McKenna's Pharmacology for Nursing, 2e

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P A R T 6  Drugs acting on the endocrine system

Drug therapy across the lifespan

BOX 36.2

Corticosteroids CHILDREN

Systemic use is indicated for the treatment of some cancers, hypocalcaemia associated with cancer, haema- tological disorders and some neurological infections. When combined with mineralocorticoids, some of these drugs can be used in replacement therapy for adrenal insufficiency. See Table 36.3 for information on each type of glucocorticoid agent. Pharmacokinetics These drugs are absorbed well from many sites. They are metabolised by natural systems, mostly within the liver, and are excreted in the urine. The glucocorticoids are known to cross the placenta and to enter breast milk; they should be used during pregnancy and breastfeeding only if the benefits to the mother clearly outweigh the potential risks to the fetus or neonate. Beclomethasone is available in the form of a respira- tory inhalant and nasal spray. Betamethasone is a long-acting steroid available for systemic, parenteral use in acute situations, as well as orally and as a topical application. Older adults are more likely to have hepatic and/or renal impairment, which could lead to accumulation of the drug and resultant toxic effects.They are also more likely to have medical conditions that could be imbalanced by changes in fluid and electrolytes, metabolism changes, and other drug effects. Such conditions include diabetes, heart failure, osteoporosis, coronary artery disease and immune suppression. Careful monitoring of drug dose and response to the drug should be done on a regular basis. combining these preparations with prescription topical corticosteroids.They also should be cautioned to apply any of these sparingly and to avoid applying them to open lesions or excoriated areas. With long-term therapy, the importance of avoiding exposure to infection—crowded areas, people with colds or the flu, activities associated with injury—should be stressed. If an injury or infection should occur, the person should be encouraged to seek medical care. Monitoring blood glucose levels should be done regularly. PREGNANCY AND BREASTFEEDING These drugs should not be used during pregnancy because they cross the placenta and could cause adverse effects on the fetus. If the benefit to the mother clearly outweighs the potential risk to the fetus, they should be used with caution. Breastfeeding women should find another method of feeding the baby if corticosteroids are needed because of the potential for serious adverse effects on the baby. OLDER ADULTS Older adults are more likely to experience the adverse effects associated with these drugs, and the dose should be reduced and the person monitored very closely.

Therapeutic actions and indications Glucocorticoids enter target cells and bind to cytoplas- mic receptors, initiating many complex reactions that are responsible for anti-inflammatory and immunosuppres- sive effects. Hydrocortisone, cortisone and prednisone also have some mineralocorticoid activity and affect potassium, sodium and water levels in the body. Glucocorticoids are indicated for the short-term treatment of many inflammatory disorders, to relieve discomfort and to give the body a chance to heal from the effects of inflammation. They block the actions of arachidonic acid, which leads to a decrease in the for- mation of prostaglandins and leukotrienes. Without these chemicals, the normal inflammatory reaction is blocked. They also impair the ability of phagocytes to leave the bloodstream and move to injured tissues, and they inhibit the ability of lymphocytes to act within the immune system, including a blocking of the pro- duction of antibodies. They can be used to treat local inflammation as topical agents, intranasal or inhaled agents, intra-articular injections and ophthalmic agents. Corticosteroids are used in children for the same indications as in adults.The dose for children is determined by the severity of the condition being treated and the response to the drug, not on a weight or age formula. Children need to be monitored closely for any effects on growth and development, and dose adjustments should be made or drug discontinued if growth is severely retarded. Topical use of corticosteroids should be limited in children; because their body surface area is comparatively large, the amount of the drug absorbed in relation to weight is greater than in an adult. Apply sparingly and do not use in the presence of open lesions. Do not occlude treated areas with dressings or nappies, which may increase the risk of systemic absorption. Children need to be supervised when using nasal sprays or respiratory inhalants to ensure that proper technique is being used. Children receiving long-term therapy should be protected from exposure to infection, and special precautions should be instituted to avoid injury. If injuries or infections do occur, the child should be seen by a primary care provider as soon as possible. ADULTS Adults should be reminded of the importance of taking these drugs in the morning to approximate diurnal rhythm. They should also be cautioned about the importance of tapering the drug rather than stopping abruptly. Several over-the-counter topical preparations contain corticosteroids, and adults should be cautioned to avoid