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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 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. Duration 24 hours Oral Varies 1–2 hours

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. 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. ■ ■ Perform a physical examination to establish ■ ■ 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. Implementation with rationale

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