Dopamine agonists are effective in some patients with
acromegaly and in this condition treatment is considered to be chronic. We describe two acromegalic patients who responded adequately to the long-acting
dopamine agonist cabergoline, but surprisingly maintained normal GH and
IGF-I levels once
therapy was discontinued after 42 and 76 months because of possibly related side effects. A 32-year-old woman with mild
acromegaly (
IGF-I: 423 microg/l, GH after OGTT: 2.5 microg/l,
adenoma 4 mm) was treated with
cabergoline as primary
therapy and reached safe GH levels (2 microg/l or less) and normal
IGF-I levels with 3.5 mg
cabergoline weekly. After 42 months of
therapy the patient experienced a progressive decrease of libido, which she attributed to the intake of
cabergoline. After stopping medication, serum levels of GH and
IGF-I remained normal during the following 2.5 years. A 53-year-old man with moderate
acromegaly (serum
IGF-I: 547 microg/l, GH after OGTT: 5.9 microg/l,
adenoma 7 mm) preferred
cabergoline as primary
therapy. Serum GH levels below 2 microg/l and normal levels of
IGF-I were obtained with 3.5 mg
cabergoline weekly. When the patient experienced severe stomach pains after 76 months of treatment,
cabergoline was held responsible and discontinued. Serum GH and
IGF-I did not increase again and stayed at the same level during a follow-up of 5.5 years. These two cases demonstrate that acromegalic patients with a good response to
cabergoline may occasionally remain in remission after stopping
therapy. This phenomenon has previously only been described in patients with a
prolactinoma.