McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 3 5 Hypothalamic and pituitary agents

Drug therapy across the lifespan

BOX 35.1

Hypothalamic and pituitary agents CHILDREN

( Eligard , Lucrin ) (blocks GnRH effects) and nafare­ lin ( Synarel ) (blocks GnRH) (not available in New Zealand). See Table 35.1 for a complete list of these drugs. Therapeutic actions and indications The hypothalamic hormones are found in such minute quantities that the actual chemical structures of all of OLDER ADULTS Older adults may be more susceptible to the imbalances associated with alterations in the endocrine system.They should be evaluated periodically during treatment for hydration and nutrition, as well as for electrolyte balance. Proper administration technique should be reviewed and nasal mucous membranes should be evaluated regularly because older people are more apt to develop dehydrated membranes and possibly ulcerations, leading to improper dosing of drugs delivered nasally. and lack of therapeutic effect. Adults receiving regular injections of these drugs should learn the proper storage, preparation and administration of the drug, including rotation of injection sites. PREGNANCY AND BREASTFEEDING These drugs should not be used during pregnancy or breastfeeding unless the benefit to the mother clearly outweighs any risk to the fetus or neonate because of the potential for severe adverse effects associated with the use of these drugs.

Not all of these hormones are available for pharmaco­ logical use (see Table 34.1 in Chapter 34). Available hypothalamic releasing hormones include corticotropin-releasing hormone (CRH) (generic), and goserelin ( Zoladex ) (synthetic GnRH). Available antag­ onists that block the effects of hypothalamic releasing hormones include cetrorelix ( Cetrotide ) (blocks GnRH), ganirelix ( Orgalutran ) (blocks GnRH), leuprorelin Adults also need frequent monitoring of electrolytes and blood sugar levels when receiving any of these agents. Adults using nasal forms of drugs to control diabetes insipidus should review the proper administration of the drug with the primary care provider periodically; inappropriate administration can lead to complications Children who receive any of the hypothalamic or pituitary agents need to be monitored closely for adverse effects associated with changes in overall endocrine function, particularly growth, development and metabolism. Periodic radiograph of the long bones, as well as monitoring of blood sugar levels and electrolytes, should be a standard part of the treatment plan. Children receiving growth hormone pose many challenges (see Box 35.2). Children who are using desmopressin for diabetes insipidus need to have the administration technique monitored and should have an adult responsible for the overall treatment protocol. ADULTS

TABLE 35.1

DRUGS IN FOCUS Drugs affecting hypothalamic hormones

Drug name

Dosage/route

Usual indications

Agonists corticotrophin-releasing hormone (CRH) (generic)

10–25 units in 500 mL 5% dextrose in water, infused over 8 hours

Diagnosis of Cushing’s disease; being studied for treatment of peritumoral brain oedema Used as an antineoplastic agent for treatment of specific hormone-stimulated cancers

goserelin (Zoladex)

Implant inserted SC into anterior abdominal wall every three months

Antagonists cetrorelix (Cetrotide)

250 mcg/d SC lower abdominal wall, commencing day five to six followed by 3 mg on day seven of ovarian stimulation

Prevention of ovulation in women undergoing assisted reproductive techniques

ganirelix (Orgalutran)

250 mcg SC on day two or three of the menstrual cycle

Inhibition of premature luteinising hormone surge in women undergoing controlled ovarian stimulation as part of a fertility program Used as antineoplastic agent for treatment of specific cancers; treatment of endometriosis

Prostate cancer: 1 mg/day SC or various depot preparations: 3.75 mg IM endometriosis— once a month 400 mcg/day divided as one spray in left nostril a.m. or p.m.; one spray in right nostril a.m. or p.m.

leuprorelin (Eligard, Lucrin)

nafarelin (Synarel)

Treatment of endometriosis