Trimethobenzamide
Trimethobenzamide is an antiemetic (anti-nausea) medication used to treat postoperative nausea and vomiting and nausea associated with gastroenteritis.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 3 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
Trimethobenzamide (Tigan) is an anti-nausea medicine for adults with nausea and vomiting after surgery or from gastroenteritis (a stomach bug). It acts on the brain's vomiting trigger zone and is an older standby, on the market since about 1974, available as a generic and prescribed less often than newer options. Most people tolerate it fairly well, and drowsiness and dizziness are what they notice most. The one thing to watch for is sudden spasms of the head, neck or eyes, or restless, jerky movements, which warrant a prompt call to your prescriber. It is not for children, and people with liver or kidney problems need closer monitoring.
Clinical pearls
- Skip alcohol entirely while taking it, because it adds to this drug's sedation and raises the risk of serious confusion.
- Make sure anyone prescribing an antipsychotic, opioid, sleep aid or anxiety medicine knows you take trimethobenzamide.
- Yellowing of the skin or eyes is a reason to stop it and get checked, since it can harm the liver.
- Hold off on driving until you know how drowsy it makes you, because it can slow reaction time much like alcohol.
Patient information guide A plain-language walkthrough of Trimethobenzamide, written from its FDA label.
What Trimethobenzamide is used for
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Trimethobenzamide is an antiemetic (anti-nausea) medication approved for adults across several products and formulations. Supported uses include:
- Treatment of postoperative nausea and vomiting (nausea and vomiting that occurs after surgery)
- Treatment of nausea associated with gastroenteritis (stomach or intestinal illness)
- The oral capsule (Trimethobenzamide Hydrochloride capsules) is approved for both of these uses in adults only
- Tigan Intramuscular Injection is indicated for both postoperative nausea and vomiting and nausea from gastroenteritis in adults
- Trimethobenzamide Hydrochloride Intramuscular Injection is indicated for both postoperative nausea and vomiting and nausea from gastroenteritis in adults
- None of these products are recommended for children
How Trimethobenzamide works
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Trimethobenzamide is thought to work by acting on the chemoreceptor trigger zone (CTZ) — a part of the brain that receives chemical signals telling the body to vomit. By influencing this zone, the drug helps interrupt the signal chain that leads to nausea and vomiting. However, it does not appear to block vomiting that is triggered by direct irritation of the stomach itself. The exact mechanism has been studied in animals and is not fully understood in humans.
Trimethobenzamide dosage
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The oral capsule form is taken by mouth several times per day. The intramuscular injection forms (Tigan and Trimethobenzamide Hydrochloride Injection) are given as shots into muscle several times per day — never into a vein. There is no specific food restriction mentioned in the labeling. Older adults and people with kidney disease may need to take doses less frequently; your prescriber will tailor the schedule.
- Always follow your prescriber's specific instructions for timing and frequency
- Use the lowest effective dose and adjust based on how well it works and how well you tolerate it
- If you miss a dose, follow your prescriber's guidance — do not double up without being told to
Dosing details from the FDA-approved label
From the Trimethobenzamide prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
- Usual Adult Dosage (injectable, 100 mg/mL; not for use in pediatric patients)
- 2 mL (200 mg) t.i.d. or q.i.d. intramuscularly
- For intramuscular use only; not recommended for intravenous use. Deep injection into the upper outer quadrant of the gluteal region may minimize injection-site effects.
- Adult (capsule)
- 300 mg orally three or four times daily
- Select the lowest effective daily dosage and adjust as needed based upon therapeutic response and tolerability
- Geriatric patients and/or patients with renal impairment (creatinine clearance 70 mL/min/1.73m2 or less)
- Reduce the daily dosage by increasing the dosing interval and adjust as needed based upon therapeutic response and tolerability
- Older labeling states reducing the total dose at each dosing or increasing the dosing interval should be considered
- Monitor renal function
Read the label’s full dosing text
DOSAGE AND ADMINISTRATION (See WARNINGS and PRECAUTIONS .) Dosage should be adjusted according to the indication for therapy, severity of symptoms and the response of the patient. Geriatric Patients 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/1.73m 2 ). Final dose adjustment should be based upon integration of clinical efficacy and safety considerations. (See CLINICAL PHARMACOLOGY and PRECAUTIONS ). Patients with Renal Impairment In subjects with renal impairment (creatinine clearance ≤ 70 mL/min/1.73m 2 ), dose adjustment such as reducing the total dose administered at each dosing or increasing the dosing interval should be considered. (See CLINICAL PHARMACOLOGY and DOSAGE AND ADMINISTRATION ). INJECTABLE, 100 mg/mL (Not for use in pediatric patients) Usual Adult Dosage 2 mL (200 mg) t.i.d. or q.i.d. intramuscularly. NOTE: The injectable form is intended for intramuscular administration only; it is not recommended for intravenous use. Intramuscular administration may cause pain, stinging, burning, redness and swelling at the site of injection. Such effects may be minimized by deep injection into the upper outer quadrant of the gluteal region, and by avoiding the escape of solution along the route. Discard unused portion.
Read the full Dosage and Administration section on DailyMed →
Trimethobenzamide side effects
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Like all medications, trimethobenzamide can cause side effects. Commonly reported ones include:
Common side effects
- Drowsiness or sedation
- Dizziness
- Headache
- Diarrhea
- Blurred vision
- Muscle cramps
- Depression of mood or disorientation
- Pain, stinging, or redness at the injection site (injection form)
- Pain, stinging, burning, redness or swelling at the injection site (with the intramuscular form)
When to get medical help
- Call your doctor right away if you have sudden muscle spasms — especially in your head, neck, or eyes — as these may be signs of acute dystonic reactions (EPS)
- Seek medical help immediately if you experience seizures, coma, or severe confusion
- Contact your doctor if you notice yellowing of the skin or eyes (jaundice), which may signal liver problems
- Get help right away if you have signs of a serious allergic reaction such as swelling of the face or throat (angioedema) or a skin rash
- Tell your doctor if you develop unusual involuntary movements, restlessness, or tremors
- Seek care if you develop severe disorientation or a deeply depressed mood
More serious reactions — including seizures, coma, severe involuntary muscle movements (extrapyramidal symptoms), jaundice (yellowing of the skin or eyes), blood disorders, or severe allergic reactions including swelling of the face or throat — require immediate medical attention. Contact your doctor or go to the emergency room right away if any of these occur.
Trimethobenzamide warnings and precautions
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- Extrapyramidal symptoms (EPS): Trimethobenzamide can cause sudden, uncontrolled muscle spasms — especially in the head, neck, or eyes — as well as restlessness, tremors, and difficulty swallowing. These can be confused with signs of a serious brain condition. Tell your doctor immediately if these occur.
- Masking serious illness: Nervous system side effects from this drug can look like signs of a serious underlying condition (such as encephalopathy or Reye's syndrome). This makes careful diagnosis important, especially in children — one key reason this drug is not recommended for pediatric patients.
- Other serious CNS reactions: Coma, seizures, severe mood changes, and disorientation have been reported, especially when combined with alcohol or other CNS-depressant drugs.
- Liver toxicity (hepatotoxicity): This medication can harm the liver. Avoid it if you already have liver problems, and stop taking it immediately if liver issues develop.
- Driving and machinery: This drug can impair your thinking and physical coordination. Do not drive or use heavy equipment until you know how it affects you.
- Pregnancy and breastfeeding: Safety is not fully established. Discuss with your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
Trimethobenzamide interactions
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Trimethobenzamide can interact with several common drugs and substances, increasing the risk of serious side effects. Key interactions include:
- Alcohol: Significantly increases drowsiness and CNS depression — avoid alcohol while taking this medication
- Sedatives and sleep aids (hypnotics): Add to CNS depression and increase risk of confusion or sedation
- Opioid pain medications: Compound CNS-depressant effects
- Anti-anxiety medications (anxiolytics): May worsen drowsiness and movement-related side effects
- Antipsychotic medications: Increase the risk of extrapyramidal symptoms (EPS) — involuntary muscle movements; avoid combining if possible
- Anticholinergic drugs: May worsen CNS and movement-related side effects
Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.
Before taking Trimethobenzamide
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- Do not use the injectable form (Tigan or Trimethobenzamide Hydrochloride Injection) if you are allergic to trimethobenzamide
- The injectable forms are contraindicated (not allowed) in children
- The oral capsule form is not recommended for children due to serious CNS risks and the risk of worsening Reye's syndrome or other liver conditions
- Tell your doctor if you have kidney disease — your dosing schedule may need to be adjusted and your kidney function should be monitored
- Avoid this medication if you have signs or symptoms of liver impairment; stop taking it if liver problems develop during treatment
- Older adults are more likely to have reduced kidney function and may need a less frequent dosing schedule
- If you are pregnant, the safety of this drug is not fully established — discuss risks and benefits with your doctor
- If you are breastfeeding, it is not known whether this drug passes into breast milk — talk to your doctor before using it
- Do not drive or operate machinery until you know how this medication affects you
How your body processes Trimethobenzamide
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After an intramuscular injection, trimethobenzamide reaches its peak level in the blood in about 30 minutes. The oral capsule takes a bit longer — about 45 minutes to peak. Despite the different routes, the blood concentration profile over time is similar between the two forms. The drug is processed (metabolized) mainly through oxidation, producing a major breakdown product called trimethobenzamide N-oxide, though the activity of this metabolite in humans is not yet known.
Trimethobenzamide has a half-life (the time for the body to clear half the drug) of 7 to 9 hours. Between 30% and 50% of a single dose is excreted unchanged through the urine within 48 to 72 hours, which is why people with kidney problems may need dose adjustments.
How to store Trimethobenzamide
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Store between 20°C to 25°C (68°F to 77°F).
Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Supplements & herbs that interact with Trimethobenzamide
17 supplements and herbal products have documented interactions with Trimethobenzamide in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 1
- Moderate · 7
- Minor · 9
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
Trimethobenzamide: pharmacist answers to common questions
Quick, plain-English answers to the questions patients ask most about Trimethobenzamide — the kind of thing our pharmacy team would talk through with you at the counter.
What exactly does trimethobenzamide treat?
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Can I take this with my other medications?
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What side effects should I actually watch out for?
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Can I give this to my child?
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I'm older and also have some kidney problems — is this safe for me?
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I'm pregnant — can I use this for nausea?
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Is Trimethobenzamide available over the counter?
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When was Trimethobenzamide first available?
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Who makes Trimethobenzamide?
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Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More about Trimethobenzamide on HelloPharmacist
Trimethobenzamide forms and strengths (how it comes)
Trimethobenzamide is available in 2 forms. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see Trimethobenzamide inactive ingredients by manufacturer.
Injection
How this form is used
- Tigan is indicated for treatment of postoperative nausea and vomiting in adults
- Tigan is indicated for treatment of nausea associated with gastroenteritis in adults
- Trimethobenzamide Hydrochloride Injection is indicated for postoperative nausea and vomiting and nausea from gastroenteritis in adults
- Tigan injectable form is contraindicated (not allowed) in children
- Tigan and Trimethobenzamide Hydrochloride Injection are given by intramuscular injection only — never into a vein (intravenously)
- Injection into the upper outer area of the buttock (gluteal region) helps minimize pain, stinging, and swelling at the site
- Tigan dose should be adjusted for older adults or those with kidney impairment — your prescriber will determine the appropriate schedule
- Discard any unused portion of Trimethobenzamide Hydrochloride Injection after use
Capsule
How this form is used
- Treats postoperative nausea and vomiting in adults
- Treats nausea associated with gastroenteritis in adults
- Not recommended for use in children due to risk of serious nervous system effects and risk of worsening Reye's syndrome or other liver conditions
- Trimethobenzamide Hydrochloride capsules are taken by mouth several times daily; follow your prescriber's exact schedule
- Older adults and people with kidney impairment should take doses less frequently as directed by their prescriber
- Store Trimethobenzamide capsules at controlled room temperature (68°F to 77°F)
- Use the lowest effective dose and adjust based on response and tolerability, as directed by your prescriber
Trimethobenzamide on the U.S. market: products, makers and brands
How Trimethobenzamide appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
7 companies list 7 Trimethobenzamide product records with the FDA, mostly as injection, capsule; the earliest marketing or approval year on record is 1974. Brand names on the directory include Tigan; the rest are generics.
FDA-listed product records by dose form (tablet variants merged) — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
Also listed with the FDA, not a patient dose form: Powder (2) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
How widely Trimethobenzamide is used (Medicaid data)
A general measure of how commonly Trimethobenzamide is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Trimethobenzamide is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Trimethobenzamide prescribed? Of the 1,601 medications we measure, Trimethobenzamide ranks #1,247 by Medicaid prescriptions — more than 22% of them.
Utilization by Trimethobenzamide product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
2 ML trimethobenzamide hydrochloride 100 MG/ML Injection Most dispensed
Summed across the 1 of 4 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1726680
trimethobenzamide hydrochloride 300 MG Oral Capsule
Summed across the 1 of 21 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 860771
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Trimethobenzamide, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 2 of 25 listed Trimethobenzamide NDCs with Medicaid activity.
Compare Trimethobenzamide products
A representative set of FDA-listed product records for Trimethobenzamide — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Capsule | ||||
| 300 mg | Oral | Bryant Ranch Prepack | ANDA | View NDC → |
| 300 mg | Oral | Chartwell RX, LLC | ANDA | View NDC → |
| 300 mg | Oral | Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc. | ANDA | View NDC → |
| 300 mg | Oral | Lupin Pharmaceuticals,Inc. | ANDA | View NDC → |
| 💊Injection | ||||
| 100 mg/mL | Intramuscular | BPI Labs, LLC | ANDA | View NDC → |
| 100 mg/mL | Intramuscular | Henry Schein, Inc | NDA | View NDC → |
| 100 mg/mL | Intramuscular | Par Health USA, LLC | NDA | View NDC → |
Showing 7 of 7 products — FDA National Drug Code Directory. See every product, package size and price: browse all 7 Trimethobenzamide NDCs →
Trimethobenzamide side effects reported to the FDA (FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Trimethobenzamide — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Trimethobenzamide in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
Trimethobenzamide FDA approval history
How Trimethobenzamide went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
Trimethobenzamide recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
The FDA’s enforcement reports list no Trimethobenzamide recalls since July 2021.
✅No Trimethobenzamide recalls on record since July 2021Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 38685 4 dose forms · 7 strengths
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Dose form (SCDF) Injectable Solution RxCUI 374433In current FDA listingsClinical drug / strength (SCD) hydrochloride 100 MG/MLRxCUI 860749 -
Dose form (SCDF) Injection RxCUI 1726679In current FDA listingsClinical drug / strength (SCD) 2 ML trimethobenzamide hydrochloride 100 MG/MLRxCUI 1726680 -
Dose form (SCDF) Oral Capsule RxCUI 374227In current FDA listingsClinical drug / strength (SCD) hydrochloride 100 MGRxCUI 860752hydrochloride 250 MGRxCUI 860767hydrochloride 300 MGRxCUI 860771 -
Dose form (SCDF) Rectal Suppository RxCUI 374228No current FDA listingClinical drug / strength (SCD) 100 MGRxCUI 313489200 MGRxCUI 313492
Look up RxCUI 38685 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
Trimethobenzamide supply and shortage status
Whether Trimethobenzamide is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
Trimethobenzamide brand names
Trimethobenzamide is sold under one brand name in the FDA directory — Tigan. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who makes Trimethobenzamide: manufacturers and labelers
7 companies list Trimethobenzamide products with the FDA. By number of product records, the largest are BPI Labs, LLC, Bryant Ranch Prepack, Chartwell RX, LLC. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.
Trimethobenzamide drug class (RxNorm)
Trimethobenzamide belongs to the Antiemetic class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
Sources for this Trimethobenzamide page
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. BPI Labs, LLC is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →