McKenna's Pharmacology for Nursing, 2e

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P A R T 2  Chemotherapeutic agents

Care considerations for people receiving antimetabolites Assessment: History and examination ■ ■ Assess for contraindications and cautions:

■■ Antimetabolites inhibit DNA production by inhibiting metabolites needed for the synthesis of DNA in susceptible cells. ■■ Antimetabolites are S phase cell cycle–specific and are used for some leukaemias, as well as some GI and basal cell cancers. ■■ Bone marrow suppression, alopecia and toxic GI effects are common adverse effects of antimetabolites. ■ ■ Protect the individual from exposure to infections because bone marrow suppression will limit immune/inflammatory responses . ■ ■ Provide support and encouragement to help the person cope with the diagnosis and the effects of drug therapy. ■ ■ Provide the following teaching: –– Follow the appropriate dosage regimen, including dates to return for further doses. People need to be reminded to report all other drugs and alternative therapies that they might be using. Box 14.7 discusses alternative therapies often used by cancer sufferers that could interact with their drug regimen. –– Maintain nutrition if GI effects are severe. –– Cover the head at extremes of temperature if alopecia is anticipated. –– Plan for appropriate rest periods because fatigue and weakness are common effects of the drugs. –– Avoid situations that might lead to infection, including crowded places, sick people and working in the soil. –– Use safety measures such as not driving or using dangerous equipment, due to possible dizziness, headache and drowsiness. –– Think about consulting with a healthcare provider, if appropriate, due to the possibility of impaired fertility. –– Use barrier contraceptives to reduce the risk of pregnancy during therapy. Evaluation ■ ■ Monitor response to the drug (alleviation of cancer being treated, palliation of signs and symptoms of cancer, palliation of rheumatoid arthritis or psoriasis). ■ ■ Monitor for adverse effects (bone marrow suppression, GI toxicity, neurotoxicity, alopecia, renal or hepatic dysfunction). ■ ■ 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.

history of allergy to the specific antimetabolite to avoid hypersensitivity reactions ; bone marrow suppression to prevent further suppression ; renal or hepatic dysfunction that might interfere with drug metabolism and excretion ; current status related to pregnancy or breastfeeding to prevent potentially serious effects to the fetus or breastfeeding baby ; and a history of GI ulcerative disease, which could be exacerbated with the use of these drugs . ■ ■ 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 . ■ ■ Assess orientation and reflexes to evaluate any CNS effects ; respiratory rate and adventitious sounds to monitor the disease and to evaluate for respiratory or hypersensitivity effects ; pulse, rhythm and cardiac auscultation to monitor for systemic or cardiovascular effects ; and bowel sounds and mucous membrane status to monitor for GI effects . ■ ■ Monitor the results of laboratory tests such as FBC with differential to identify possible bone marrow suppression and toxic drug effects; and renal and liver function tests to determine the need for possible dose adjustment and toxic drug effects . Implementation with rationale ■ ■ Arrange for blood tests to monitor bone marrow function before, periodically during, and for at least 3 weeks after therapy to arrange to discontinue the drug or reduce the dose as needed . ■ ■ Administer medication according to the scheduled protocol and in combination with other drugs as indicated to improve the effectiveness of drug therapy . ■ ■ Ensure the person is well hydrated to decrease the risk of renal toxicity . ■ ■ Provide small, frequent meals, frequent mouth care and dietary consultation as appropriate to maintain nutrition when GI effects are severe . Anticipate the use of antiemetics as necessary. (See Box 14.5.) ■ ■ Arrange for proper head covering at extremes of temperature if alopecia occurs; a wig, scarf or hat is important for maintaining body temperature . If alopecia is an anticipated effect of drug therapy, advise the person to obtain a wig or head covering before the condition occurs to promote self-esteem and a positive body image .

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