Pituitary Drugs

The pituitary gland is located in the skull in the bony sella turcica under a layer of dura mater. It is divided into three lobes: an anterior lobe, a posterior lobe, and an intermediate lobe. The anterior lobe produces stimulating hormones in response to hypothalamic stimulation. The pituitary lobe stores ADH and oxytocin. The intermediate lobe produces endorphins and enkephalins to modulate pain perception.

Pituitary agents include drugs affecting anterior (further divided into growth hormone agonists and growth hormone antagonists) and posterior pituitary hormones.

Drugs that affect anterior pituitary hormones mimic or antagonize the effects of specific pituitary hormones. They are used as replacement therapy, for diagnostic purposes, and for blocking the effects of anterior pituitary hormones.

The anterior pituitary hormone that is most commonly used pharmacologically is growth hormone (GH).

Table of Contents

• Pituitary Agents: Generic and Brand Names
• Growth Hormones Agonists
  • Therapeutic Action
  • Indications
  • Pharmacokinetics
  • Contraindications and Cautions
  • Adverse Effects
  • Interactions
  • Nursing Considerations
    • Nursing Assessment
    • Nursing Diagnoses and Care Planning
    • Nursing Implementation with Rationale
    • Evaluation
• Growth Hormone Antagonists
  • Disease Spotlight: Hyperpituitarism
  • Therapeutic Action
  • Indications
  • Pharmacokinetics
  • Contraindications and Cautions
  • Adverse Effects
  • Interactions
  • Nursing Considerations
    • Nursing Assessment
    • Nursing Diagnosis 
    • Implementation with Rationale
    • Evaluation
• Drugs Affecting Posterior Pituitary Hormones
  • Therapeutic Action
  • Indications
  • Pharmacokinetics
  • Contraindications and Cautions
  • Adverse Effects
  • Interactions
  • Nursing Considerations
    • Nursing Assessment
    • Nursing Diagnosis and Care Planning
    • Nursing Implementation with Rationale
    • Evaluation
• Recommended Resources
• See Also
• References and Sources

Pituitary Agents: Generic and Brand Names

Here is a table of commonly encountered pituitary agents, their generic names, and brand names:

• Anterior pituitary hormone drugs
  • Growth Hormone Agonists
    • somatropin (Nutropin, Saizen, Humatrope)
  • Growth Hormone Antagonists
    • bromocriptine (Parlodel)
    • lantreolide (Somatuline Depot)
    • octreotide (Sandostatin)
    • pegvisomant (Somavert)
  • Other drugs affecting anterior pituitary hormones
    • chorionic gonadotropin (Chorex)
    • corticotropin (Acthar)
    • cosyntropin (Cortrosyn)
    • menotropin (Pergonal)
    • thyrotropin alfa (Thyrogen)
• Posterior Pituitary Hormone Drugs
  • conivaptan (Vaprisol)
  • desmopressin (DDVAP)
  • tolvaptan (Samsca)

Growth Hormones Agonists

• Growth Hormone Agonists are responsible for linear skeletal growth, growth of internal organs, protein synthesis, and stimulation of processes required for normal growth.Disease Spotlight: GH Deficiency
• Hypopituitarism is often seen as GH deficiency before any other signs and symptoms occur. It occurs as a result of the following: developmental abnormalities, congenital defects of the pituitary, circulatory disturbances (e.g. hemorrhage), acute or chronic inflammation of the pituitary, and pituitary tumors.
• Dwarfism is the GH deficiency in children which results to short stature.
• Somatotropin deficiency syndrome (SDS) is a condition in adults with hypopituitarism caused by pituitary tumors or trauma, or may have been treated for GH deficiency as children, resulting in a shutdown of the pituitary production of somatotropin.

Therapeutic Action

The desired and beneficial action of GH agonists is:

• replacing human GH and stimulate skeletal growth, growth of internal organs, and protein synthesis.

Indications

GH agonists are indicated for the following medical conditions:

• long-term treatment of children with growth failure associated with various deficiencies, girls with Turner’s syndrome, AIDS wasting and cachexia, GH deficiency in adults, and treatment of growth failure in children of small gestational age who do not achieve catch-up growth by 2 years of age.
• Somatropin (Nutropin, Saizen, Genotropin, Serostim) and somatropin rDNA origin (Zorbtive) are used for GH replacement today.

Pharmacokinetics

Here are the characteristic interactions of GH agonists and the body in terms of absorption, distribution, metabolism, and excretion:

Route	Onset	Peak	Duration
IM, subcutaneous	Varies	5-7.5 h

Half-life (T1/2)	Metabolism	Excretion
15-20 min	Liver	Urine, Feces

Contraindications and Cautions

The following are contraindications and cautions for the use of GH agonists:

• Allergy to any component of the drug. To prevent hypersensitivity reactions.
• Closed epiphyses and cranial lesions. Risk of serious complications with somatropin.
• Abdominal surgery and acute illness secondary to complications of open heart surgery. Potential problems with healing.
• Pregnancy or lactation. Potential adverse effects on the fetus.

Adverse Effects

Use of GH agonists may result to these adverse effects:

• development of antibodies to GH
• inflammation and autoimmune-type reactions (swelling, joint pain)
• endocrine reactions (hypothyroidism, insulin resistance).

Interactions

The following are drug-drug interactions involved in the use of GH agonists:

• change in metabolism with drugs using P450 liver enzyme system

Nursing Considerations

Here are important nursing considerations when administering GH agonists:

Nursing Assessment

These are the important things the nurse should include in conducting assessment, history taking, and examination:

• Assess for contraindications or cautions (e.g. history of allergy, pregnancy, serious infection after open heart surgery, etc.) to avoid adverse effects.
• Assess height, weight, thyroid function tests, glucose tolerance tests, and GH levels to determine baseline status before beginning therapy and for any potential adverse effects.   

Nursing Diagnoses and Care Planning

Here are some of the nursing diagnoses that can be formulated in the use of this drug for therapy:

• Imbalanced nutrition: less than body requirements related to metabolic changes
• Acute pain related to need for injections

Nursing Implementation with Rationale

These are vital nursing interventions done in patients who are taking GH agonists:

• Reconstitute the drug following manufacturer’s directions because individual products vary; administer IM or SQ as ordered for appropriate drug delivery.
• Monitor response closely to determine need for dose adjustment.
• Monitor thyroid function, glucose tolerance, and GH levels periodically to monitor endocrine changes and to institute treatment as needed.
• Provide comfort measures to help patient cope with the drug effects. 
• Provide patient education (storage, preparation, administration techniques) about drug effects and warning signs to report to enhance patient knowledge and to promote compliance.   

Evaluation

Here are aspects of care that should be evaluated to determine effectiveness of drug therapy:

• Monitor patient response to therapy (return of GH levels to normal, growth and development).
• Monitor for adverse effects (e.g. nutritional imbalance, hypothyroidism).
• Evaluate patient understanding on drug therapy by asking patient to name the drug, its indication, and adverse effects to watch for.
• Monitor patient compliance to drug therapy

Growth Hormone Antagonists

• Growth Hormone antagonists are used in treating GH hypersecretion (hyperpituitarism) caused by pituitary tumors.

Disease Spotlight: Hyperpituitarism

• GH hypersecretion is usually caused by pituitary tumors and can occur at any time of life.
• Gigantism occurs before the epiphyseal plates of the long bones fuse and cause acceleration in linear skeletal growth. Individuals with gigantism can reach 7 to 8 feet in height with fairly normal body proportions.
• Acromegaly is a form of hyperpituitarism after epiphyseal closure (adults). As linear growth is impossible, hypersecretion of GH causes enlargement in the peripheral parts of the body such as hands and feet as well as internal organs (heart).

Therapeutic Action

The desired and beneficial action of GH antagonists is:

• acting directly on postsynaptic dopamine receptors in the brain to inhibit GH secretion
• Octreotide and lanreotide are somatostatin analogues which are more potent in inhibiting GH release with less of an inhibitory effect on insulin release. They are used instead of somatostatin.

Indications

GH antagonists are indicated for the following medical conditions:

• Treatment of Parkinson’s disease, hyperprolactinemia associated with pituitary adenomas, female infertility associated with hyperprolactinemia, and acromegaly; short-term treatment of amenorrhea or galactorrhea.
• Bromocriptine is a semisynthetic ergot alkaloid and a dopamine agonist which is frequently used to treat acromegaly. It may also be used as adjunct to irradiation.

Pharmacokinetics

Here are the characteristic interactions of GH antagonists and the body in terms of absorption, distribution, metabolism, and excretion:

Route	Onset	Peak	Duration
PO	Varies	1-3 h	14 h

Half-life (T1/2)	Metabolism	Excretion
60-90 min	Liver	Bile

Contraindications and Cautions

The following are contraindications and cautions for the use of GH antagonists:

• Allergy to any component of the drug. To prevent hypersensitivity reactions.
• Pregnancy or lactation. Potential adverse effects on the fetus.
• Diabetes, thyroid dysfunction. May be exacerbated by blocking GH.

Adverse Effects

Use of GH antagonists may result to these adverse effects:

• CNS: headache
• CV: sinus bradycardia, arrhythmias
• GI: nausea, vomiting, abdominal cramps, constipation, diarrhea, acute cholecystitis, cholestatic jaundice, biliary tract obstruction, pancreatitis
• Others: decreased glucose tolerance, inflammation at injection sites

Interactions

The following are drug-drug interactions involved in the use of GH antagonists:

• Erythromycin. Increased toxicity with bromocriptine
• Phenothiazine. Decreased effectiveness of bromocriptine
• Opioids. Higher doses of pegvisoman will be required

Nursing Considerations

Here are important nursing considerations when administering GH antagonists:

Nursing Assessment

These are the important things the nurse should include in conducting assessment, history taking, and examination:

• Assess for contraindications or cautions (e.g. history of allergy to the drug,  other endocrine disturbances, pregnancy and lactation, etc.) to avoid adverse effects.
• Assess orientation, affect, and reflexes; blood pressure, pulse, and orthostatic blood pressure; abdominal examination; glucose tolerance tests; and GH levels to determine baseline status before beginning therapy and for any potential adverse effects.   

Nursing Diagnosis

Here are some of the nursing diagnoses that can be formulated in the use of this drug for therapy:

• Imbalanced nutrition: more than body requirements related to metabolic changes
• Acute pain related to need for injections

Implementation with Rationale

These are vital nursing interventions done in patients who are taking GH antagonists:

• Reconstitute the drug following manufacturer’s directions because individual products vary; administer IM or SQ as ordered for appropriate drug delivery.
• Inject lanreotide deep into subcutaneous fat in the superior quadrant of the buttocks and alternate from right to left to ensure proper drug delivery and prevent local reactions. 
• Monitor thyroid function, glucose tolerance, and GH levels periodically to monitor endocrine changes and to institute treatment as needed.
• Arrange for baseline and periodic ultrasound evaluation of gallbladder if using octreotide or lanreotide to detect any gallstone development and to arrange for appropriate treatment.
• Provide comfort measures to help patient cope with the drug effects. 
• Provide patient education about drug effects and warning signs to report to enhance patient knowledge and to promote compliance.   

Evaluation

Here are aspects of care that should be evaluated to determine effectiveness of drug therapy:

• Monitor patient response to therapy (return of GH levels to normal).
• Monitor for adverse effects (e.g. nutritional imbalance).
• Evaluate patient understanding on drug therapy by asking patient to name the drug, its indication, and adverse effects to watch for.
• Monitor patient compliance to drug therapy.

Drugs Affecting Posterior Pituitary Hormones

• The posterior pituitary stores two hormones produced by the hypothalamus (antidiuretic hormone or vasopressin [ADH] and oxytocin).
• ADH possesses antidiuretic, hemostatic, and vasopressor properties. It is the hormone affected in diabetes insipidus, a condition characterized by production of a large amount of dilute urine containing no glucose.

Therapeutic Action

The desired and beneficial actions of posterior pituitary agents are:

• Pressor and antidiuretic effect by causing the cortical and medullary parts of the collecting duct to become permeable to water, thereby increasing water reabsorption and decreasing urine formation.
• Increasing levels of clotting factor VIII

Indications

Posterior pituitary agents are indicated for the following medical conditions:

• Treatment of neurogenic diabetes insipidus and hemophilia A

Pharmacokinetics

Here are the characteristic interactions of posterior pituitary agent and the body in terms of absorption, distribution, metabolism, and excretion:

Route	Onset	Peak	Duration
Oral	1 h	60-90 min	7 h
IV, subcutaneous	30 min	90-120 min	Varies
Nasal	15-60 min	1-5 h	5-21 h

Half-life (T1/2)	Metabolism	Excretion
7.8 min, 75.5 min (IV) 1.5-2.5 h (oral) 3.3-3.5 h (nasal	Tissues	Unknown

Contraindications and Cautions

The following are contraindications and cautions for the use of posterior pituitary agents:

• Allergy to any component of the drug. To prevent hypersensitivity reactions.
• Severe renal dysfunction. Can alter the effects of the drug
• Any known vascular disease. Can be exacerbated by the effects of the drug on vascular smooth muscle
• Pregnancy. Risk of premature uterine contractions.
• Lactation. Potential adverse effects to the neonate.

Adverse Effects

Use of posterior pituitary agents may result to these adverse effects:

• Water intoxication. Drowsiness, light-headedness, headache, coma, convulsions
• GI: abdominal cramps, flatulence, nausea, vomiting, constipation, dry mouth
• Local reaction at injection site

Interactions

The following are drug-drug interactions involved in the use of posterior pituitary agents:

• Carbamazepine, chlorpropamide. Increased antidiuretic effects if with desmopressin
• Digoxin, ACEI, ARBs, potassium-sparing diuretics. Risk of hyperkalemia with tolvaptan and conivaptan
• Telithromycin. Severe tolvaptan toxicity.

Nursing Considerations

Here are important nursing considerations when administering posterior pituitary agents:

Nursing Assessment

These are the important things the nurse should include in conducting assessment, history taking, and examination:

• Assess for contraindications or cautions (e.g. history of allergy, pregnancy, renal dysfunction, etc.) to avoid adverse effects.
• Assess skin for lesions; orientation, affect, and reflexes; blood pressure and pulse; respiration and adventitious sounds; abdominal examination; renal function tests; and serum electrolytes, to determine baseline status before beginning therapy and for any potential adverse effects.    

Nursing Diagnosis and Care Planning

Here are some of the nursing diagnoses that can be formulated in the use of this drug for therapy:

• Altered urinary elimination
• Changes in fluid volume related to water retention or excretion

Nursing Implementation with Rationale

These are vital nursing interventions done in patients who are taking posterior pituitary agents:

• Monitor patient fluid volume to watch for signs of water intoxication and fluid excess or excessive fluid loss.
• Monitor patient with vascular disease for any sign of exacerbation to provide for immediate treatment.
• Monitor condition of nasal passages if given intranasally to observe for nasal ulceration, which can occur and could affect drug absorption.
• Provide comfort measures to help patient cope with the drug effects. 
• Provide patient education about drug effects and warning signs to report to enhance patient knowledge and to promote compliance.   

Evaluation

Here are aspects of care that should be evaluated to determine effectiveness of drug therapy:

• Monitor patient response to therapy (maintenance of fluid balance).
• Monitor for adverse effects (e.g. water intoxication, GI problems).
• Evaluate patient understanding on drug therapy by asking patient to name the drug, its indication, and adverse effects to watch for.
• Monitor patient compliance to drug therapy.

Recommended Resources

Our recommended nursing pharmacology resources and books:

Disclosure: Included below are affiliate links from Amazon at no additional cost from you. We may earn a small commission from your purchase which will help support us. Thank you! For more information, check out our privacy policy.

See Also

Here are other nursing pharmacology study guides:

• Nursing Pharmacology – Study Guide for Nurses
  Our collection of topics related to nursing pharmacology
• Pharmacology Nursing Mnemonics & Tips
  These nursing mnemonics aim to simplify the concepts of pharmacology through the use of a simple, concise guide.
• Generic Drug Name Stems Cheat Sheet
  Learn about these generic drug name stems to help you make sense of drugs easier!
• Common Drugs and Their Antidotes
  A guide to drug antidotes that nurses should be familiar about.
• IV Fluids and Solutions Guide & Cheat Sheet
  Get to know the different types of intravenous solutions or IV fluids in this guide and cheat sheet.
• Drug Dosage Calculations NCLEX Practice Questions (100+ Items)
  Care to take the challenge? This quiz aims to help students and registered nurses alike grasp and master the concepts of medication calculation.

Drug Guides ^NEW!

Individual drug guides and nursing considerations for the most common medications used in nursing pharmacology:

• Acetaminophen (Tylenol)
• Aspirin
• Atorvastatin (Lipitor)
• Enoxaparin (Lovenox)
• Furosemide (Lasix)
• Gabapentin
• Hydromorphone (Dilaudid)
• Lisinopril
• Metoprolol
• Morphine

References and Sources

References and sources for this pharmacology guide for Pituitary Agents:

• Karch, A. M., & Karch. (2011). Focus on nursing pharmacology. Wolters Kluwer Health/Lippincott Williams & Wilkins. [Link]
• Katzung, B. G. (2017). Basic and clinical pharmacology. McGraw-Hill Education.
• Lehne, R. A., Moore, L. A., Crosby, L. J., & Hamilton, D. B. (2004). Pharmacology for nursing care.
• Smeltzer, S. C., & Bare, B. G. (1992). Brunner & Suddarth’s textbook of medical-surgical nursing. Philadelphia: JB Lippincott.