Skip to Content

Benzacot Side Effects

Generic Name: trimethobenzamide

Note: This page contains information about the side effects of trimethobenzamide. Some of the dosage forms included on this document may not apply to the brand name Benzacot.

Not all side effects for Benzacot may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to trimethobenzamide: intramuscular solution, oral capsule

In addition to its needed effects, some unwanted effects may be caused by trimethobenzamide (the active ingredient contained in Benzacot). In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking trimethobenzamide:

  • Body spasm, with head and heels bent backward and body bowed forward
  • convulsions (seizures)
  • depression
  • shakiness or tremors
  • skin rash
  • sore throat or fever
  • unusual tiredness
  • vomiting (severe or continuing)
  • yellow eyes or skin

Some of the side effects that can occur with trimethobenzamide may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common
  • Drowsiness
Less common
  • Blurred vision
  • diarrhea
  • dizziness
  • headache
  • muscle cramps

For Healthcare Professionals

Applies to trimethobenzamide: compounding powder, intramuscular solution, oral capsule, rectal suppository

Nervous system

Extrapyramidal reactions to trimethobenzamide (the active ingredient contained in Benzacot) have been reported in some patients, the youngest of whom was 2 weeks old. This patient received approximately 300 mg rectally, although the drug is not recommended for newborn infants.[Ref]

Nervous system adverse effects have included dizziness, drowsiness, headache, disorientation, coma, convulsions, depression of mood, opisthotonus, Parkinson's-like symptoms, trismus, and extrapyramidal symptoms.[Ref]


Hypersensitivity reactions have included allergic-type skin reactions.[Ref]


Cardiovascular side effects have been reported rarely. Hypotension has been occasionally associated with intramuscular administration in surgical patients.[Ref]


Psychiatric side effects have included depression.[Ref]


Gastrointestinal adverse effects include diarrhea.[Ref]


Hepatic side effects have included reports of jaundice and hepatotoxicity.[Ref]

An isolated case report described a 50-year-old white female receiving trimethobenzamide capsules during a study protocol for use as a prophylactic antiemetic. After two days of administration, the patient had become jaundiced and her urine was dark. She felt tired, anorexic and nauseated with mild epigastric pain. A liver scan four days after the episode indicated hepatocellular dysfunction. She denied any other factors which may have contributed to the episode.[Ref]


Muscle cramps have occurred in some patients.[Ref]


Hematologic side effects have rarely included blood dyscrasias.[Ref]


Ocular side effects have included reports of blurring of vision.[Ref]


The manufacturer recommends giving trimethobenzamide (the active ingredient contained in Benzacot) by deep injection into the upper outer quadrant of the gluteal region, and avoiding the escape of the injectable solution along the route, in order to reduce the incidence of side effects at the injection site.[Ref]

Dermatologic side effects reported following intramuscular injection have included pain, stinging, burning, redness and swelling at the site of injection.[Ref]


1. Holmes C, Flaherty RJ "Trimethobenzamide HCL (Tigan)-induced extrapyramidal dysfunction in a neonate." J Pediatr 89 (1976): 669-70

2. "Product Information. Tigan (trimethobenzamide)." Monarch Pharmaceuticals Inc, Bristol, TN.

3. Borda I, Jick H "Hepatitis following the administration of trimethobenzamide hydrochloride." Arch Intern Med 120 (1967): 371-3

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.