Medical Therapy

Medical Therapy

Medical therapy for acromegaly uses medication to prevent growth hormone (GH) from being produced and released by the pituitary gland or from reaching the other tissues in the body. Medical therapy can also reduce the production of IGF-1 (insulin-like growth factor-1) hormone by blocking the effects of GH or by lowering the levels of both GH and prolactin.

Types of medical therapy

The three types of medical therapy for the treatment of acromegaly are somatostatin analogues, GH receptor antagonists and dopamine agonists. Each type of medication works differently to control GH levels.

  • Somatostatin analogues work in a similar way to the hormone somatostatin that is made by the hypothalamus in the brain. Somatostatin reduces the amount of GH production and release from the pituitary gland.
    • There are two somatostatin analogues available: lanreotide and octreotide.
  • GH receptor antagonists lower the amount of IGF-1 hormone, mainly in the liver, by blocking the effects of GH. GH receptor antagonists do not lower the amount of GH in the bloodstream. They work by lowering the amount of IGF-1 hormone instead.
    GH receptor antagonists are usually prescribed if somatostatin analogues are not working or cause unmanageable side effects.

    • There is one GH receptor antagonist available: pegvisomant.
  • Dopamine agonists prevent the adenoma from releasing GH and prolactin.
    • The dopamine agonists are bromocriptine and cabergoline.

Administration and dosing frequency

Each medication is administered differently and at different times.

Somatostatin Analogues GH Receptor Antagonist Dopamine Agonists
Lanreotide Octreotide Pegvisomant Bromocriptine Cabergoline (can be used if the adenoma is also causing high levels of prolactin)
Administration technique Deep-subcutaneous injection (deep under the skin) Deep intra-gluteal injection (into the muscle) Subcutaneous injection (just under the skin) By mouth By mouth
Administration location Upper, outer area of the buttock or upper, outer thigh The muscle of the buttocks Upper arm, upper thigh, abdomen and buttocks Not applicable Not applicable
Administration frequency Every 4 weeks Every 4 weeks Every day Two or three times a day Once or twice a week
Administered by Self-injection, healthcare professional or trained person Healthcare professional Self-injection Self Self

It is important to take your medication exactly as prescribed by your doctor.

Side effects*

All medications have side effects. The most serious side effects associated with somatostatin analogues are:

  • High blood sugar or low blood sugar if you have diabetes
  • Formation of gallstones
  • Drug interaction with cyclosporin

The most common side effects associated with somatostatin analogues are:

  • Diarrhea
  • Abdominal pain
  • Nausea
  • Flatulence
  • Pain at the injection site

The most serious side effects associated with GH receptor antagonists are due to liver damage:

  • Yellowing of the skin or whites of the eyes
  • Darkening of urine
  • Unexplained fatigue, nausea, vomiting or pain in the abdomen
  • Elevation in liver enzymes

The most common side effects associated with GH receptor antagonists are:

  • Pain
  • Infection
  • Injection site reactions
  • Flu-like symptoms
  • Nausea

The most serious side effects associated with dopamine agonists are:

  • Pleuropulmonary and/or retroperitoneal fibrosis (scar tissue formation in the lining of the lungs and/or abdominal cavity)
  • High or low blood pressure
  • Sudden onset of sleep
  • Heart valve damage (usually with very high doses)

The most common side effects associated with dopamine agonists are:

  • Headache
  • Vertigo
  • Fatigue
  • Lightheadedness
  • Hypotension
  • Nausea
  • Abdominal cramps
  • Constipation
  • Diarrhea
  • Nasal congestion