Medical Management of Acromegaly

Acromegaly is a rare hormonal disorder that occurs due to excessive amounts of growth hormone after the completion of normal growth. The most common cause of acromegaly is a benign tumor (adenoma) in the pituitary gland that produces growth hormone.

Excess growth hormone can cause a wide range of symptoms. Patients with acromegaly can classically experience enlarged hands and feet, coarsening of facial features, deepening of the voice, thickened skin, excessive sweating, and fatigue.

In this article we will review some of the medications that may be prescribed by your physician to manage acromegaly. The goal of medical intervention is to control growth hormone levels and improve symptoms. Although medications may help to treat your condition, they are typically not as effective as surgery in achieving long-term control of acromegaly.

Acromegaly treatment options include surgery, radiation therapy, and medications. The most effective treatment option is usually transsphenoidal surgery.

This procedure is minimally invasive and involves removing the pituitary tumor responsible for the overproduction of growth hormone. The procedure is performed using long instruments inserted into your nose, with success rates ranging from 70-80%. 

If the tumor has been incompletely removed, the tumor recurs, or if surgery is deemed too risky, radiation therapy or medications may be recommended. Radiation therapy is typically delivered as stereotactic radiosurgery, which uses targeted radiation beams to shrink the pituitary tumor and prevent further growth.

Medications such as somatostatin analogs (e.g., octreotide, lanreotide), dopamine agonists (e.g., cabergoline, bromocriptine), and growth hormone antagonists (pegvisomant) can be used to lower growth hormone levels or block its effects.

Medications used to treat acromegaly work by reducing the amount of growth hormone produced or blocking the effects of growth hormone. This can help to improve symptoms and reduce the risk of complications associated with acromegaly.

There are currently three classes of drugs used for the treatment of acromegaly: somatostatin analogs, dopamine agonists, and growth hormone antagonists.

Somatostatin analogs are a class of medications that work by mimicking the action of somatostatin, a natural hormone that inhibits the release of growth hormone and other hormones from the pituitary gland.

Octreotide and lanreotide are usually given by injection, either in the fatty tissue just under the skin (subcutaneously) or in the muscle (intramuscularly) and are typically administered every 4 weeks. The most common injection sites for octreotide and lanreotide are the upper outer quadrant of the buttocks or the outer thigh.

These drugs can effectively reduce the levels of growth hormone in the blood, leading to improvement in symptoms. They can also reduce the size of pituitary tumors in some cases.

Somatostatin analogs are generally well-tolerated, but may cause side effects such as abdominal discomfort, nausea, diarrhea, and injection site reactions. Long-term use of these drugs may also lead to gallstones or impaired glucose tolerance in some people.

Dopamine agonists, such as cabergoline and bromocriptine, are a class of medications that stimulate dopamine receptors and suppress the production of growth hormone though their exact mechanism of action is unclear.

Cabergoline and bromocriptine are the most commonly used dopamine agonists for the treatment of acromegaly. They are usually given orally and may be used alone or in combination with other medications such as somatostatin analogs.

Dopamine agonists are generally less effective than somatostatin analogs in reducing growth hormone levels in patients with acromegaly.

However, they may be a useful alternative for patients who cannot tolerate somatostatin analogs or for whom somatostatin analogs are not effective.

Some of the common side effects of dopamine agonists include nausea and vomiting, headaches, dizziness, fatigue, mood changes, and sleep disturbances.

Growth hormone antagonists work by binding to the growth hormone receptor and blocking growth hormone activity. This decreases the production of insulin-like growth factor 1 (IGF-1), which is responsible for many symptoms of acromegaly.

Pegvisomant, the primary medication in this class, is usually given by injection and can be effective in reducing symptoms of acromegaly. It may even help to improve glucose levels in patients with acromegaly-associated diabetes.

In recent studies, almost 90% of patients have shown normalization of their IGF-1 levels.

While pegvisomant is generally well-tolerated, it can have side effects, including headache, fatigue, and elevated liver enzymes. It is also relatively expensive and requires regular monitoring of IGF-1 levels to ensure appropriate dosing.

The effectiveness of medications in treating acromegaly varies depending on the specific medication used and the individual patient's response. It is important to note that not all individuals are suitable candidates for these medications.

To determine the most safe and effective treatment plan, consult with your physician regarding the appropriate dosage, duration, and combination of medications. Additionally, it is crucial to inform your doctor of any pre-existing medical conditions or current medications and to report any side effects.

Transsphenoidal surgery is the most effective treatment option for acromegaly and involves accessing the pituitary gland through the nose and removing the tumor. This surgery is often successful at reducing growth hormone levels and improving symptoms and is thus typically the go-to treatment option.

However, surgery may not be appropriate for all patients. The final treatment plan should be made after a thorough discussion with your medical team.

• Medications used to treat acromegaly work by reducing the amount of growth hormone produced or blocking the effects of growth hormone.
• Somatostatin analogs, dopamine agonists, and growth hormone antagonists are the three broad classes of medications used in the treatment of acromegaly.  
• Combination therapy involving surgery, radiation therapy, and medications may be used depending on the individual circumstance.
• Transsphenoidal surgery remains the first-line treatment option for acromegaly.

• Pituitary Network Association: Acromegaly
• The Pituitary Foundation [UK]: Acromegaly
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): Acromegaly
• National Health Service (NHS) [UK]: Acromegaly