Bromocriptine therapy in acromegaly: use in patients resistant to conventional therapy and effect on serum levels of somatomedin C.

Seven patients with clinically active acromegaly who had not responded completely to previous surgical or radiation therapy were treated with bromocriptine. Bromocriptine was well tolerated; only one of the seven patients discontinued treatment secondary to side effects. Six of the seven patients improved during bromocriptine therapy, although GH levels were normalized in only two patients. All patients had elevated levels of somatomedin C (Sm-C) before therapy even when basal levels of GH were less than 10 ng/ml. One patient normalized both GH and Sm-C during bromocriptine therapy and had an excellent clinical response. Five patients had moderately good clinical responses; four of these patients had substantial falls in GH levels, but Sm-C levels fell minimally if at all in four and actually increased in one patient. In one patient, there was no change in clinical status, GH levels, or Sm-C levels. Thus, the clinical response did not correlate well with changes in Sm-C in most patients. The patterns of response to provocative stimuli of GH secretion in acromegaly were maintained during bromocriptine therapy, as has been previously been reported. Based on our experience, bromocriptine appears to be a useful adjunct in the therapy of acromegaly, even in patients who have had prior ablative therapy.