Learning Outcomes
By the end of this section, you should be able to:
- 26.2.1 Identify the characteristics of growth hormone drugs used to treat pituitary disorders.
- 26.2.2 Explain the indications, actions, adverse reactions, contraindications, and interactions of growth hormone drugs used to treat pituitary disorders.
- 26.2.3 Describe nursing implications of growth hormone drugs used to treat pituitary disorders.
- 26.2.4 Explain the client education related to growth hormone drugs used to treat pituitary disorders.
Growth Hormone
Growth hormones and suppressants are used to treat various growth and development disorders. Growth hormone, also known as somatotropin or human growth hormone, is essential for the body’s growth and development. Growth hormone stimulates the production of the insulin-like growth factor-1 (IGF-1) in the liver, which promotes the growth of bone, muscle, and other tissues. Growth hormone also helps to regulate metabolism and break down fats. Growth hormone is particularly important during childhood and adolescence when it promotes the growth and development of the body. However, growth hormone continues to be important throughout adulthood, helping to maintain healthy bone density, muscle mass, and overall well-being.
Deficiencies in growth hormone can lead to stunted growth, delayed puberty, and other health issues. Conversely, excessive growth hormone production can result in abnormal growth of bones and soft tissues, causing gigantism in children or acromegaly in adults.
Somatropin
Somatropin (different from somatotropin mentioned above) is a recombinant growth hormone that is used to treat failure to grow due to growth hormone deficiency in pediatric and adult clients; some forms of this prescription are indicated in the treatment of Prader-Willi syndrome. The drug is available in a subcutaneous injection dosage form and is individualized based on the client needs.
Drug interactions include glucocorticoids, which may oppose the growth-promoting effects of somatropin; oral estrogen, which impacts growth hormone secretion; and insulin or oral diabetes drugs, which may need dosages altered due to somatropin increasing glucose levels in the blood. The most common adverse effects are injection site reaction, rash, lipoatrophy, thyroid hormone suppression, and headaches. Somatropin is contraindicated in clients who are critically ill or have active malignancy, impaired glucose tolerance or diabetes, hypersensitivity, or closed epiphyses.
Growth Hormone Suppressants
Growth hormone suppressants are medications used to reduce the production or activity of growth hormone in the body. These drugs are typically used to treat medical conditions such as acromegaly or gigantism. Suppressants include somatostatin analogs, dopamine agonists, and growth hormone receptor antagonists. Nurses should note that these drugs should only be used under the guidance of a qualified health care provider because they can have significant side effects on the body and may interact with other medications or medical conditions.
Bromocriptine Mesylate
Bromocriptine mesylate is a dopamine receptor agonist. This grown hormone suppressant stimulates the dopamine receptors in the brain and helps to reduce prolactin production as well as lessen symptoms of Parkinson’s disease. It also is used to treat clients with acromegaly or those with high levels of prolactin, which can cause a lack of menstrual periods and infertility. Bromocriptine mesylate is readily absorbed by the gastrointestinal tract and mainly excreted in the urine. Adverse effects include nausea, headache, dizziness, fatigue, vomiting, abdominal cramps, nasal congestion, constipation, and drowsiness. This drug is contraindicated in clients with uncontrolled hypertension, hypersensitivity, and pregnancy.
Lanreotide Acetate
The growth hormone suppressant lanreotide acetate is a somatostatin analog and is used to treat acromegaly in clients who have had an inadequate response to or cannot be treated with surgery and/or radiotherapy and to treat clients with certain types of unresectable tumors. Drug interactions include cyclosporine, bromocriptine, and beta blockers. Adverse reactions include diarrhea, cholelithiasis, abdominal pain, nausea, and injection site reactions. Lanreotide acetate is contraindicated in clients with previous hypersensitivity reaction to lanreotide or any of the ingredients in the formulation.
Octreotide Acetate
Octreotide acetate inhibits growth hormone as a suppressant and is used in the treatment of acromegaly and certain types of tumors. See Table 26.3 for additional information on octreotide acetate.
Pegvisomant
The growth hormone receptor antagonist pegvisomant is indicated for the treatment of acromegaly in clients who have inadequate response to surgery or radiation therapy or for whom these therapies are inappropriate. Adverse reactions include infection, pain, nausea, diarrhea, abnormal liver tests, flu-like symptoms, and injection site reactions. Pegvisomant is contraindicated in clients with diabetes or hypoglycemia, liver toxicity, or hypersensitivity.
Table 26.2 lists common growth hormone suppressants and typical routes and dosing for adult and pediatric clients.
| Drug | Routes and Dosage Ranges |
|---|---|
| Bromocriptine mesylate (Parlodel) |
Acromegaly: Adults: 1.25–2.5 mg orally once daily. May increase by 1.25–2.5 mg every 2–7 days until optimal therapeutic response is achieved. Typical maintenance dose: 20–30 mg/day, in divided doses. Maximum dose: 100 mg/day. Children: Not Food and Drug Administration (FDA) approved for children. Prolactin-secreting pituitary adenoma: Adults: 1.25–2.5 mg orally once daily. May increase every 2–7 days until optimal therapeutic response is achieved. Typical maintenance dose: 2.5–15 mg/day. Children 11–15 years of age: Initial dose: One-half to one 2–5 mg scored tablet orally once daily. Dosing may need to be increased as tolerated until a therapeutic response is achieved. Therapeutic dosage: 2.5–10 mg daily. |
| Lanreotide acetate (Somatuline) | Acromegaly: Adults: 90 mg subcutaneously every 4 weeks for 3 months; thereafter, dosing is based on growth hormone levels. Children: Safety not established in children. |
| Octreotide acetate (Sandostatin) | Acromegaly: Adults: Initial dose: 50 mcg subcutaneously, 2–3 times daily; no added benefit from doses beyond 300 mcg/day. Other routes of administration include intramuscular (depot) and oral. Children: Safety not established in children. |
| Pegvisomant (Somavert) | Acromegaly: Adults: Loading dose: 40 mg subcutaneously; on the following day, begin 10 mg subcutaneously daily. Adjust in 5 mg increments every 4–6 weeks based on serum IGF-1 concentrations. Recommended dosage: 10–30 mg/day subcutaneously; maximum dose: 30 mg/day. Children: Safety not established in children. |
Adverse Effects and Contraindications
Common adverse effects of growth hormone suppressants include gastrointestinal symptoms such as abdominal pain, diarrhea, nausea, and vomiting; low or high blood glucose levels; vitamin B12 deficiency; fatigue and weakness; and injection site reactions such as redness, swelling, and pain at the injection site.
Contraindications include hypersensitivity to the drugs or any of their components, uncontrolled diabetes—as growth hormone suppressants can have potential effects on blood glucose regulation—severe liver disease, and severe kidney disease. These drugs are metabolized by the liver and can cause further hepatic impairment in clients with liver disease, and because they are excreted in the urine, they can cause further renal insufficiency in clients with kidney disease.
Table 26.3 is a drug prototype table for growth hormone suppressants featuring octreotide acetate. It lists drug class, mechanism of action, adult dosage, indications, therapeutic effects, drug and food interactions, adverse effects, and contraindications.
| Drug Class Growth hormone suppressant Mechanism of Action Exerts pharmacologic actions similar to the natural hormone somatostatin and inhibits growth hormone, glucagon, and insulin |
Drug Dosage Adults: Initial dose: 50 mcg subcutaneously, 2–3 times daily; no added benefit from doses beyond 300 mcg/day. Other routes of administration include intramuscular (depot) and oral. Children: Safety not established in children. |
| Indications Acromegaly Carcinoid tumors Vasoactive intestinal peptide tumors Therapeutic Effects Reduces growth hormone Reduces tumor size or and improves symptoms of carcinoid tumors |
Drug Interactions Beta blockers Insulin Oral diabetes drugs Food Interactions No significant interactions |
| Adverse Effects Gall bladder abnormalities Bradycardia and arrhythmias Diarrhea/nausea/abdominal discomfort Hypo/hyperglycemia Hypothyroidism |
Contraindications Hypersensitivity Atrioventricular block Caution: Monitor closely in clients who have cholelithiasis or complications of cholelithiasis |
Nursing Implications
The nurse should do the following for clients who are taking growth hormone suppressants:
- Assess the client’s medical history, current drug list, and allergies.
- Assess the client’s baseline height, weight, and vital signs.
- Ensure the drug is prepared appropriately using aseptic technique and verify dosage before administration.
- Monitor the client’s response to the drug, including any changes in height, weight, and vital signs.
- Monitor closely for injection site reactions and other adverse reactions such as pain, nausea, and diarrhea.
- Monitor IGF-1 levels and liver function, and report abnormalities to the health care provider.
- Monitor for thyroid suppression and elevated glucose levels and notify the health care provider of abnormalities.
- Provide client teaching regarding the drug and when to call the health care provider. See below for additional client teaching guidelines.
Client Teaching Guidelines
The client taking a growth hormone suppressant should:
- Keep this drug in its original carton to protect it from light.
- If injectable:
- Choose injection site (thigh, abdomen, or buttock) as recommended by their health care provider, avoiding areas that are bony, bruised, sore, red, scarred, or hard.
- Cleanse injection area with an alcohol swab/pad and let dry for 30 seconds before administering the drug.
- Dispose of needles in an FDA-approved sharps disposal container after use.
- Keep a journal of their symptoms and note improved or worsening symptoms.
- Report symptoms of fluid retention, including swelling in legs and feet, weight gain, and shortness of breath, or other symptoms such as constipation, fatigue, dry skin, increased thirst, polyuria, blurred vision, muscle pain, and/or tingling in hands and feet to their health care provider because these may represent an adverse reaction to the drug.
- Speak to their health care provider if they are pregnant or plan on becoming pregnant before starting these drugs because they can impact the fetus.
- Store out of reach from children and away from heat, moisture, and light.
The client taking a growth hormone suppressant should not:
- Dispose of needles or sharps container in the household trash.
- Reuse needles.
- Stop taking the drug unless directed by the health care provider because this drug class replaces or suppresses the body’s growth hormone.