McKenna's Pharmacology for Nursing, 2e

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P A R T 6  Drugs acting on the endocrine system

■■ Individuals receiving mineralocorticoids need to be evaluated for possible hypokalaemia and its associated cardiac effects and for fluid retention that could exacerbate heart failure and cause electrolyte abnormalities. CHAPTER SUMMARY ■■ The adrenal medulla is basically a sympathetic nerve ganglion that releases noradrenaline and adrenaline into the bloodstream in response to sympathetic stimulation. ■■ The adrenal cortex produces three types of corticosteroids: androgens (male and female sex hormones), glucocorticoids and mineralocorticoids. ■■ The corticosteroids are released normally in a diurnal rhythm, with the hypothalamus producing peak levels of corticotropin-releasing hormone (CRH) around midnight; peak adrenal response occurs around 9 a.m. The steroid levels drop slowly during the day to reach low levels in the evening, when the hypothalamus begins CRH secretion, with peak levels again occurring around midnight. Corticosteroids are also released as part of the sympathetic stress reaction to help the body conserve energy for the fight-or-flight response. ■■ Prolonged use of corticosteroids suppresses the normal hypothalamic–pituitary axis and leads to adrenal atrophy from lack of stimulation. Corticosteroids need to be tapered slowly after prolonged use to allow the adrenals to resume steroid production. ■■ The glucocorticoids increase glucose production, stimulate fat deposition and protein breakdown and inhibit protein formation. They are used clinically to block inflammation and the immune response and in conjunction with mineralocorticoids to treat adrenal insufficiency. ■■ The mineralocorticoids stimulate retention of sodium and water and excretion of potassium. They are used therapeutically in conjunction with glucocorticoids to treat adrenal insufficiency. ■■ Adverse effects of corticosteroids are related to exaggeration of the physiological effects; they include immunosuppression, peptic ulcer formation, fluid retention and oedema. ■■ Corticosteroids are used topically and locally to achieve the desired anti-inflammatory effects at a particular site without the systemic adverse effects that limit the usefulness of these drugs.

Care considerations for people receiving mineralocorticoids Assessment: History and examination ■ ■ Assess for allergy to these drugs to avoid

hypersensitivity reactions ; history of heart failure, hypertension or infections; high sodium intake; breastfeeding; and pregnancy, which could be cautions or contraindications to use of the drug . ■ ■ Assess blood pressure, pulse and adventitious breath sounds; weight and temperature; tissue turgor; reflexes and bilateral grip strength; and serum electrolyte levels, to determine baseline status before beginning therapy and for any potential adverse effects . Implementation with rationale ■ ■ Use only in conjunction with appropriate glucocorticoids to maintain control of electrolyte balance. ■ ■ Increase dose in times of stress to prevent adrenal insufficiency and to meet increased demands for corticosteroids under stress. ■ ■ Monitor for hypokalaemia (weakness, serum electrolytes) to detect the loss early and treat appropriately. ■ ■ Discontinue if signs of overdose (excessive weight gain, oedema, hypertension, cardiomegaly) occur to prevent the development of more severe toxicity. ■ ■ Provide thorough teaching, including drug name, dosage and administration; measures to avoid adverse effects; warning signs of problems; and the need for regular evaluation, including blood tests, to enhance knowledge about drug therapy and promote compliance. Evaluation ■ ■ Monitor response to the drug (maintenance of electrolyte balance). ■ ■ Monitor for adverse effects (fluid retention, oedema, hypokalaemia, headache). ■ ■ Evaluate the effectiveness of the teaching plan (person can name drug, dosage, adverse effects to watch for and specific measures to avoid them). ■ ■ Monitor effectiveness of comfort measures and compliance with the regimen.

KEY POINTS

■■ The mineralocorticoids stimulate retention of sodium and water and excretion of potassium. These drugs are used therapeutically in conjunction with glucocorticoids to treat adrenal insufficiency.

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