Medical therapy is most often used if surgery does not result in a cure, and sometimes, it is used to shrink large tumors before surgery. Three medication groups are used to treat acromegaly.
Somatostatin analogs (ssas) are the first medication group used to treat acromegaly. They shut off growth hormone (GH) production and are effective in lowering GH and insulin-like growth factor 1 (IGF-I) levels in 50 to 70 percent of patients. Ssas also reduce tumor size in around 0 to 50 percent of patients but only to a modest degree. Several studies have shown that ssas are safe and effective for long-term treatment and in treating patients with acromegaly caused by nonpituitary tumors. Long-acting ssas are given by an intramuscular injection once a month.
Digestive problems-such as loose stools, nausea, and gas-are a side effect in about half of people taking ssas. However, effects are usually temporary and rarely severe. About 10 to 20 percent of patients develop gallstones, but gallstones do not usually cause symptoms. In rare cases, treatment can result in elevated blood glucose levels. More commonly, ssas reduce the need for insulin and improve blood glucose control in some people with acromegaly who already have diabetes.
The second medication group is the GH receptor antagonists (ghras), which interfere with the action of GH. They normalize IGF-I levels in more than 90 percent of patients. They do not, however, lower GH levels. Given once a day through an injection, ghras are usually well tolerated by patients. The long-term effects of these drugs on tumor growth are still under study. Side effects can include headaches, fatigue, and abnormal liver function.
Dopamine agonists make up the third medication group. These drugs are not as effective as other medications at lowering GH or IGF-I levels, and these drugs normalize IGF-I levels in only a minority of patients. Dopamine agonists are sometimes effective in patients who have mild degrees of excess GH and have both acromegaly and hyperprolactinemia-too much of hormone prolactin. Dopamine agonists can be used in combination with ssas. Side effects can include nausea, headache, and light-headedness.
This answer is based on source information from the National Institute of Diabetes and Digestive and Kidney Diseases.