Trimethobenzamide
Encyclopedia
Trimethobenzamide is an antiemetic
used to prevent nausea
and vomiting
. It is often prescribed for patients with gastroenteritis
, medication-induced nausea, and other illnesses. Trimethobenzamide is generally considered the most potent antiemetic that does not have effects on the serotonergic, dopaminergic, or histaminergic systems, so it has a lower likelihood of causing undesired side effects. In the United States, it requires a prescription.
(CTZ) of the medulla oblongata
.
, and jaundice
.
and King Pharmaceuticals
, respectively. It is available as oral capsules and injectable formulations.
Trimethobenzamide was also available as a rectal suppository
, but such formulations were banned by the U.S. Food and Drug Administration
on April 6, 2007 due to unproven efficacy.
Antiemetic
An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of opioid analgesics, general anaesthetics, and chemotherapy directed against cancer....
used to prevent nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...
and vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
. It is often prescribed for patients with gastroenteritis
Gastroenteritis
Gastroenteritis is marked by severe inflammation of the gastrointestinal tract involving both the stomach and small intestine resulting in acute diarrhea and vomiting. It can be transferred by contact with contaminated food and water...
, medication-induced nausea, and other illnesses. Trimethobenzamide is generally considered the most potent antiemetic that does not have effects on the serotonergic, dopaminergic, or histaminergic systems, so it has a lower likelihood of causing undesired side effects. In the United States, it requires a prescription.
Mechanism of action
Although the specific mechanism through which trimethobenzamide functions is unknown, it is believed to affect the chemoreceptor trigger zoneChemoreceptor trigger zone
The chemoreceptor trigger zone , is an area of the medulla that receives inputs from blood-borne drugs or hormones, and communicates with the vomiting center, to initiate vomiting. The CTZ is close to the area postrema on the floor of the fourth ventricle and is outside of the blood-brain barrier...
(CTZ) of the medulla oblongata
Medulla oblongata
The medulla oblongata is the lower half of the brainstem. In discussions of neurology and similar contexts where no ambiguity will result, it is often referred to as simply the medulla...
.
Side effects
Possible side effects include drowsiness, dizziness, headache, diarrhea, muscle cramps, and blurred vision. More serious adverse effects include skin rash, tremors, parkinsonismParkinsonism
Parkinsonism is a neurological syndrome characterized by tremor, hypokinesia, rigidity, and postural instability. The underlying causes of parkinsonism are numerous, and diagnosis can be complex...
, and jaundice
Jaundice
Jaundice is a yellowish pigmentation of the skin, the conjunctival membranes over the sclerae , and other mucous membranes caused by hyperbilirubinemia . This hyperbilirubinemia subsequently causes increased levels of bilirubin in the extracellular fluid...
.
Formulations
Trimethobenzamide is marketed under the brand names Tebamide and Tigan, manufactured by GlaxoSmithKlineGlaxoSmithKline
GlaxoSmithKline plc is a global pharmaceutical, biologics, vaccines and consumer healthcare company headquartered in London, United Kingdom...
and King Pharmaceuticals
King Pharmaceuticals
King Pharmaceuticals , was the world's 39th largest pharmaceutical company, based in Bristol, Tennessee. However, on October 12, 2010, King was acquired by Pfizer for $14.25 per share. King produced a wide range of pharmaceuticals, including Altace for heart attack prevention, Levoxyl for...
, respectively. It is available as oral capsules and injectable formulations.
Trimethobenzamide was also available as a rectal suppository
Suppository
A suppository is a drug delivery system that is inserted into the rectum , vagina or urethra , where it dissolves.They are used to deliver both systemically-acting and locally-acting medications....
, but such formulations were banned by the U.S. Food and Drug Administration
Food and Drug Administration
The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...
on April 6, 2007 due to unproven efficacy.