What Is Acromegaly?
- Acromegaly is a growth disorder caused by excessive production of growth hormone (GH) by the pituitary gland.
- The pituitary gland is a hormone-producing organ at the base of the brain, behind the eyes, and at the middle of the brain between the ears.
- Children cannot grow to normal height if they do not have enough GH, but too much causes prepubertal children to develop giantism, a condition in which the entire body or any of its parts grow too large.
- In adults, too much GH causes acromegaly, a disorder in which parts of the body, especially the head, face, hands, and feet, gradually get bigger.
- GH affects growth by stimulating the formation of other hormones. These hormones are mostly made by the liver in response to GH stimulation and are called somatomedins (somatotropin-mediating hormones or insulinlike growth factors).
What Causes Acromegaly?
In most cases, excess growth hormone (GH) is caused by tumors on the pituitary gland.
What Are the Risks of Acromegaly?
Acromegaly is a severe disease, but it is often difficult to diagnose because it develops slowly over many years. People usually do not know they have acromegaly until they are 40 years old. The rate of acromegaly-caused complications and death is high once they become clinically obvious. The condition can lead to heart disease, vascular disease, stroke, lung disorders, and an increased risk of colon or breast cancers.
Medical Treatment of Acromegaly
Treatment consists of surgery, medications, and, sometimes, radiation. Lifestyle changes to avoid further risks of developing associated complications, such as heart disease, vascular disease, stroke, lung disorders, and/or cancers, should also be part of therapy. Lifestyle changes may include smoking cessation, low-fat diets, and exercise.
- How GH inhibitors work: These drugs decrease the effect of excessive growth hormone (GH) by blocking GH from binding to cell receptors.
- Who should not use these medications: Individuals allergic to GH inhibitors should not take them.
- Use: Pegvisomant is self-administered by daily subcutaneous (shallow injection under the skin) injections.
- Drug or food interactions: Pegvisomant may decrease insulin or oral antidiabetic drug effects. Individuals who take narcotic analgesics, such as morphine or codeine, may require higher doses of pegvisomant.
- Side effects: The drug container top contains latex. Pegvisomant may cause certain GH-secreting tumors to grow more readily. Additionally, this drug may induce GH deficiency and/or increase liver enzyme levels. GH levels must be monitored to help guide dose adjustments. Liver enzyme levels must also be monitored.
- How somatostatinlike drugs work: These drugs work by binding to somatostatin receptors, thus causing decreased response to the secretion of growth hormone (GH).
- Who should not use these medications: Individuals allergic to somatostatinlike drugs should not take them.
- Use: Octreotide is administered by daily or monthly injections.
- Drug or food interactions: Octreotide may reduce the effect of cyclosporine. Individuals taking insulin, oral antidiabetic drugs, beta-blockers, or calcium channel blockers may require dosage adjustments of these drugs. Octreotide must be used with caution when taking drugs that treat heart rhythm problems or drugs that may cause heart rhythm disturbances, such as those used to treat depression or schizophrenia.
- Side effects: Common side effects include nausea, abdominal pain, diarrhea, and increased risk of gallstones. Increases or decreases in blood sugar levels or hypothyroidism may occur because of alteration in hormones. Octreotide may cause heart rhythm abnormalities. Lower doses are often required for individuals who are elderly or those with severe kidney disease.
- How dopamine stimulators work: These drugs act on dopamine receptors in the brain.
- Who should not use these medications: Individuals with allergies to dopamine stimulators, poorly controlled high blood pressure, heart disease, and/or blood vessel disorders should not take dopamine stimulators.
- Use: Tablets are swallowed, and the dose is gradually increased.
- Drug or food interactions: Amitriptyline, butyrophenones, imipramine, methyldopa, phenothiazines, and reserpine may decrease dopamine stimulators’ effects. Some drugs used to treat migraine headaches may increase dopamine stimulators’ toxicity.
- Side effects: Side effects include nausea, vomiting, headaches, nasal congestion, and low blood pressure (may cause dizziness or fainting). Tolerance to side effects develops over time. These drugs must be used with caution in people who have kidney or liver disease.
- Lanreotide (Somatuline LA, Somatuline Autogel) is another somatostatinlike drug.
- Ibopamine (Scandine) exerts effects similar to those of dopamine stimulators.