McKenna's Pharmacology for Nursing, 2e

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P A R T 6  Drugs acting on the endocrine system

is also given by subcutaneous injection once daily and independent of meals. It has a duration of action of 24 hours. Sitagliptin is a DPP-4 inhibitor. It slows the break- down of GLP-1 in the body, prolonging the effects of increased insulin secretion, decreased glucagon secretion and slowed GI emptying. It is an oral drug, taken once a day, often in combination with other agents. It is rapidly absorbed, with peak effects in 1 to 4 hours. It has a half-life of 12.4 hours and is excreted unchanged in the urine. Few adverse effects have been reported with this drug, and it also must be used in combination with an appropriate diet and exercise program. Canagliflozin and dapagliflozin are among the newest oral hypoglycaemic agents on the market. These drugs lower glucose reabsorption by lowering the renal threshold for glucose. Hence, more glucose can be elim- inated in the urine. Both drugs are rapidly absorbed and extensively metabolised. Prototype summary: Metformin Indications: Adjunct to diet and exercise for the treatment of type 2 diabetics for people older than 10 years of age; extended release form for people older than 17 years of age; adjunct treatment with polycystic ovary syndrome. Actions: May increase the peripheral use of glucose, increase production of insulin, decrease hepatic glucose production and alter intestinal absorption of glucose. Pharmacokinetics: Route Onset Peak Duration Oral Slow 2–2.5 hours 10–16 hours T 1/2 : 6.2 and then 17 hours; metabolised in the liver and excreted in the urine. Adverse effects: Hypoglycaemia, lactic acidosis, GI upset, nausea, anorexia, diarrhoea, heartburn, allergic skin reaction. Care considerations for people taking other oral hypoglycaemic agents Assessment: History and examination ■ ■ Assess for contraindications or cautions: history of allergy to any of these agents to avoid hypersensitivity reactions ; severe renal or hepatic dysfunction, which could interfere with metabolism and excretion of the drugs ; and status of pregnancy or breastfeeding , which are contraindications to the use of these agents.

■ ■ Perform a complete physical assessment to establish baseline status before beginning therapy and to evaluate effectiveness and any potential adverse effects during therapy. ■ ■ Assess for the presence of any skin lesions for indication of possible infection and to establish appropriate sites for subcutaneous administration as appropriate ; orientation and reflexes; baseline pulse and blood pressure; adventitious breath sounds; abdominal sounds and function, to monitor effects of altered glucose levels. ■ ■ Assess body systems for changes suggesting possible complications associated with poor blood glucose control. ■ ■ Investigate nutritional intake, noting any problems with intake and adherence to prescribed diet. ■ ■ Assess activity level, including amount and degree of exercise. ■ ■ Monitor results of laboratory tests, including urinalysis, for evidence of glycosuria, and renal and liver function tests, especially with use of the thiazolidinediones, which can cause liver failure, to determine the need for possible dose adjustment and evaluate for signs of toxicity. ■ ■ Monitor blood glucose levels as ordered. ■ ■ Administer the drug as prescribed in the appropriate relationship to meals to ensure therapeutic effectiveness. ■ ■ Ensure that the individual is following diet and exercise modifications to improve effectiveness of the drug and decrease adverse effects. ■ ■ Monitor nutritional status to provide nutritional consultation as needed. ■ ■ Monitor response carefully; blood glucose monitoring is the most effective way to evaluate dose . Obtain blood glucose levels as ordered. ■ ■ Monitor liver enzymes of people receiving pioglitazone very carefully to avoid liver toxicity ; arrange to discontinue the drug to avert serious liver damage if liver toxicity develops. ■ ■ Monitor individuals during times of trauma, pregnancy or severe stress, and arrange to switch to insulin coverage as needed. ■ ■ Provide thorough teaching, including drug name, dosage and schedule for administration; administration technique if appropriate; need for food intake within specified time period; signs and symptoms of hypo- and hyperglycaemia; skin assessment, including daily inspection of feet; signs and symptoms to report immediately; measures to use when ill or unable to eat; proper diet and exercise program; hygiene measures; recommended Implementation with rationale