Trimethobenzamide (oral)

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# Overview
Trimethobenzamide (oral) is an antiemetic that is FDA approved for the treatment of postoperative nausea and vomiting and for nausea associated with gastroenteritis..   Common adverse reactions include hypotension, diarrhea, xerostomia, and somnolence.

# Adult Indications and Dosage

## FDA-Labeled Indications and Dosage (Adult)
- Trimethobenzamide hydrochloride capsules, USP are indicated for the treatment of postoperative nausea and vomiting and for nausea associated with gastroenteritis.
- Dosage should be adjusted according to the indication for therapy, severity of symptoms and the response of the patient.
- Dose adjustment such as reducing the total dose administered at each dosing or increasing the dosing interval should be considered in elderly patients with renal impairment (creatinine clearance 70 mL/min/1.73m2). Final dose adjustment should be based upon integration of clinical efficacy and safety considerations.
- In subjects with renal impairment (creatinine clearance 70 mL/min/1.73m2), dose adjustment such as reducing the total dose administered at each dosing or increasing the dosing interval should be considered.

## Off-Label Use and Dosage (Adult)

### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Trimethobenzamide (oral) in adult patients.

### NonGuideline-Supported Use
There is limited information regarding Off-Label NonGuideline-Supported Use of Trimethobenzamide (oral) in adult patients.

# Pediatric Indications and Dosage

## FDA-Labeled Indications and Dosage (Pediatric)
There is limited information regarding FDA-Labeled Use of Trimethobenzamide (oral) in pediatric patients.

## Off-Label Use and Dosage (Pediatric)

### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Trimethobenzamide (oral) in pediatric patients.

### NonGuideline-Supported Use
There is limited information regarding Off-Label NonGuideline-Supported Use of Trimethobenzamide (oral) in pediatric patients.

# Contraindications
- Use of any dosage form in patients with known hypersensitivity to trimethobenzamide is contraindicated.

# Warnings
- Caution should be exercised when administering trimethobenzamide hydrochloride capsules, USP to children for the treatment of vomiting. Antiemetics are not recommended for treatment of uncomplicated vomiting in children and their use should be limited to prolonged vomiting of known etiology. There are two principal reasons for caution
- The extrapyramidal symptoms which can occur secondary to trimethobenzamide hydrochloride capsules, USP may be confused with the central nervous system signs of an undiagnosed primary disease responsible for the vomiting, e.g., Reye's syndrome or other encephalopathy.
- It has been suspected that drugs with hepatotoxic potential, such as trimethobenzamide hydrochloride capsules, USP, may unfavorably alter the course of Reye's syndrome. Such drugs should therefore be avoided in children whose signs and symptoms (vomiting) could represent Reye's syndrome.
- Trimethobenzamide hydrochloride capsules, USP may produce drowsiness. Patients should not operate motor vehicles or other dangerous machinery until their individual responses have been determined.
- During the course of acute febrile illness, encephalitides, gastroenteritis, dehydration and electrolyte imbalance, especially in children and the elderly or debilitated, CNS reactions such as opisthotonos, convulsions, coma and extrapyramidal symptoms have been reported with and without use of trimethobenzamide hydrochloride capsules, USP or other antiemetic agents. In such disorders caution should be exercised in administering trimethobenzamide hydrochloride capsules, USP, particularly to patients who have recently received other CNS-acting agents (phenothiazines, barbiturates, belladonna derivatives). Primary emphasis should be directed toward the restoration of body fluids and electrolyte balance, the relief of fever and relief of the causative disease process. Overhydration should be avoided since it may result in cerebral edema.
- The antiemetic effects of trimethobenzamide hydrochloride capsules, USP may render diagnosis more difficult in such conditions as appendicitis and obscure signs of toxicity due to overdosage of other drugs.
- Adjustment of Dose in Renal Failure
- A substantial route of elimination of unchanged trimethobenzamide is via the kidney. Dosage adjustment should be considered in patients with reduced renal function including some elderly patients

# Adverse Reactions

## Clinical Trials Experience
There is limited information regarding Clinical Trial Experience of Trimethobenzamide (oral) in the drug label.

## Postmarketing Experience
There is limited information regarding Postmarketing Experience of Trimethobenzamide (oral) in the drug label.

# Drug Interactions
There is limited information regarding Trimethobenzamide (oral) Drug Interactions in the drug label.

# Use in Specific Populations

### Pregnancy
Pregnancy Category (FDA):
- Trimethobenzamide hydrochloride was studied in reproduction experiments in rats and rabbits and no teratogenicity was suggested. The only effects observed were an increased percentage of embryonic resorptions or stillborn pups in rats administered 20 mg and 100 mg/kg and increased resorptions in rabbits receiving 100 mg/kg. In each study these adverse effects were attributed to one or two dams. The relevance to humans is not known. Since there is no adequate experience in pregnant or lactating women who have received this drug, safety in pregnancy or in nursing mothers has not been established.
Pregnancy Category (AUS): 
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Trimethobenzamide (oral) in women who are pregnant.

### Labor and Delivery
There is no FDA guidance on use of Trimethobenzamide (oral) during labor and delivery.

### Nursing Mothers
There is no FDA guidance on the use of Trimethobenzamide (oral) with respect to nursing mothers.

### Pediatric Use
There is no FDA guidance on the use of Trimethobenzamide (oral) with respect to pediatric patients.

### Geriatic Use
- The clearance of trimethobenzamide is not known in patients with renal impairment. However, it may be advisable to consider reduction in the dosing of trimethobenzamide in elderly patients with renal impairment considering that a substantial amount of excretion and elimination of trimethobenzamide occurs via the kidney and that elderly patients may have various degrees of renal impairment.
- Clinical studies of trimethobenzamide hydrochloride did not include sufficient numbers of patients aged 65 and over to determine whether they respond differently from younger patients. Although there are studies reported in the literature that included elderly patients >65 years old with younger patients, it is not known if there are differences in efficacy or safety parameters for elderly and non-elderly patients treated with trimethobenzamide. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
- This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

### Gender
- Systemic exposure to trimethobenzamide was similar between men (N=40) and women (N=28).

### Race
- Pharmacokinetics appeared to be similar for Caucasians (N=53) and African Americans (N=12).

### Renal Impairment
- The clearance of trimethobenzamide is not known in patients with renal impairment. However, it may be advisable to consider reduction in the dosing of trimethobenzamide in patients with renal impairment considering that a substantial amount of excretion and elimination of trimethobenzamide occurs via the kidney.

### Hepatic Impairment
There is no FDA guidance on the use of Trimethobenzamide (oral) in patients with hepatic impairment.

### Females of Reproductive Potential and Males
There is no FDA guidance on the use of Trimethobenzamide (oral) in women of reproductive potentials and males.

### Immunocompromised Patients
There is no FDA guidance one the use of Trimethobenzamide (oral) in patients who are immunocompromised.

# Administration and Monitoring

### Administration
- Intramuscular

### Monitoring
There is limited information regarding Monitoring of Trimethobenzamide (oral) in the drug label.

# IV Compatibility
There is limited information regarding IV Compatibility of Trimethobenzamide (oral) in the drug label.

# Overdosage
There is limited information regarding Chronic Overdose of Trimethobenzamide (oral) in the drug label.

# Pharmacology

## Mechanism of Action
- The mechanism of action of trimethobenzamide hydrochloride capsules, USP as determined in animals is obscure, but may involve the chemoreceptor trigger zone (CTZ), an area in the medulla oblongata through which emetic impulses are conveyed to the vomiting center; direct impulses to the vomiting center apparently are not similarly inhibited. In dogs pretreated with trimethobenzamide HCl, the emetic response to apomorphine is inhibited, while little or no protection is afforded against emesis induced by intragastric copper sulfate.

## Structure
- Chemically, trimethobenzamide HCl is N-benzyl]-3,4,5-trimethoxybenzamide monohydrochloride. It has a molecular weight of 424.93 and the following structural formula:
- Each capsule for oral use contains trimethobenzamide hydrochloride equivalent to 300 mg.
- Inactive Ingredients: FDA/E172 Red Iron Oxide, gelatin, magnesium stearate, microcrystalline cellulose, sodium starch glycolate and titanium dioxide. The imprinting ink contains D&C *Yellow #10 Lake, FD&C Blue #1, FD&C Blue #2, FD&C Red #40, Iron Oxide Black, propylene glycol and shellac glaze.

## Pharmacodynamics
There is limited information regarding Pharmacodynamics of Trimethobenzamide (oral) in the drug label.

## Pharmacokinetics
- The pharmacokinetics of trimethobenzamide have been studied in healthy adult subjects. Following administration of 200 mg (100 mg/mL) trimethobenzamide hydrochloride I.M. injection, the time to reach maximum plasma concentration (Tmax) was about half an hour, about 15 minutes longer for trimethobenzamide hydrochloride 300 mg oral capsule than an I.M. injection. A single dose of trimethobenzamide hydrochloride 300 mg oral capsule provided a plasma concentration profile of trimethobenzamide similar to trimethobenzamide hydrochloride 200 mg I.M. The relative bioavailability of the capsule formulation compared to the solution is 100%. The mean elimination half-life of trimethobenzamide is 7 to 9 hours. Between 30  50% of a single dose in humans is excreted unchanged in the urine within 4872 hours. The major pathway of trimethobenzamide metabolism is through oxidation resulting in the formation of trimethobenzamide N-oxide metabolite. The pharmacologic activity of this major metabolite has not been evaluated.

## Nonclinical Toxicology
There is limited information regarding Nonclinical Toxicology of Trimethobenzamide (oral) in the drug label.

# Clinical Studies
There is limited information regarding Clinical Studies of Trimethobenzamide (oral) in the drug label.

# How Supplied
There is limited information regarding Trimethobenzamide (oral) How Supplied in the drug label.

## Storage
There is limited information regarding Trimethobenzamide (oral) Storage in the drug label.

# Images

## Drug Images

## Package and Label Display Panel

# Patient Counseling Information
There is limited information regarding Patient Counseling Information of Trimethobenzamide (oral) in the drug label.

# Precautions with Alcohol
- Concomitant use of alcohol with trimethobenzamide hydrochloride capsules, USP may result in an adverse drug interaction.

# Brand Names
- Benzacot
- Tigan
- Tebamide
- Arrestin
- Stemetic
- Ticon
- Tribenzagan

# Look-Alike Drug Names
There is limited information regarding Trimethobenzamide (oral) Look-Alike Drug Names in the drug label.

# Drug Shortage Status

# Price