Reviewed on 10/27/2022

What Is Trimethobenzamide and How Does It Work?

Trimethobenzamide is a prescription medication used to treat the symptoms of Nausea and Vomiting (Emesis) caused by stomach flu or post-surgery. 

  • Trimethobenzamide is available under the following different brand names: Tigan

What Are Side Effects Associated with Using Trimethobenzamide?

Common side effects of Trimethobenzamide include:

  • Headache,
  • Muscle cramps,
  • Dizziness,
  • Drowsiness,
  • Confusion,
  • Depressed mood,
  • Blurred vision,
  • Diarrhea, and
  • Pain, stinging, burning, redness, or swelling where the medicine was injected

Serious side effects of Trimethobenzamide include:

  • Hives,
  • Difficulty breathing,
  • Swelling of the face, lips, tongue, or throat,
  • Twitching or uncontrollable movements of the eyes, lips, tongue, face, arms, or legs,
  • Trouble speaking or swallowing,
  • Problems with thought or memory,
  • Pain, stiffness, or unusual muscle spasm in the neck,
  • Tremors,
  • Restlessness,
  • Inability to sit still,
  • Yellowing of the skin or eyes (jaundice),
  • Seizure,
  • Fever,
  • Chills,
  • Tiredness,
  • Mouth sores,
  • Skin sores,
  • Easy bruising,
  • Unusual bleeding,
  • Pale skin,
  • Cold hands and feet,
  • Lightheadedness, and
  • Shortness of breath

Rare side effects of Trimethobenzamide include:

  • none 

Seek medical care or call 911 at once if you have the following serious side effects:

  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Are the Dosages of Trimethobenzamide?

Adult and pediatric dosage


  • 300 mg

Injectable solution

  • 100 mg/ml


Adult and Geriatric dosage

  • 300 mg orally every 6-8 hours or
  • 200 mg intramuscular every 6-8 hours

Pediatric dosage

  • 20 mg/kg/day orally divided every 6-8 hours

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Other Drugs Interact with Trimethobenzamide?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • Trimethobenzamide has severe interactions with no other drugs.
  • Trimethobenzamide has severe interactions with the following drugs:
  • Trimethobenzamide has moderate interactions with the following drugs:
    • cenobamate
    • daridorexant
    • difelikefalin
    • difelikefalin and trimethobenzamide both increase sedation. Use Caution/Monitor.
    • midazolam intranasal
    • stiripentol
  • Trimethobenzamide has minor interactions with the following drug:
    • apomorphine

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Trimethobenzamide?


  • Hypersensitivity to drugs or excipients 

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Trimethobenzamide?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Trimethobenzamide?”


  • EPS and other CNS symptoms, which can occur in patients treated with may be confused with CNS signs of undiagnosed primary disease (. g, encephalopathy, metabolic imbalance, Reye’s syndrome); if CNS symptoms occur, evaluate risks and benefits of continuing therapy
  • Serious CNS adverse reactions such as coma, depression of mood, disorientation, and seizures reported; recent use of other drugs that cause CNS depression or EPS symptoms (. g, alcohol, sedatives, hypnotics, opiates, anxiolytics, antipsychotics, and anticholinergics) may also increase the risk for these serious CNS reactions; consider reducing daily dosage by increasing dosing interval or discontinuing the drug
  • Therapy is potentially hepatotoxic; avoid use in patients whose signs and symptoms suggest the presence of hepatic impairment; discontinue therapy in patients who develop impaired liver function while receiving the drug
  • Therapy can cause drowsiness and may impair mental and/or physical abilities needed to perform hazardous tasks (driving a motor vehicle or operating machinery); choose therapy over concomitant use of other drugs that cause CNS depression or EPS symptoms (. g, alcohol, sedatives, hypnotics, opiates, anxiolytics, antipsychotics, and anticholinergics), depending on the importance of the drug to a patient
  • Inform patients not to operate motor vehicles or other dangerous machinery until they are reasonably certain that therapy does not affect them adversely
  • Extrapyramidal symptoms
    • Extrapyramidal symptoms (EPS), manifested primarily as acute dystonic reactions, may occur; dystonic reactions may include sudden onset of muscular spasms, especially in the head and neck, or opisthotonos
    • Other EPS include laryngospasm, dysphagia, and oculogyric crisis; involuntary spasms of the tongue and mouth may lead to difficulty in speaking and swallowing; anticholinergic drugs can be used to treat acute dystonic reactions
    • EPS may include akathisia, restlessness, akinesia, and other parkinsonian-like symptoms 
    • (. g, tremor); depending on the severity of symptoms, reduce daily dosage by increasing dosing interval or discontinuing therapy
    • Avoid using the drugs in patients receiving other drugs that are likely to cause EPS (. g, antipsychotics)

Pregnancy and Lactation

  • Limited available data on pregnant women are not sufficient to inform a drug-associated risk for major birth defects and miscarriage.
  • Lactation
    • There is no information on the presence of the drug in human milk, the effects of the drug on the breastfed infant, or milk production; lack of clinical data during lactation precludes clear determination of the risk of the drug to infants during lactation
    • Consider the developmental and health benefits of breastfeeding along with the mother's clinical need for therapy and any potential adverse effects on the breastfed infant from the drug or underlying maternal condition

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