Diphenidol For Levodopa Induced Nausea and Vomiting

Abstract

To the Editor.— Nausea, anorexia, and vomiting are frequent side effects in the initial phases of therapy with levodopa in parkinsonism. With time, most patients develop a tolerance, and it is possible with small doses and successive increments to reach a therapeutically effective dose without occasionally provoking more than mild nausea and malaise. However, some patients fail to develop significant tolerance despite careful adjustment, and a few particularly sensitive patients develop severe nausea or vomiting even with the initial doses of levodopa. Since these side effects appear to reflect a central action at the medullary vomiting center similar to that of apomorphine hydrochloride and epinephrine1,2a specific antiemetic drug that does not adversely affect the parkinsonian state nor antagonize the therapeutic action of levodopa would be useful. Unfortunately, most of the specific antiemetics presently available are phenothiazine derivatives. Among the few specific antiemetics available that are not also neuroleptic