McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 9  Antibiotics

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. ■ ■ 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. ■ ■ 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. ■ ■ 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. Care considerations for people receiving sulfonamides Assessment: History and examination

■ ■ 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. ■ ■ 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. ■ ■ 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. Implementation with rationale