Description
Metoclopramide Pharmacodynamics
Specific blocker of dopamine (D2) and serotonin (5-NT3) receptors, inhibits chemoreceptors of brainstem trigger zone, impairs sensitivity of visceral nerves transmitting impulses from pylorus and duodenum to vomiting center. Through hypothalamus and parasympathetic nervous system (innervation of the gastrointestinal tract) it has a regulatory and coordinating effect on tone and motor activity of the upper gastrointestinal tract (including tone of the lower digestive sphincter at rest). Increases the tone of the stomach and intestines, accelerates gastric emptying, reduces hyperacidic stasis, prevents pyloric and esophageal reflux, stimulates intestinal peristalsis. It normalizes bile secretion, decreases spasm of sphincter of Oddi without changing its tone, eliminates gall bladder dyskinesia. It does not affect blood vessel tone of the brain, blood pressure (BP), respiratory function, as well as kidney and liver, hematopoiesis, gastric and pancreatic secretion. Like other dopamine receptor blockers, it stimulates prolactin secretion, increases tissue sensitivity to acetylcholine (action does not depend on vagus innervation, but is eliminated by choline blockers), stimulating aldosterone secretion (fluid retention is possible).
Indications
Vomiting, nausea (in anesthesia, radiation therapy, liver and kidney disease, cranial trauma, migraine), Tourette’s syndrome (generalized tics and vocalizations in children), Correction of side effects of drugs (digitalis, cytostatics, antibiotics, morphine), vomiting of pregnant women (II-III trimester), hiccups of different genesis, atony and hypotony of stomach and duodenum (including post-operative and post-surgical phases against the background of the syndrome of the stomach and duodenum), erythrocytes. including postoperative, against diabetic neuropathy), reflux esophagitis, biliary dyskinesia, flatulence.
It is also used as part of the complex treatment of gastric and duodenal ulcers, for acceleration of peristalsis during GI X-ray examinations.
Contraindications
Hypersensitivity to metoclopramide or drug components, gastrointestinal bleeding, intestinal obstruction, gastric pylorus stenosis, gastrointestinal perforation (including conditions when intensification of gastrointestinal motility is undesirable; pheochromocytoma (hypertensive crisis is possible, due to catecholamine release from the tumor), epilepsy, glaucoma, extrapyramidal disorders, Parkinson’s disease, prolactin dependent tumors, vomiting during treatment or overdose of neuroleptics. Vomiting in patients with breast cancer.
Caution:
Renal/hepatic failure, bronchial asthma, arterial hypertension, advanced age, early childhood (under 2 years) (increased risk of dyskinetic syndrome).
Pregnancy and lactation:
The drug is contraindicated in the first trimester of pregnancy. In II and III trimesters the drug is used only in cases of extreme necessity when the potential benefit for a mother exceeds the possible risk for a fetus. If necessary, the breast-feeding should be stopped for the duration of treatment because the drug is excreted with the breast milk.
Directions for use and dosages
- Adults in case of vomiting, severe nausea – intramuscularly or intravenously, 10 mg (2 ml of 5 mg/ml solution) 1-3 times a day. The maximum single dose is 20 mg, the maximum daily dose is 60 mg (for all routes of administration).
- Before radiological examination in adults, 10-20 mg intravenously (5-15 min before the examination).
- Patients with clinically manifested hepatic and renal insufficiency receive half the usual dose at the beginning of treatment; the subsequent dose depends on individual patient’s reaction to metoclopramide.
- For prevention and treatment of nausea and vomiting caused by cytostatics and radiotherapy, the drug is administered intravenously in dose of 2 mg/kg 30 min before cytostatics or radiotherapy; if necessary, the drug is repeated in 2-3 hours.
- Children over 6 years of age take 5 mg 1 to 3 times a day.
- In children under 6 years of age, the daily dose is 0.5-1 mg/kg, and the frequency of administration is 1-3 times a day.
