McKenna's Pharmacology for Nursing, 2e

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P A R T 2  Chemotherapeutic agents

after treatment has ended. Metronidazole and tinidazole combined with oral anticoagulants can lead to increased bleeding; people should be monitored closely and dose adjustments made to the anticoagulant during therapy and for up to 8 days after stopping therapy. Psychotic reactions have been reported when tinidazole or metro- nidazole is combined with disulfiram; this combination should be avoided, and 2 weeks should elapse between tinidazole therapy and the starting of disulfiram. Increased bone marrow suppression may occur if antifolate drugs (methotrexate, sulfonamides, etc.) are combined with pyrimethamine; discontinue pyrimeth- amine if signs of folate deficiency develop (diarrhoea, fatigue, weight loss, anaemia). ■ ■ Assess for contraindications and cautions: history of allergy to any of the antiprotozoals to prevent hypersensitivity reactions ; liver dysfunction that might interfere with metabolism and excretion of the drug or be exacerbated by the drug ; pregnancy, which is a contraindication , and breastfeeding because these drugs could enter the breast milk and be toxic to the infant ; CNS disease that could be exacerbated by the drug ; and candidiasis that could become severe as a result of the effects of these drugs on the normal flora . ■ ■ Perform a physical assessment to establish baseline data for determining the effectiveness of the drug and the occurrence of any adverse effects associated with drug therapy . ■ ■ Evaluate the CNS to check reflexes and muscle strength to identify the need for cautious drug use and to evaluate changes that occur as a result of drug therapy . ■ ■ Examine the skin and mucous membranes to check for lesions, colour, temperature and texture to monitor for adverse effects and superinfections . ■ ■ Evaluate liver function, including liver function tests, to determine the appropriateness of therapy and to monitor for toxicity . ■ ■ Obtain cultures to determine the exact protozoal species causing the disease . Implementation with rationale ■ ■ Arrange for appropriate culture and sensitivity tests before beginning therapy to ensure proper drug for susceptible organisms . Treatment may begin before test results are known. Care considerations for people receiving antiprotozoal agents Assessment: History and examination

■ ■ Administer a complete course of the drug to get the full beneficial effects . Use combination therapy as indicated. ■ ■ Monitor hepatic function before and periodically during treatment to arrange to effectively stop the drug if signs of failure or worsening liver function occur . ■ ■ Provide comfort and safety measures if CNS effects occur, such as side rails and assistance with ambulation if dizziness and weakness are present, to prevent injury to the person . ■ ■ Provide oral hygiene and ready access to bathroom facilities as needed to cope with GI effects . ■ ■ Arrange for the treatment of superinfections as appropriate to prevent severe infections . ■ ■ Provide small, frequent, nutritious meals if GI upset is severe to ensure proper nutrition . Monitor nutritional status and arrange a dietary consultation as needed. Taking the drug with food may also decrease GI upset. ■ ■ Instruct the person about the appropriate dosage regimen to enhance knowledge about drug therapy and to promote compliance . –– Take safety precautions, including changing position slowly and avoiding driving and hazardous tasks, if CNS effects occur. –– Take the drug with meals and try small, frequent meals if GI upset is a problem. –– Follow drug dosing guidelines carefully. –– Report severe GI problems and interference with nutrition; fever and chills, which may indicate the presence of a superinfection; and dizziness, unusual fatigue or weakness, which may indicate CNS effects. Evaluation ■ ■ Monitor response to the drug (resolution of infection and negative cultures for parasite). ■ ■ Monitor for adverse effects (orientation and affect, nutritional state, skin colour and lesions, hepatic function and occurrence of superinfections). ■ ■ Evaluate the effectiveness of the teaching plan (person can name the drug, dosage, possible adverse effects to watch for and specific measures to help avoid adverse effects). ■ ■ Monitor the effectiveness of comfort and safety measures and compliance with the regimen. See Critical thinking scenario for additional information related to coping with amoebiasis and the use of metronidazole. ■ ■ Provide the following teaching: