C H A P T E R 9
Antibiotics
113
Adverse effects
Adverse effects associated with sulfonamides include
GI effects such as nausea, vomiting, diarrhoea, abdomi-
nal pain, anorexia, stomatitis and hepatic injury, which
are all related to direct irritation of the GI tract and the
death of normal bacteria. Renal effects are related to the
filtration of the drug in the glomerulus and include cryst-
alluria, haematuria and proteinuria, which can progress
to a nephritic syndrome and possible toxic nephrosis.
CNS effects include headache, dizziness, vertigo, ataxia,
convulsions and depression (possibly related to drug
effects on the nerves). Bone marrow depression may
occur and is related to drug effects on the cells that turn
over rapidly in the bone marrow.
Dermatological effects include photosensitivity and
rash related to direct effects on the dermal cells. A wide
range of hypersensitivity reactions may also occur.
Clinically important drug–drug interactions
If sulfonamides are taken with glipizide, glibenclamide
or glicazide, the risk of hypoglycaemia increases. If this
combination is needed, the person should be monitored
and a dose adjustment of the antidiabetic agent should
be made. An increase in dose will then be needed when
sulfonamide therapy stops.
When sulfonamides are taken with cyclosporin, the
risk of nephrotoxicity rises. If this combination is essen-
tial, the person should be monitored closely and the
sulfonamide stopped at any sign of renal dysfunction.
Care considerations for
people receiving sulfonamides
Assessment: History and examination
■
■
Assess for
possible contraindications or cautions
:
known allergy to any sulfonamide, sulfonylureas
or thiazide diuretic
because cross-sensitivity often
results
(obtain specific information about the
nature and occurrence of allergic reactions); history
of renal disease
that could interfere with excretion
of the drug and lead to increased toxicity
; and
current pregnancy or breastfeeding status.
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■
Perform a physical assessment
to establish baseline
data for assessing the effectiveness of the drug and
the occurrence of any adverse effects associated
with drug therapy.
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■
Examine skin and mucous membranes for any rash
or lesions
to provide a baseline for possible adverse
effects.
■
■
Obtain specimens for culture and sensitivity tests
at the site of infection
to ensure that this is the
appropriate drug for this person.
■
■
Note respiratory status
to provide a baseline for
the occurrence of hypersensitivity reactions.
■
■
Conduct assessment of orientation, affect and
reflexes
to monitor for adverse drug effects
and
examination of the abdomen
to monitor for
adverse effects.
■
■
Monitor renal function test findings, including
BUN and creatinine clearance,
to evaluate the
status of renal functioning and to determine
any needed alteration in dosage.
Also perform a
full blood count (FBC)
to establish a baseline to
monitor for adverse effects.
Implementation with rationale
■
■
Check culture and sensitivity reports
to ensure that
this is the drug of choice for this person and repeat
cultures if response is not as anticipated.
■
■
Monitor renal function tests before and
periodically during therapy
to arrange for a dose
reduction as necessary.
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■
Ensure that the person receives the full course
of the sulfonamide as prescribed
to increase
therapeutic effects and decrease the risk for
development of resistant strains.
■
■
Administer oral drug on an empty stomach 1 hour
before or 2 hours after meals with a full glass
of water
to promote adequate absorption of the
drug.
■
■
Discontinue immediately if hypersensitivity
reactions occur
to prevent potentially fatal
reactions.
■
■
Provide small, frequent meals and adequate fluids
as tolerated, encourage frequent mouth care,
and offer ice chips or sugarless lollies to suck if
stomatitis and sore mouth are problems
to relieve
discomfort, ensure nutrition and replace fluid lost
with diarrhoea.
■
■
Monitor FBC and urinalysis test results before and
periodically during therapy
to check for adverse
effects.
■
■
Instruct the person about the appropriate dosage
regimen, the proper way to take the drug (on an
empty stomach with a full glass of water) and
possible adverse effects,
to enhance knowledge
about drug therapy and to promote compliance.
■
■
Provide the following teaching:
–– Avoid driving or operating dangerous machinery
because dizziness, lethargy and ataxia may
occur.
–– Try to drink a lot of fluids and maintain nutrition
(very important), even though nausea, vomiting
and diarrhoea may occur.
–– Report difficulty in breathing, rash, ringing in the
ears, fever, sore throat or blood in the urine.
