Terguride: partial dopamine agonist in the treatment of Parkinson's disease.
In an open trial, 15 patients with PD (mostly stage V) were treated with the partial DA agonist, terguride, a derivative of lisuride. To the basic therapy, consisting of L-dopa plus benserazide and amantadine, a slowly increasing dosage of TDHL up to a maximum of 1.5 mg/day t.i.d. was added. There were 3 drop-outs; 12 patients completed the trial which lasted for 12 weeks. At this time a significant improvement in total score, bradykinesia, and functional score was seen, as well as a marked improvement in tremors score in the patients who showed this symptom (Columbia Rating Scale). As side-effects, dyskinesias occurred in two patients, psychotic symptoms in one, and marked orthostatic symptoms in one patient. No significant differences before and after 12 weeks TDHL treatment were found in the concentrations of noradrenaline, adrenaline, serotonin, and 5-hydroxy-indole-acetic-acid in plasma. It is concluded that TDHL is effective even in advanced stages of PD, and it is speculated that partial DA agonists may become important in the treatment of PD and might possibly have an advantage over "classical" DA agonists.