The synaptic significance of metoclopramide induced dyskinetic-dystonic head and neck movements in pregnancy

Abstract

Two young, pregnant women presenting dyskinetic-dystonic crises limited to head and neck (HNDD) due to metoclopramide (MP) were observed. Evidence has been brought for the specific extrapyramidal effect of dyskinetic-dystonic head and neck movements induced by MP in young females. The synaptic action of MP differs from that of the generally accepted dopamine receptor blocking neuroleptics such as the phenothiazines. Concomittant quasi opposing neuroleptic and nonneuroleptic like effects of this drug can not support the mechanism of dopamine receptor blockade as the explanation of the synaptic effect. The concept of "dopamine receptor imbalance" may explain the synaptic action of the metoclopramide.

Metoclopramide-Induced Acute Dystonic Reactions May Be Associated With the CYP2D6 Poor Metabolizer Status and Pregnancy-Related Hormonal Changes

“…Moreover, pregnancy-related physiological changes may decrease the CYP2D6 activity further in the poor metabolizers (Wadelius et al, 1997). Hence, we theorize that the combined influence of CYP2D6 poor metabolism and pregnancy-induced rises in the estrogen levels may create a delicate, hyper-dopaminergic state that is easily upset by metoclopramide (Askenasy et al, 1978), resulting in acute dystonia ( Figure 1 ).…”

Serum dopamine beta hydroxylase activity and metoclopramide provocative test in torsion dystonia

“…This activity is responsable for the antiemetic and gastrointestinal regulating effect and stimulation of lactation. Of 34 published cases with extrapyramidal effects, 30 cases had head and neck dystonia [2,3,4,5,6,7,8] (Table 1). Because of this we used MP as a provocative test in families with torsion dystonia (TD).…”

“…In these three cases the serum DBH activity doubled and tripled. It is suggested that the MP induced elevation of serum DBH activity in relatives of TD patients indicates a genetic disposition.Metoclopramide (MP) occasionally leads to extrapyramidal effects comprising dystonia of the head and neck [1,2,3,4,5,6,7,8]. MP is a procainamide derivative (Fig.…”

Juvenile Parkinson's disease and its response to L-dopa therapy

“…A dystonic foot onset in naive parkinsonians is a rare phenomenon, but we are used to attributing dystonia in PD patients as an emerging side-effect of longterm levodopa therapy (Askenasy et al, 1978). In patients, I, II, and III, the dystonic foot appeared at a very young age, and consisted of arching and inversion of the sole of short duration and reversed by levodopa.…”