Brands, Medical Use, Clinical Data
Drug Category
- Antiemetics
- Prokinetic Agents
- Dopamine Antagonists
Dosage Forms
Brands / Synonyms
Apo-Metoclop; Cerucal; Clopra; Clopra-Yellow; Clopromate; DEL; Duraclamid; Elieten; Emetid; Emperal; Eucil; Gastrese; Gastro-Timelets; Gastrobid; Gastromax; Gastronerton; Gastrosil; Gastrotablinen; Gastrotem; Imperan; Maxeran; Maxolon; Meclopran; Metaclopramide; Metaclopromide; Metamide; Methochlopramide; Methoclopramide; Metochlopramide; Metoclol; Metoclopramida [Inn-Spanish]; Metoclopramide; Metoclopramide Hcl; Metoclopramide Hydrochloride; Metoclopramide Intensol; Metoclopramide Omega; Metoclopramidum [Inn-Latin]; Metocobil; Metramid; Moriperan; Mygdalon; Neu-Sensamide; Nu-Metoclopramide; Octamide; Parmid; Paspertin; Peraprin; Plasil; Pms-Metoclopramide; Pramiel; Pramin; Primperan; Reclomide; Reglan; Reliveran; Terperan
Indications
For the treatment of gastroesophageal reflux disease (GERD)
Pharmacology
Metoclopramide, although chemically related to procainamide, does not possess local anesthetic or antiarrhythmic properties. Metoclopramide is used to enhance GI motility, to treat diabetic gastroparesis, as an antinauseant, and to facilitate intubation of the small bowel during radiologic examination. Metoclopramide may be used to treat chemotherapy-induced emesis and as a radiosensitizing agents in the treatment of non-small cell lung carcinoma and glioblastomas in the future.
Mechanism of Action
Metoclopramide inhibits gastric smooth muscle relaxation produced by dopamine, therefore increasing cholinergic response of the gastrointestinal smooth muscle. It accelerates intestinal transit and gastric emptying by preventing relaxation of gastric body and increasing the phasic activity of antrum. Simultaneously, this action is accompanied by relaxation of the upper small intestine, resulting in an improved coordination between the body and antrum of the stomach and the upper small intestine. Metoclopramide also decreases reflux into the esophagus by increasing the resting pressure of the lower esophageal sphincter and improves acid clearance from the esophagus by increasing amplitude of esophageal peristaltic contractions. Metoclopramide's dopamine antagonist action raises the threshold of activity in the chemoreceptor trigger zone and decreases the input from afferent visceral nerves. Studies have also shown that high doses of metoclopramide can antagonize 5-hydroxytryptamine (5-HT) receptors in the peripheral nervous system in animals.
Absorption
Rapidly and well absorbed (oral bioavailability 80±15.5%).
Toxicity
Oral, mouse LD50: 280 mg/kg. Signs of overdose include drowsiness, disorientation, and extrapyramidal reactions.
Biotrnasformation / Drug Metabolism
Hepatic
Contraindications
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 pheochro-mocytoma because the drug may cause a
hypertensive crisis, probably due to release of catecholamines from the tumor. Such hypertensive crises may be
controlled by phen-tolamine.
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.
Drug Interactions
DRUG INTERACTIONS
The effects of metoclopramide on gastrointestinal motility are antagonized by anticholinergic
drugs and narcotic analgesics. Additive sedative effects can occur when metoclopramide is given
with alcohol, sedatives, hypnotics, narcotics, or tranquilizers.
The finding that metoclopramide releases catecholamines in patients with essential hypertension
suggests that it should be used cautiously, if at all, in patients receiving monoamine oxi-dase
inhibitors.
Absorption of drugs from the stomach may be diminished (e.g., digoxin) by metoclopramide, whereas
the rate and/or extent of absorption of drugs from the small bowel may be increased (e.g.,
acetaminophen, tetracycline, levodopa, ethanol, cyclosporine).
Gastroparesis (gastric stasis) may be responsible for poor diabetic control in some patients.
Exogenously administered insulin may begin to act before food has left the stomach and lead to
hypoglycemia. Because the action of metoclopramide will influence the delivery of food to the
intestines and thus the rate of absorption, insulin dosage or timing of dosage may require adjustment.
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