Non-functioning pituitary adenomas in general do not respond to medical treatment20. Patients with a prolactinoma have a treatment response of 95% on dopamine-agonists and therefore medical treatment is the first choice.
Acromegalic patients respond in 65% of the cases on somatostatin analogues and in more than 90% on Pegvisomant, a GH-receptor antagonist. Side-effects of somatostatin analogues are diarrhea in 11%, flatulence in 8%, hair loss in 8%, episodically abdominal cramps in 3%, and gallbladder abnormalities in <10% of the patients. Pegvisomant is expensive and in general does not result in tumour shrinkage21 and may even result in tumour growth22.
In case of Cushing’s disease, medication is directed at decreasing adrenal steroid secretion (e.g. ketoconazole, metyrapone, aminoglutethimide). These drugs frequently lose effectiveness when the decrease in cortisol secretion results in enhanced ACTH secretion, leading to escape from the competitive blockade on adrenal steroid biosynthesis. Long-term ketoconazole is not recommended because of the risk of liver function impairment.
Mortality due to medication has not been reported.