
i cardiac rate and output, and vasoconstriction; this
increases total peripheral resistance and raises the blood
pressure. The medulla mediates these effects through the
autonomic nervous system (see Chapter 29).
Th baroreceptor reflex functions continually to
maintain blood pressure within a predetermined range of
normal. For example, if you have been lying down flat
and suddenly stand up, the blood will rush to your feet
(an effect of gravity). You may even feel light-headed or
dizzy for a short time. When you stand and the blood flow
drops, the baroreceptors are not stretched. The medulla
senses this drop in stimulation of the baroreceptors and
stimulates a rise in heart rate and cardiac output, and
Thiazide and thiazide-like
diuretics
chlorthalidone
hydrochlorothiazide
indapamide
Potassium-sparing diuretics
amiloride
spiron lactone
triamterene
Beta-blockers
atenolol
betaxolol
metoprolol
nadolol
nebivolol
pindolol
propranolol
timolol
Alpha- a d beta-blockers
carvedilol
Alpha-adrenergic blockers
phenoxybenzamine
phentolamine
Alpha
1
-blockers
doxazosin
prazosin
terazosin
Alpha
2
-blockers
clonidine
methyldopa
moxonidine
midodrine
Sympathetic adrenergic
agonists or vasopressors
adrenaline
dobutamine
dopamine
ephedrine
isoprenaline
metaraminol
noradrenaline
phenylephrine
C H A P T E R 3 8
Agents to control blood glucose levels
579
of insulin delivery that are available or under study for
future use.
Hyperglycaemic crisis
Therapeutic actions and indications
Insulin is a hormone that promotes the storage of the
body’s fuels, facilitates the transport of various metabo-
lites and ions acr ss cell membranes and stimul tes the
synthesis of glycogen from glucose, of fats from lipids
and of proteins from amino acids. Insulin does these
things by reacting with specific receptor sites on the
cell. Figure 38.3 shows the sites of action of replacement
insulin and other drugs used to treat diabetic conditions.
See Table 38.2 for indications.
Pharmacokinetics
Various preparations of insulin are available to provide
short- and long-term coverage. These preparations are
processed within the body like endogenous insulin.
However, the peak, onset and duration of each vary
because of the placement or addition of glycine and/or
arginine chains. Maintenance doses are given by the
subcutaneous route only, and injection sites need to
be rotated regularly to avoid damage to muscles and
to pr vent subcutaneous atrophy. Regular insulin is
given intramuscularly or intravenously in emergency
situations.
Insulin is available in various preparations with a
wide range of peaks and durations of action. A person
may receive a combination of regular and isophane
insulin in the morning to cover the glucose peak from
breakfast (regular onset, 30 to 60 minutes) and the
lunch and dinner glucose peaks. The person may then
require another injection before bed. The types of
insulin used are determined by the anticipated eating
and exercise activities of any particular individual. It is
very important to make sure that one is using the correct
insulin preparation when administering the drug. Insulin
glargine (
Lantus
) and insulin detemir (
Levemir
) cannot
be mixed in solution with any other drug, including
other insulins.
Contraindications and cautions
Because insulin is used as a replacement hormone, there
are no contraindications. Care should be taken during
TABLE 38.2
DRUGS IN FOCUS Insulin
Drug name
Dosage/route
Usual indications
insuli (various typ s)
Varies based on response, diet, and activity
level
Treatment of type 1 diabetes mellitus;
treatment of type 2 diabetes mellitus
in people whose diabetes cannot be
controlled by diet or other agents;
treatment of severe ketoacidosis
or diabetic coma; treatment of
hyperkalaemia (in conjunction with
a glucose infusion to produce a shift
of potassium into the cells [polarising
solution]); also used for short courses
of therapy during periods of stress (e.g.
surgery, disease) in people with type 2
diabetes, for newly diagnosed people
being stabilised, for people with poor
control of glucose levels, and for people
with gestational diabetes
Safe medication administration
In 2009, l nte insulin was removed from the market as
name confusion had occurred between Lantus insulin and
lente insulin. The pharmacokinetics and dose of insulins vary
greatly. Use caution to make sure you know which insulin is
intended for the individual person. Lantus and Levemir insulin
cannot be mixed in a syringe with any other insulin or any
other drug. Use particular caution when working with these
two insulins.
The DHBNZ Safe and Quality Use of Medicines has
released an alert informing healthcare professionals to take
extra care when giving insulin Humalog preparation. There
are three Humalog preparations available in Australia and
New Zealand: Humalog, Humalog Mix25 and Humalog
Mix50. Potential harm can result if a person is given Humalog
rapid release as opposed to Humalog intermediate release.
The Australian Commission on Safety and Quality in
Health Care (ACSQHC) has developed 10 National Safety
and Quality Health Service Standards. These Standards
aim to improve the quality of health service provision
across Australia and provide a national statement of the
level of care consumers should be able to expect from
health services. Awareness and knowledge of Standard 4
on Medication Safety is an important part of the nurse’s
and midwife’s clinical repertoire. For more information, see
.
Text highlights
• In the
Care considerations
section of each
chap er, italics highlight the rationale for each
a e intervention, helping the student to apply the
information in a clinical situation. Elsewhere in
the text, the rationale is consistently provided for
therapeutic drug actions, co traindicati ns and
adverse effects.
C H A P T E R 2 6
Opioids, opioid antagonists and antimig aine agents
413
■■
Migraine headaches are severe, throbbing headaches
on one side of the head that may be associated with
an aura or warning syndrome. These headaches
are thought to be caused by arterial dilation and
hyperperfusion of the brain vessels.
KEY POINTS
Car considerations for
people receiving antimigraine agents
Assessment: History and examination
■
■
Assess for contraindications or cautions: any
known allergies to any components of the dr gs
to avoid hypersensitivity reactions
; history of MI,
CAD or hypertension,
which may be exacerbated
by the drug
; hepatic or renal dysfunction,
which
could alter the metabolism and excretion of the
drug
; pruritus or malnutrition,
which could be
exacerbated by ergot derivatives
; and current
status of pregnancy and breastfeeding,
which
would be cautions to the use of these drugs
.
■
■
Perform a physical assessment
to establish
baseline
status before beginning therapy, determine drug
effectiveness and evaluate for any potential
adverse effects.
■
■
Assess neurological status, including level of
orientation, affect and reflexes,
to evaluate CNS
effects of the drugs
.
■
■
Monitor for complaints of extremity numbness and
tingling
to identify effects on vascular constriction.
■
■
Inspect the skin for localised oedema, itching
or breakdown with ergot derivatives
to evaluate
potential dermatological effects.
■
■
Assess vital signs, including pulse rate and blood
pressure; obtain an ECG as appropriate
to evaluate
cardiac status for changes.
■
■
Provide thorough teaching, including drug name,
prescribed dose and schedule for administration;
measures to avoid adverse effects; warning
signs that may indicate possible problems; signs
of ergotism if taking ergot derivatives; safety
measures such as avoiding driving and avoiding
overdose; and importance of follow-up monitoring
nd evaluation
to enhance the person’s knowledge
about drug therapy and to promote compliance.
Evaluation
■
■
Monitor the person’s response to the drug (relief of
acu e migraine headaches).
■
■
Monitor for adverse effects (CV changes,
arrhythmias, hypertension, CNS changes).
■
■
Evaluate the effectiveness of the teaching plan
(person can give the drug name and dosage and
describe possible adverse effects to watch for,
specific measures to prevent them and warning
signs to report).
■
■
Monitor the effectiveness of comfort measures and
compliance with the regimen.
• In the
Drug list
at the beginning of each chapter,
a special icon appears next to the drug that is
considered the prototype drug of each class. In each
chapter, prototype summary boxes spotlight need-to-
know information for each prototype drug.
acting on the central and peripheral nervous systems
, is a sensory and emotional experi-
actual or potential tissue damage.
pain is part of the clinical pres-
isorders and is one of the hardest
the tissue damage has occurred. In some cases so-called
referred pain occurs. A person experiencing pain f om
damage to the heart muscle may actually feel the pain in
the neck or jaw. The sensation of pain is experienced in
hene
morphine
oxycodone
pethidine
remifentanil
tapentadol
tramadol
Opioid agonists–antagonists
buprenorphine
Opioid antagonists
aloxon
naltrexone
ANTIMIGRAINE AGENTS
Ergot derivatives
ergotamine
Triptans
eletriptan
naratriptan
sumatriptan
zolmitriptan
and peripheral nervous systems
drugs that bind
t activate them.
eceptors and are
ny opioids in the
include naloxon
ReVia
).
ptors and reverse
tory depression,
potension.
sal of the adverse
atory depression
id overdose. (See
ch opioid antag-
do ot have an
ividual who are
Contraindications and cautions
Opioid antagonists are contraindicated in the presence
of any know allergy to any opioid antagonist
to avoid
hypersensitivity react ons
. Caution should be used in
the following circumstances: duri g pregn ncy and
breastfeeding
because of potential adverse effects on
the f tus and neonate
; with opioid addiction
because
of the precipitation of a withdrawal syndrome
; and
with cardiovascular (CV) disease,
which could be
exacerbated by the reversal of the depressive effects of
opioids.
Adverse effects
The most frequently seen adverse effects associated with
these drugs relate to the blocking effects of the opioid
receptors. The most common effect is an acute opioid
abstinence syndrome that is characterised by nausea,
vomiting, sweating, tachycardia, hypertension, tremu-
lousness and feelings of anxiety. A naloxone challenge
should be administered before giving naltrexone to help
to avoid acute reactions.
CNS excitement and reversal of analgesia are espe-
cially c mmon after surgery. Cardiovascular (CV)
effects related to the reversal of the opioid depr ssion
can inclu e tac yc rdia, blood pressure changes, dys-
rhythmias and pul onary oedema.
Drug–d ug interacti ns
To reverse the effects of buprenorphine or dextropro-
poxyphene, larger doses of opioid antagonists may be
needed.
g drug name,
inistration;
fects; warning
lems; safety
etting
g making
rtant papers;
luation
to
ut drug
.
drug (relief of
anges, GI
rrhythmias,
hing plan
dosage and
atch for,
d warning
measures and
Prototype summary: Naloxone
Indications:
Complete or partial reversal of
opioid depression; diagnosis of suspected opioid
overdose.
Actions:
Pure opio d antagonist; re rses the effects
of the opioids, including respiratory depression,
sedation and hypotension.
Pharmacokinetics:
Route
Peak
Onset
Duration
•
Drugs in focus
tables clearly summarise and identify
the drugs within a class, highlighting them by generic
and trade names, usual dosage and indications. The
icon appears in these tables next to each drug that is
considered to be the prototype for its specific class.
ADULTS
Adults being treated for acute pain should be reassured
that the risk of add tion to an opioid during treatment
is remote.They should b encouraged to ask for pain
medication before the pain is acute, to get better
coverage for their pain. Many institutions allow people
to self-regulate intravenous drips to control their pain
postoperatively.
PREGNANCY AND BREASTFEEDING
The opioid ar contraindicated or should only be used
with caution during pregnancy because of the potential for
effects associated
nervous system,
effects.
Because older
impairment, they
levels of the drug
and excretion.Th
measures in effec
ambulate—when
hospital setting.
TABLE 26.1
DRUGS IN FOCUS Opioids
Drug ame
Dosage/route
Opioid agonists
alfentanil (Rapifen)
Spontaneous ventilation: 7 mcg/kg by slow IV
injection
Controlled ventilation: 20-50 mcg/kg by slow
IV injection
codeine (generic)
Adult: 15–60 mg PO, IM, IV or SC q 4–6 hours;
10–20 mg PO q 4–6 hours for cough
Paediatric: 0.5 mg/kg PO, IM or SC q
4–6 hours; 2.5–10 mg PO q 4–6 hours for
cough
dextropropoxyphene
(Doloxene)
100 mg PO q 4 hours as needed
fentanyl (Actiq, Duragesic,
Sublimaze)
Adult: 0.05–0.1 mg IM, 30–60 minutes
before surgery; 0.002 mg/kg IV or IM during
surgery; 0.05–0.1 mg postop ratively;
5 mcg/kg transmucosally; for transdermal
patch, calculate the previous day’s opioids
need and use table to convert to patch
strength; ionic delivery system, 40 mcg over
10 minutes
Paediatric (>2 years): 2–3 mcg/kg IM or IV;
base transmucosal dose on weight and do
not exceed 400 mcg
control is determined by the relative ability of each
drug to cause physical dependence. Opioid agonists
include alfentanil (
R pifen
), c dei e (ge eric), dextro-
propoxyphene (
Doloxe e
), fentanyl (
Actiq
,
Duragesic
,
Sublimaze
), hydromorphone (
Dilaudid
,
Jurnista
), meth-
adone (
Biodone
,
Physeptone
), morphine (
Anam rph
,
Sevredol
,
MS Contin
and others), oxyco one (
Endone
,
OxyContin
,
Oxynorm
,
Proladone
), pethidine (generic),
remifentanil (
Ultiva
), tapent d l (
Palexia SR
) (not avail-
able in New Zealand) and tramadol (
Durotram XR
,
Lodam
,
Tramal
and others).
Therapeutic actions and indications
The opioid agonists act at specific opioid receptor sites
in the CNS to produce analgesia, sedation and a sense of
well-being. Thes
sives and as adj
rapid analgesia,
Indications for
acute or chronic
during anaesthe
depending on th
usual indication
culation of a dos
In deciding
uation, it is imp
the person’s con
most effective in
effects. Each p
to a drug is als
morphine (Anamorph,
Kapanol, MS Contin)
Adult: 5–20 mg IM or SC or 15–30 mg PO q
4–6
rs
Paediatric: 0.1–0.2 g/kg IM or SC
oxycodone (OxyContin,
Oxynorm, Endone,
Proladone)
5–30 mg PO q 6 hours or 30 mg PR q
6–8 hours as needed
pethidine (generic)
Adult: 25–100 mg IM, SC or 25–50 mg slow IV
q 3–4 hours
Paediatric: 0.5–2 g/kg IM or SC q 3–4 hours
remifentanil (Ultiva)
Adult a chil ren >2 years: dos determined
by general anaesthetic being used
tapentadol (Pal xia SR)
Adult: 50 mg PO b.d.
tramadol (Durotram XR,
Lodam)
Adult: rapid relief of pain: 50-100 mg PO q
4–6 hours to a maximum 400 mg/day
Chronic pain: 25 mg/day PO titrated slowly to a
maximum 400 mg/day
Opioid agoni ts–antagonists
buprenorphine (Norspan,
Temgesic)
200–400 mcg SL q 6–8 hours, 300–600 mcg
M or IV q 6–8 hours or 1 transdermal patch
every 7 days
Opioid antagonists
nal xone (Narcan)
Adult: 0.4–2 mg IV, IM or SC q 2–3 minutes as
needed
Paediatric: 0.01 mg/kg IV, IM or SC
Neonatal: 0.01 mg/kg IV, IM or SC q
2–3 minutes or 0.06 mg/kg IM immed at birth
naltrexone (ReVia)
Adult: 50 mg/day PO
•
Focu on s fe medication admini tration
boxes
present important safety information to help keep the
person safe, prevent medication errors and increase
the therapeutic effectiveness f the drugs.
24
P A R T 1
Introduction to nursing pharmacol gy
dysfunction can lead to toxic lev ls of a drug in the bod
because he drug nnot be excreted. Figure 2.3 outlines
the pharmacokinetic proc ss that occur when a drug
is administe ed orally.
Pharmacology:
Excretion
Half-lif
The
half-life
of a
of drug in the b
it previously ac
20 mg of a dru
the drug will r
Two hours later,
level); in 2 more
information is i
ate timing for a
of a drug’s effec
calculations.)
The absorpt
the speed of bio
excreted are ll
mining the half
indicated in an
a healthy pers
estimate the half
or liver dysfunct
formation and
drug), allowing
dosing schedule.
The timing
achieve the mo
midwives can u
explain the imp
administration i
shows the effects
concentration of
Drug
swallowed
Drug dissolved in
gastrointestinal fluids
Dissolved drug
reaches intestine
Drug absorbed by
portal system
Drug in liver
Drug in
circulation
Drug distributed
throughout body
Drug
“does its thing”
Not dissolved, lost in faeces
Lost in acid
Lost in food, acid, digestion
Biotransformed to non-effective state
Bound to plasma proteins
Broken down in tissues
Bound to plasma proteins
Reaches reactive tissue
Excreted by kidneys, lungs, skin, etc.
Bound to f t tissue
Safe medication administration
The liver is very important in metabolising drugs in the
body and the kidneys are responsible for a large part of the
excretion of drugs from the body. One should get into the
habit of always checking a person’s live nd renal fu ction
before they start a drug r gimen. If the liver is not functioning
properly, the drug may no be metabolised correctly and
may reach toxic levels in the body. If the kidneys are not
functioning properly, the drug may not be excreted properly
and could accumulate in the body. Dose djustment ne ds to
be considered if a person has problems with either the liver
or the kidneys.
Determining
drug levels
A person is taki
You are trying to
drug will be gon
• In 12 hours, ha
body.
• In another 12 h
would remain i
• After 36 hours,
• After 48 hours,
remain.
• After 60 hours,
• After 72 hours,
• After 84 hours,
• Twelve more h
reduce the dru
• Finally, 12 mor
amount of the
would be quite
BOX 2.1
•
Focus on the evidence
boxes compile information
based on research to identif th best clinical practices
assoc ated with specific rug therapy.
94
P A R T 2
Chemotherapeutic agents
BACTERIA AND RESISTANCE TO
ANTIBIOTICS
Bacteria have survived for hundreds of years because
they can adapt to their environment. They do this by
altering their cell wall or enzyme systems to become
r sistant to (i.e. protect themselves from) unfavourable
conditions or situations. Many species of bacteria have
developed resistance to certain antibiotics. For example,
bacteria that were once very sensitive to penicillin have
devel ped an enzyme called penicillinase, which effec-
tively inactivates many of the penicillin-type drugs. New
drugs have had to be developed t effectively reat infec-
tions involving these once-controlled bacteria. It is very
important to use these drugs only when the identity and
se sitivity of he offending bacterium h ve been est b-
lished. Indiscriminate use of these new drugs can lead
to the dev lopment of more re istant strains for which
there is no effective antibiotic (see later discussion of
new antibiotics for additio al information on linezolid).
The longer an antibio ic has been i se, the great r
is the chance that the bacteria will develop into a resist-
ant strain. Efforts to control the mergence of r sistant
strains involve intensive educational programs that
advocate the use of antibiotics only when necessary and
effective and not for the treatment of viral infections
such as the common cold (Box 9.3).
In addition, the use of antibiotics may result in the
devel ment of superinfections or overgrowth of resistant
pathogens, such
antibiotics (parti
bacteria in the
opportunistic inv
are destroyed o
nothing to preve
In most cases th
effect (e.g. vagina
but in some case
t an the infectio
ment of the sup
and the potentia
cycle of treatmen
■■
The goal of an
population of
human immun
■■
Bacteria can b
f und in respir
(frequently fou
also be classifi
or aerobic (de
■■
Culture and se
antibiotic is ch
that may help
resistant-strai
KEY POINTS
Usi g antibiotics properly
In 2003, the US Food and Drug Administration (FDA) nd
Centers for Disease Control and Prevention (CDC) joined
efforts to educate the public and healthcare providers
about the dangers of inappropr ate use of antibiotics.
The evidence-based practice guidelines combine data
fro many studies to outline the most efficacious use
of antibiotics.To review some of the studies, review the
references listed in the Bibliography. Nurs s and mi wives
should include some of th following points about the
risks and dangers of antibiotic abuse in each person’s
education plan:
• Explain clearly that a particular antibiotic is effective
against only certain bacteria and that a culture needs to
be taken to identify the bacteria.
• Explain that bacteria can develop resistant strains that
will not be affected by antibiotics in the future, so use
of antibiotics now may make them less effective in
situations in which they are really necessary.
eople understand the importance of taking
the full course of medication as prescribed, even if they
feel better. Stopping an antibiotic midway through a
regimen ofte le
b cteria. Using
people saving u
infections or to s
• Tell people that
exposures to cer
to people that sa
they think they n
development of
tests that could i
• Offer other medi
decongestants,
request antibioti
something to ta
respond to antib
people who re
The publicity t
bacteria have rece
message across t
course of an antib
they are app opri
The e idence
BOX 9.3
•
Focus on herbal and alternative therapies
boxes
highlight known eract n with sp cific herbs or
alternative therapies that could affect the actions of
the drugs being discussed.
C H A P T E R
(MI). Table 31.
these agents.
Pharmacokinet
These drugs are
are distributed t
orally. Th y re
faeces and urine.
drug and prepar
Contraindicatio
The non-selecti
contraindicated
tivity to any co
serious hyperse
BOX 31.1
Drug therap across the lifespan
Adren rgic blocking agents
CHILDREN
Children are at greater risk for complications associated
with the use of adrenergic blocking agents, including
bradycardia, difficulty breathing and ch ges in gluco e
metabolism.The safety and efficacy for use of these
drugs has not been established for children younger than
18 years of age. If one f these drugs is used, the do e
for these agents needs to be calculated from the child’s
ody weight and age. It is good practice to have a second
person check t e dose calculation before administering
the drug to avoid potential toxic effects.Two adrenergic
blocking agents have es a li hed paediatric doses, and
the migh be he drugs to c nsider whe one is eeded:
praz s n is used to t eat hypert nsi n, and phentolamine,
which is used during surgery for phaeochromocytoma.
Children should be carefully monitored and supported
when these drugs are given.
ADULTS
Adults being treated with adrenergic blocking agents
should be cautioned about the many adverse effects
a sociated with the rugs. People with diabetes need
to be re-educated about ways to m nitor themselves
f r hyperglyca mia and hypoglycaemia because the
sympathetic reaction (sweating, feeling tense, increased
heart rate, rapid breathing) usually alerts people that
there is a problem with their glucose levels. People with
severe thyroid disease are also at high risk for serious
adverse effects when taking these drugs, and if one of
the is need d, the person sh uld be monitored very
closely. Propranolol and metoprolol are associated with
m re centr l nerv
other adrenergic
complications alr
while taking an a
a different agent.
PREGNANCY AN
In ge eral, there a
of adre ergic bloc
and th y shoul b
the benefit to the
fetu or ne nate.
and babies born t
adverse cardiovas
Many of these dru
Because of a simil
breastfeeding mot
baby if an adrener
OLDER ADULTS
Older people are
effects ass ciated
GI a d respirator
also have renal or
likely to have toxi
in metabolism an
be started on low
monitored very cl
or blood pressure
choice for older p
for hypertension
problems in the e
be used.
People who use alternative therapies as part of their
daily regimen should be cautio ed abou potential
increased adren rgic blocking effects if the f llowing
rapi s are combi ed with adrenergic
blocking agents:
• Ginseng, age—increased antihypertensive effects (risk
of hypotensio and increased CNS effects)
• Xuan shen, nightshade—slow heart rate (risk of severe
bradycardia and reflex arrhythmias)
• Celery, coriander, Di huang, fenugreek, goldenseal,
Java plum, xuan seng—lower blood glucose (increased
risk of severe hypoglycaemia)
• Saw palmetto—increased urinary tract complications
People who are pr cribe n adrenergic blocking
drug should be cautioned about the use of herbs, teas
and alternative medicines. If a person feels that one of
Herbal and alternative therapies
BOX 31.2
