trimethobenzamide

Action and Spectrum

Adult: 

Dosage forms & Strengths 

Capsules 

300 mg 

Injectable solution 

100mg/ml 

Emesis 

Take a dose of 300 mg orally every 6 to 8 hours 

Dosing consideration 

Renal Impairment 

CrCl ≤70 mL/min/1.73 m2: 

Adjust the dosage as needed based on the patient’s reaction; closely monitor renal function; decrease the dose or increase the time between doses 

Pediatric: 

Dosage forms & Strengths 

Capsules 

300 mg 

Emesis 

Take a daily dose of 20 mg/kg orally in divided doses every 6 to 8 hours 

Drug Interaction

Adverse Reaction

Frequency not defined 

Irritation at the injection site 

Symptoms of Parkinson’s 

Sedation 

Headache 

Hypersensitivity reactions 

Dizziness 

Black Box Warning

None 

Contraindication / Caution

Contraindication/Caution: 

trimethobenzamide is generally considered safe and well-tolerated when used as directed. However, there are certain contraindications and cautions associated with its use. These include: 

• Hypersensitivity: trimethobenzamide should not be used in individuals who have a known hypersensitivity to the medication or any of its components. 
• Severe hepatic impairment: trimethobenzamide should be used with caution in individuals with severe hepatic impairment, as the medication is metabolized by the liver. 
• CNS depression: trimethobenzamide may cause central nervous system (CNS) depression, especially in high doses. Therefore, it should be used with caution in individuals with a history of CNS depression, such as those with alcoholism, depression, or other psychiatric disorders. 
• Elderly: trimethobenzamide should be used with caution in elderly individuals, as they may be more sensitive to the side effects of the medication. 
• Pregnancy and breastfeeding: The safety of trimethobenzamide during pregnancy and breastfeeding is not well-established. Therefore, it should only be used in pregnant or breastfeeding women if the potential benefits outweigh the potential risks. 

Pregnancy / Lactation

Pregnancy consideration:  

No data is available for the use of tecovirimat in pregnant women. 

Breastfeeding warnings:  

Consider the mother’s need for the drug and their potential side effects  

Pregnancy category: 

• Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first or later trimester. 
• Category B: There is no affirmation of risk to the fetus found in animal reproduction studies, and there are not enough studies on pregnant women. 
• Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for a product in humans; Pregnant women must take care of the potential risks. 
• Category D: There is adequate data available with sufficient evidence of human fetal risk from various platforms. However, despite potential dangers may be used only in emergency cases for potential benefits. 
• Category X: Drugs listed in this category outweigh risks over benefits. The drug is not for pregnant women. 
• Category N: No data is available for the drug under this category. 

Pharmacology

Pharmacology: 

trimethobenzamide is an antiemetic medication that works by blocking dopamine receptors in the chemoreceptor trigger zone (CTZ) of the brain. The CTZ is an area of the brain that receives input from the gastrointestinal tract and is responsible for initiating the vomiting reflex in response to certain stimuli. 

By blocking dopamine receptors in the CTZ, trimethobenzamide prevents the activation of the vomiting center in the brain, which in turn reduces the sensation of nausea and the urge to vomit. trimethobenzamide also has some weak anticholinergic activity, which may contribute to its antiemetic effects. 

trimethobenzamide is rapidly absorbed after oral administration and reaches peak plasma concentrations within 1 to 2 hours. It is extensively metabolized in the liver, and its metabolites are excreted in the urine. The half-life of trimethobenzamide is approximately 6 hours. 

Pharmacodynamics: 

The pharmacodynamics of trimethobenzamide are primarily related to its antiemetic effects. Trimethobenzamide works by blocking dopamine receptors in the chemoreceptor trigger zone (CTZ) of the brain, which reduces the sensation of nausea and the urge to vomit. 

The CTZ is a part of the brain that receives input from the gastrointestinal tract and is responsible for initiating the vomiting reflex in response to certain stimuli. By blocking dopamine receptors in the CTZ, trimethobenzamide prevents the activation of the vomiting center in the brain, which in turn reduces the sensation of nausea and the urge to vomit. 

In addition to its effects on dopamine receptors, trimethobenzamide also has some weak anticholinergic activity, which may contribute to its antiemetic effects. 

Pharmacokinetics: 

Absorption 

Onset of action is 15-35 min (intramuscular),  

10-40 min (oral) 

Duration of action is 2-3 hours (intramuscular), 3-4 hours (oral) 

Distribution 

The bioavailability of oral dose equals 60-100% of intramuscular dose 

The half-life of elimination is 7-9 hours 

Metabolism 

The drug is metabolized in liver 

Metabolites formed are N-desmethyl & N-oxide derivatives 

Elimination and Excretion 

The drug is excreted in (30-50%) in urine and in feces via bile 

Adminstartion

Administration: 

trimethobenzamide is typically administered orally in the form of capsules or tablets. The usual adult dose for the treatment of nausea and vomiting is 300 mg to 400 mg taken three to four times a day, with a maximum daily dose of 1200 mg. 

The drug should be taken with food to minimize gastrointestinal side effects such as stomach upset. If the drug is being used to prevent motion sickness, it should be taken 30 minutes to 1 hour before travel. 

Intramuscular or intravenous formulations of trimethobenzamide are also available, but these are typically used only in hospitalized patients who are unable to take the drug orally. 

The duration of treatment with trimethobenzamide will depend on the underlying condition causing the nausea and vomiting. In general, the drug should be used for the shortest duration possible to control symptoms. If symptoms persist, patients should be re-evaluated to determine the underlying cause of the nausea and vomiting. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: trimethobenzamide 

Pronounced: Tri-​metho-​ben-​za-​mide  

Why do we use trimethobenzamide? 

trimethobenzamide is primarily used as an antiemetic medication to treat nausea and vomiting caused by various conditions, including: 

• Gastrointestinal disorders: trimethobenzamide can be used to treat nausea and vomiting caused by gastroenteritis, gastritis, and other gastrointestinal disorders. 
• Motion sickness: trimethobenzamide is effective in preventing motion sickness and can be taken prior to traveling to prevent symptoms. 
• Chemotherapy-induced nausea and vomiting: trimethobenzamide is used in combination with other antiemetic medications to prevent nausea and vomiting caused by chemotherapy. 
• Postoperative nausea and vomiting: trimethobenzamide can be used to prevent and treat nausea and vomiting after surgery.