Rapid regression of macroprolactinomas by the new dopamine partial agonist terguride

Two patients with macroprolactinomas were treated with the partial dopamine agonist, terguride. The prolactin (Prl) levels were lowered very effectively and in both cases the clinical symptoms improved markedly during the first days of treatment. Computerized tomography (CT) and magnetic resonance imaging (MRI) follow-up studies showed distinct tumour shrinkages which were first documented by MRI within 2 weeks of treatment. Tumour residues were, however, still demonstrable by MRI after more than one year respectively 3 months of therapy. In principal, results from both imaging techniques were comparable with the exception of the one year follow-up study of patient 1. In CT no residual tumour mass was visible whereas MRI showed only little reduction when compared to the 30th week scan. Throughout the treatment terguride was well tolerated without any side effects up to a maximal daily dosage of 3 mg given orally. Presumably the partial agonistic features of terguride contributed to the good tolerance of the treatment as compared to that of full dopamine agonists like bromocriptine of lisuride. Thus, these preliminary results indicate that terguride may be a beneficial alternative in the treatment of prolactinomas and other hyperprolactinaemic states.