Metoclopramide (MCP) is a medication that acts on the gastrointestinal tract. Metoclopramide reduces nausea and vomiting and increases stomach activity. It is available in several forms, such as tablets, drops, and suppositories.
What is metoclopramide?
Metoclopramide (MCP) is a medication that affects the gastrointestinal tract. Metoclopramide is a prescription medication primarily for nausea and vomiting. Because of its rare but serious side effects on the musculoskeletal system, use should not exceed 5 days. Metoclopramide should not be used in children younger than 2 years of age, and patients with certain preexisting conditions (especially intestinal obstruction, gastrointestinal bleeding, and epilepsy).
Pharmacologic Action
Metoclopramide belongs to the dopamine antagonists. Dopamine, as an endogenous neurotransmitter, can induce vomiting by binding to its binding sites in the vomiting center in the brainstem. Metoclopramide prevents dopamine from binding to its binding site (receptor). This abolishes dopamine-mediated effects. Receptors for dopamine are located primarily in the brain. Here, dopamine also mediates other processes such as the control of voluntary movements. Some side effects of metoclopramide can be explained by this mechanism of action. Other binding sites for dopamine are found in the gastrointestinal tract, where it helps to slow digestion. In addition, metoclopramide also affects the receptors of serotonin, another neurotransmitter produced by the body. Binding sites for serotonin are also located in the brain, but also in the gastrointestinal tract. Here, metoclopramide increases gastric activity and shortens the passage time of food. In addition, metoclopramide increases the concentration of a certain sex hormone, prolactin. Among other things, this sex hormone regulates milk production in the mammary gland. Metoclopramide is filtered back out of the blood by the kidneys and then excreted in the urine. Therefore, in the case of reduced kidney function (renal insufficiency), attention must be paid to the dosage.
Medical use and application
Metroclopramide is a prescription medication. It is reliably effective against nausea and vomiting. Accordingly, metoclopramide is used for nausea of various causes:
In travel nausea, migraine, drug intolerance, traumatic brain injury and after surgery. However, its effect is limited in nausea caused by chemotherapy and after surgery, which is why other drugs are used here. In addition, metoclopramide is used to improve gastric emptying. Thus, metoclopramide can be used to support the treatment of irritable stomach or heartburn. Furthermore, this effect of metoclopramide is exploited to accelerate the onset of action of other drugs. For this reason, metoclopramide is often a component of migraine medications.
Risks and side effects
Because metoclopramide acts on a multifaceted receptor, its side effects are also multifaceted. Occasionally, metoclopramide causes fatigue and dizziness. Patients sometimes also express headaches and sleep disturbances. Less common, but far more serious, are side effects that affect movement coordination. Patients then suffer from tremors, muscle cramps and involuntary movements. Particularly feared are tardive dyskinesias, movement disorders that occur after long use of certain drugs. Affected persons constantly make chewing movements, involuntarily grimace, and suddenly move their arms and legs violently without meaning to. Tardive dyskinesia is usually irreversible, meaning that it does not subside after the triggering drug is discontinued. For this reason, the EMA, the European Medicines Agency, recommends that the use of metoclopramide be considered even more critically. In addition, applications longer than 5 days should be avoided because of the risk of tardive dyskinesia. Due to increased prolactin levels, milk secretion may occur even in nonpregnant women. Women also frequently complain of menstrual cramps. In men, enlargement of the mammary gland may occur. If side effects occur, a doctor should be consulted immediately. In case of severe side effects, the drug should be discontinued immediately. Metoclopramide may be used in children 2 years of age and older.In pregnancy, the applications are to be considered critically, in lactation not allowed at all. Metoclopramide must not be used in patients with certain pre-existing conditions. These include intestinal obstruction due to intestinal obstruction, bleeding in the gastrointestinal tract (due to gastric ulcers, tumors, or the like ), epilepsy, and depression (when taking medications of a certain group called MAO inhibitors).
