What is Trimethobenzamide Used For? A Guide to Its Anti-Nausea Effects

October 8, 2025 •

3 min read

Trimethobenzamide is an antiemetic medication used to prevent nausea and vomiting, with an average rating of 8.9 out of 10 from reviewers on Drugs.com. This guide will detail what is Trimethobenzamide used for, covering its applications, mechanism of action, and important safety considerations.

Quick Summary

Trimethobenzamide is an antiemetic medication primarily used to manage nausea and vomiting following surgery or due to gastroenteritis. It works by blocking signals in the brain's chemoreceptor trigger zone and is available in oral capsules and injections. Potential side effects include drowsiness, headache, and dizziness.

Key Points

Used for specific types of nausea: Trimethobenzamide is primarily prescribed to treat nausea and vomiting after surgery and from viral gastroenteritis (stomach flu).
Works in the brain's vomiting center: The medication acts on the chemoreceptor trigger zone (CTZ) in the brainstem, interrupting signals that trigger nausea.
Available in capsule and injection forms: It is available as oral capsules for general use and as an intramuscular injection administered by a healthcare professional.
Carries a risk of drowsiness and dizziness: A common side effect is sedation, and patients are advised to avoid driving or operating machinery until they understand how the medication affects them.
Requires careful use in specific populations: Special precautions are necessary for elderly patients and individuals with pre-existing conditions like Reye's syndrome or liver disease.
Avoid alcohol during treatment: Combining trimethobenzamide with alcohol can worsen side effects and lead to dangerous central nervous system depression.
Not recommended for children in some forms: The injectable and suppository forms are typically contraindicated for use in children due to serious side effect risks.

How Trimethobenzamide Works to Combat Nausea

Trimethobenzamide is an antiemetic medication that helps prevent nausea and vomiting. It is believed to work by affecting the chemoreceptor trigger zone (CTZ) in the brain, which is a region sensitive to chemicals that can induce vomiting. By influencing the CTZ, trimethobenzamide can block signals that would otherwise trigger the vomiting reflex.

Primary Clinical Uses for Trimethobenzamide

Trimethobenzamide is a prescription drug approved for specific uses. Its main applications include managing nausea and vomiting after surgery (postoperative nausea and vomiting, or PONV), where the injectable form is often used in clinical settings, and treating the nausea and vomiting associated with viral gastroenteritis. The oral capsules are also used for these conditions, sometimes following initial treatment with the injection. The medication can help prevent dehydration caused by vomiting. It's important to note that trimethobenzamide suppositories are no longer available in the U.S. and it is generally not recommended for children due to safety concerns.

Dosage and Administration

Dosage and administration of trimethobenzamide vary depending on the form and individual needs. Always adhere to your doctor's instructions.

Oral Capsules (Adults):

Typically 300 mg taken orally, three to four times daily as needed.
Your healthcare provider may adjust the dosage.

Intramuscular (IM) Injection (Adults):

Usually 200 mg injected into a muscle, three to four times daily as needed.
This form is administered by a healthcare professional.
The injection is strictly for intramuscular use.

Side Effects and Precautions

Trimethobenzamide can cause side effects, most of which are mild. However, some can be serious and require medical attention.

Common Side Effects: Drowsiness, dizziness, headache, diarrhea, blurred vision, and muscle cramps are among the more frequent side effects.

Serious Side Effects: Rare but serious side effects can include involuntary muscle movements (extrapyramidal symptoms), changes in mood or depression, seizures, liver problems (jaundice, dark urine), and allergic reactions.

Precautions: Avoid alcohol while taking this medication as it can enhance sedative effects. Be cautious when driving or operating machinery due to potential drowsiness or dizziness. Inform your doctor about any pre-existing conditions like Reye's syndrome or liver disease. Consult a healthcare professional regarding use during pregnancy or breastfeeding, as safety is not fully established. Pediatric use is generally restricted, especially for injectable and suppository forms.

Trimethobenzamide vs. Other Antiemetics

Trimethobenzamide is one option among several antiemetic medications. Here's a comparison with Ondansetron (Zofran):


Feature	Trimethobenzamide (Tigan)	Ondansetron (Zofran)
Mechanism of Action	Blocks the chemoreceptor trigger zone (CTZ).	Blocks serotonin receptors (5-HT3).
Primary Uses	Nausea/vomiting post-surgery or from gastroenteritis.	Nausea/vomiting from chemotherapy, radiation, and surgery.
Common Side Effects	Drowsiness, headache, dizziness, diarrhea.	Headache, fatigue, constipation.
Dosage Forms	Oral capsule, intramuscular injection.	Oral tablets, oral solution, injections.
Frequency	Typically 3 to 4 times a day.	Every 8 to 12 hours.
Key Difference	More sedative potential and distinct mechanism of action.	Less sedating and different primary mechanism.

Conclusion

Trimethobenzamide is a prescription antiemetic primarily used to manage nausea and vomiting following surgery and due to gastroenteritis. It works by affecting the chemoreceptor trigger zone in the brain, helping to control symptoms and prevent dehydration. While generally safe, potential side effects like drowsiness and dizziness should be noted, and precautions should be followed. Consulting a healthcare professional is crucial to determine if trimethobenzamide is appropriate, especially for older patients or those with underlying conditions.

For further information on antiemetics, refer to resources like the National Center for Biotechnology Information (NCBI) Bookshelf.

Frequently Asked Questions

Yes, Tigan is a brand name for the medication trimethobenzamide. While the brand-name capsules are no longer produced, the medication is still available as generic oral capsules and a brand-only intramuscular injection.

The usual adult dose for oral capsules is 300 mg, taken three or four times a day as needed. The dosage may be adjusted by a doctor based on your specific condition and response to treatment.

Trimethobenzamide is most effective for nausea and vomiting caused by specific issues like surgery or gastroenteritis. For other types of nausea, such as motion sickness or morning sickness, different medications or approaches may be more appropriate.

If you miss a dose, take it as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not take a double dose.

Yes, trimethobenzamide can interact with other central nervous system depressants, such as alcohol, opioids, and sedatives. It is essential to inform your doctor about all prescription and over-the-counter medications, supplements, and herbal products you are taking.

In 2007, the FDA removed trimethobenzamide suppositories from the market in the United States because they were not proven to be effective for treating nausea and vomiting. Only the oral capsules and injectable forms are currently available.

The use of trimethobenzamide, especially the injectable form, is generally not recommended for children due to the risk of serious side effects. For children, the use and dosage must be determined by a healthcare provider.

The safety of trimethobenzamide during pregnancy is not fully established. While some animal studies show no teratogenic risk, limited data exists on human pregnancy. It is considered a third-line option for pregnant women who have failed other therapies.

The antiemetic effects of trimethobenzamide typically last for approximately 3 to 4 hours after an oral dose. The elimination half-life is between 7 and 9 hours.

Though rare, trimethobenzamide can cause extrapyramidal symptoms, which include involuntary muscle movements, tremors, stiffness, and restlessness. If you notice these side effects, contact your doctor immediately.