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P A R T 2
Chemotherapeutic agents
causing nausea, vomiting, anorexia, stomach upset
and abdominal pain. Rifampicin and rifabutin cause
discolouration of body fluids from urine to sweat and
tears. Alert people that in many instances orange-tinged
urine, sweat and tears may stain clothing and perma-
nently stain contact lenses. This can be frightening if
the person is not alerted to the possibility that it will
happen. As with other antibiotics, there is always a pos-
sibility of hypersensitivity reactions. Monitor the person
on a regular basis.
Clinically important drug–drug interactions
When rifampicin and isoniazid are used in combination,
the possibility of toxic liver reactions increases. People
should be monitored closely.
Increased metabolism and decreased drug effective-
ness occur as a result of administration of quinidine,
metoprolol, propranolol, corticosteroids, oral contra-
ceptives, oral anticoagulants, oral antidiabetic agents,
digoxin, theophylline, methadone, phenytoin, verapa-
mil, cyclosporin or ketoconazole in combination with
rifampicin or rifabutin. People who are taking these
drug combinations should be monitored closely and
dose adjustments made as needed.
Prototype summary: Isoniazid
Indications:
Treatment of tuberculosis as part of
combination therapy; prophylactic treatment
of household members of recently diagnosed
tuberculars.
Actions:
Interferes with lipid and nucleic acid
synthesis in actively growing tubercle bacilli.
Pharmacokinetics:
Route Onset
Peak
Duration
Oral
Varies
1–2 hours
24 hours
T
1/2
:
1 to 4 hours; metabolised in the liver, excreted
in the urine.
Adverse effects:
Peripheral neuropathies, nausea,
vomiting, hepatitis, bone marrow suppression,
fever, local irritation at injection sites,
gynaecomastia, lupus syndrome.
Care considerations for
people receiving antimycobacterials
Assessment: History and examination
■
■
Assess for
possible contraindications or cautions
:
known allergy to any antimycobacterial drug
(obtain specific information about the nature and
occurrence of allergic reactions); history of renal
or hepatic disease,
which could interfere with
metabolism and excretion of the drug and lead to
toxicity
; history of CNS dysfunction, including
seizure disorders and neuritis,
which could be
exacerbated by adverse drug effects
; and current
pregnancy status
to ensure appropriate drug
selection to prevent adverse effects on the fetus.
■
■
Perform a physical examination
to establish
baseline data for assessing the effectiveness of the
drug and the occurrence of any adverse effects
associated with drug therapy.
■
■
Examine the skin for any rash or lesions
to provide
a baseline for possible adverse effects
.
■
■
Obtain specimens for culture and sensitivity testing
to establish the sensitivity of the organism being
treated.
■
■
Evaluate CNS for orientation, affect and reflexes
to establish a baseline and to monitor for adverse
effects.
■
■
Note respiratory status
to provide a baseline for
the occurrence of hypersensitivity reactions.
■
■
Evaluate renal and liver function tests, including
BUN and creatinine clearance,
to assess the status
of renal and liver functioning so as to determine
any needed alteration in dose.
Implementation with rationale
■
■
Check culture and sensitivity reports
to ensure
that this is the drug of choice for this person, and
arrange repeated cultures if response is not as
anticipated.
■
■
Monitor renal and liver function test results before
and periodically during therapy
to arrange for dose
reduction as needed.
■
■
Ensure that the person receives the full course of
the drugs
to improve effectiveness and decrease
the risk of development of resistant bacterial
strains.
These drugs are taken for years and often
in combination. Periodic medical evaluation
and reteaching are often essential to ensure
compliance.
■
■
Discontinue drug immediately if hypersensitivity
reactions occur
to avert potentially serious
reactions.
■
■
Encourage the person to eat small, frequent meals
as tolerated, perform frequent mouth care and
drink adequate fluids
to ensure adequate nutrition
and hydration.
Monitor nutrition if GI effects
become a problem.
■
■
Instruct the person about the appropriate dosage
regimen, use of drug combinations and possible
adverse effects
to enhance knowledge about drug
therapy and to promote compliance.
