Reglan (metoclopramide) is a commonly used medication for the treatment of nausea and vomiting. It has a complex mechanism of action but is known to improve the function of the GI tract, and hasten the speed at which contents move through it. It is also effective for treatment of nausea, especially chemotherapy induced nausea. It is thought to work via blocking of dopaminergic receptors (specifically the D2 receptor). Metoclopramide is also thought to have a weak ability to block serotonin type 3 receptors. (i.e. 5-HT3)
Reglan (metoclopramide) has been associated with causing a serious, and potentially irreversible side effect known as tardive dyskinesia. In fact, the prescribing information for Reglan (metoclopramide) carries the following Black Box Warning:
Tardive dyskinesia is a disorder that is characterized by repetitive and involuntary movements which commonly occur in the facial area (e.g. lip smacking, facial grimaces, rapid eye movements, pursing of lips, rapid blinking etc...)
"WARNING: TARDIVE DYSKINESIA Treatment with metoclopramide can cause tardive dyskinesia, a serious movement disorder that is often irreversible. The risk of developing tardive dyskinesia increases with duration of treatment and total cumulative dose. Metoclopramide therapy should be discontinued in patients who develop signs or symptoms of tardive dyskinesia. There is no known treatment for tardive dyskinesia. In some patients, symptoms may lessen or resolve after metoclopramide treatment is stopped. Treatment with metoclopramide for longer than 12 weeks should be avoided in all but rare cases where therapeutic benefit is thought to outweigh the risk of developing tardive dyskinesia."
The risk of developing tardive dyskinesia while taking Reglan (metoclopramide) is thought to increase the longer you take the medication, which is why the Black Box Warning states it should not be taken longer than 12 weeks. However, short term use of Reglan (metoclopramide) has been associated with tardive dyskinesia as well. Other risk factors include:
- Pediatric patients
- Geriatric patients
- Decreased renal function
While the exact mechanism behind metoclopramide causing tardive dyskinesia is unknown, it appears to be related to drug induced hypersensitivity of dopamine receptors following long term use of dopamine receptor blocking agents, such as Reglan (metoclopramide).
It is very important to identify signs and symptoms of tardive dyskinesia as soon as possible. Identifying, and receiving treatment for symptoms can have a significant impact on remission rates. In addition, while tardive dyskinesia is often irreversible with no known cure, there are some medications that may reduce or eliminate symptoms including:
- Ingrezza (Valbenazine)
- Xenazine (Tetrabenazine)
- Ginkgo biloba
While the likelihood of of tardive dyskinesia is thought to increase with prolonged therapy, there isn't much, if any, data regarding whether or not tardive dyskinesia can occur often drug discontinuation. However, initial symptoms of tardive dyskinesia are very often mild and subtle, which could be easily overlooked. In addition, Reglan (metoclopramide) may actually mask symptoms of tardive dyskinesia. Therefore, upon drug discontinuation, symptoms could be more pronounced.
As mentioned above, if you are experiencing any sort of symptom that is associated with tardive dyskinesia (e.g. involuntary movements), be sure to see your doctor immediately so you may be evaluated.