Metoclopramide should not be used whenever stimulation of gastrointestinal motility might be dangerous, e.g., in the presence of gastrointestinal hemorrhage, mechanical obstruction, or perforation.Metoclopramide is contraindicated in patients with pheochromocytoma because the drug may cause a hypertensive crisis, probably due to release of catecholamines from the tumor.Such hypertensive crises may be controlled by phentolamine.Metoclopramide is contraindicated in patients with known sensitivity or intolerance to the drug.Metoclopramide should not be used in epileptics or patients receiving other drugs which are likely to cause extrapyramidal reactions, since the frequency and severity of seizures or extrapyramidal reactions may be increased.
Mental depression has occurred in patients with and without prior history of depression. Symptoms have ranged from mild to severe and have included suicidal ideation and suicide.
Metoclopramide should be given to patients with a prior history of depression only if the expected benefits outweigh the potential risks.Extrapyramidal symptoms, manifested primarily as acute dystonic reactions, occur in approximately 1 in 500 patients treated with the usual adult dosages of 30?40 mg/day of metoclopramide.
These usually are seen during the first 24?48 hours of treatment with metoclopramide, occur more frequently in pediatric patients and adult patients less than 30 years of age and are even more frequent at the higher doses used in prophylaxis of vomiting due to cancer chemotherapy.
These symptoms may include involuntary movements of limbs and facial grimacing, torticollis, oculogyric crisis, rhythmic protrusion of tongue, bulbar type of speech, trismus, or dystonic reactions resembling tetanus.
Rarely, dystonic reactions may present as stridor and dyspnea, possibly due to laryngospasm.
If these symptoms should occur, inject 50 mg Benadryl®(diphenhydramine hydrochloride) intramuscularly, and they usually will subside. Cogentin®(benztropine mesylate), 1 to 2 mg intramuscularly, may also be used to reverse these reactions.Parkinsonian-like symptoms have occurred, more commonly within the first 6 months after beginning treatment with metoclopramide, but occasionally after longer periods.
These symptoms generally subside within 2?3 months following discontinuance of metoclopramide.Patients with preexisting Parkinson’s disease should be given metoclopramide cautiously, if at all, since such patients may experience exacerbation of parkinsonian symptoms when taking metoclopramide.