REGLAN (metoclopramide) can cause Tardive Dyskinesia, a serious and often irreversible movement disorder list of signs and symptoms include:

Jaw movements
Chewing-like movements
Facial grimacing
Tongue movements
Tongue protrusion
Lip movements
Lip smacking
Lip puckering
Lip pursing
Rapid eye blinking
Rapid movements of the arms, legs, and trunk.
Involuntary finger movements
Involuntary facial movements
Abnormal facial movements
Grimacing
Sticking out tongue
Sucking of the lips
Smacking of the lips
Involuntary rapid arm movements
Involuntary rapid leg movements
Dystonia

Other Serious Side Effects:

Mental depression
Other types of severe movement disorders
Unexplained abdominal pain
Breathing problems
Convulsions and seizures
Cardiovascular conditions, such as elevated blood pressure or rapid pulse
Blood problems, especially for infants
An allergic reaction, such as swelling of the tongue, throat or hives
Anxiety or insomnia
Depression
Changes in vision
An irregular heartbeat
Seizures or hallucinations

In some established cases of Tardive Dyskinesia, Reglan (Metoclopramide) has been shown to mask the signs and not become apparent until discontinuation of the Drug.