108
P A R T 2
Chemotherapeutic agents
KEY POINTS
■■
Fluoroquinolones inhibit the action of DNA enzymes
in susceptible gram-negative bacteria. They are used
to treat a wide range of infections.
■■
Monitor the person for headache, dizziness, GI upsets
and bone marrow depression, and caution the person
about the risk of photosensitivity reactions.
PENICILLINS AND PENICILLINASE-
RESISTANT ANTIBIOTICS
Penicillin (Table 9.5) was the first antibiotic introduced
for clinical use. Sir Alexander Fleming used
Penicillium
moulds to produce the original penicillin in the 1920s.
Subsequent versions of penicillin were developed to
decrease the adverse effects of the drug and to modify
it to act on resistant bacteria. Penicillins include ben-
zylpenicillin (
BenPen
), flucloxacillin (
Flopen
), procaine
penicillin (
Cilicaine
), dicloxacillin (
Diclocil
), amoxycil-
lin (
Amoxil
,
Augmentin
), ampicillin (
Amicyn
,
Ibimicyn
)
and ticarcillin (
Timentin
).
With the prolonged use of penicillin, more and more
bacterial species have synthesised the enzyme penicilli-
nase to counteract the effects of penicillin. Researchers
have developed a group of drugs with a resistance to
penicillinase, which allows them to remain effective
against bacteria that are now resistant to the penicillins.
The actual drug chosen depends on the sensitivity of the
bacteria causing the infection, the desired and available
routes and the personal experience of the clinician with
the particular agent.
Therapeutic actions and indications
The penicillins and penicillinase-resistant antibiot-
ics produce bactericidal effects by interfering with the
ability of susceptible bacteria to build their cell walls
when they are dividing (see Figure 9.2). These drugs
prevent the bacteria from biosynthesising the framework
KEY POINTS
■
■
Perform culture and sensitivity tests at the site of
infection.
■
■
Conduct assessment of orientation, affect and
reflexes
to establish a baseline for any CNS effects
of the drug.
■
■
Perform renal function tests, including BUN and
creatinine clearance,
to evaluate the status of renal
functioning and to assess necessary changes in
dose.
Implementation with rationale
■
■
Check culture and sensitivity reports
to ensure that
this is the drug of choice for this person.
■
■
Monitor renal function tests before initiating
therapy
to appropriately arrange for dose
reduction if necessary.
■
■
Ensure that the person receives the full course of
the fluoroquinolone as prescribed
to eradicate the
infection and to help prevent the emergence of
resistant strains.
■
■
Monitor the site of infection and presenting signs
and symptoms (e.g. fever, lethargy, urinary tract
signs and symptoms) throughout the course of
drug therapy.
Failure of these signs and symptoms
to resolve may indicate the need to reculture the
site.
Arrange to continue drug therapy for at least
2 days after resolution of all signs and symptoms
to help decrease the development of resistant
strains.
■
■
Provide small, frequent meals as tolerated, frequent
mouth care and ice chips or sugarless lollies to suck
if dry mouth is a problem
to relieve discomfort and
provide nutrition
, and provide
adequate fluids to
replace those lost with diarrhoea.
■
■
Implement safety measures, including adequate
lighting, use of side rails and assistance with
ambulation
to protect the person from injury if
CNS effects occur.
■
■
Instruct the person about the appropriate dosage
schedule and possible adverse effects
to enhance
knowledge about drug therapy and to promote
compliance.
■
■
Provide the following teaching:
–– Take safety precautions, including changing
position slowly and avoiding driving and
hazardous tasks, if CNS effects occur.
–– Try to drink a lot of fluids and to maintain
nutrition (very important), although nausea,
vomiting and diarrhoea may occur.
–– Avoid ultraviolet light and sun exposure, using
protective clothing and sunscreens.
–– Report difficulty breathing, severe headache,
severe diarrhoea, severe skin rash, fainting spells
and heart palpitations.
Evaluation
■
■
Monitor person’s response to the drug (resolution
of bacterial infection).
■
■
Monitor for adverse effects (orientation and affect,
GI effects, photosensitivity).
■
■
Evaluate effectiveness of the teaching plan (person
can name drug, dosage, possible adverse effects to
expect and specific measures to help avoid adverse
effects).
■
■
Monitor effectiveness of comfort and safety
measures and compliance with the therapeutic
regimen.
