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Benzocaine / trimethobenzamide Side Effects

For the Consumer

Applies to benzocaine / trimethobenzamide: suppositories

Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Dizziness; drowsiness; rectal irritation.

Seek medical attention right away if any of these SEVERE side effects occur while taking benzocaine / trimethobenzamide:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); loss of balance; seizures; shuffling walk; uncontrolled movements of the arms or legs; yellowing of the skin or eyes.

For Healthcare Professionals

Applies to benzocaine / trimethobenzamide: rectal suppository


Cardiovascular side effects have included hypotension. It has been occasionally associated with intramuscular administration of trimethobenzamide in surgical patients.[Ref]


Gastrointestinal side effects have included diarrhea.[Ref]


Hematologic side effects have rarely included blood dyscrasias. Methemoglobinemia, characterized by cyanosis, has been reported with the use of benzocaine topical.[Ref]


Hepatic side effects have included hepatotoxicity and jaundice associated with the use of trimethobenzamide.[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]


Hypersensitivity side effects have included allergic-type skin reactions. Bronchospasm, shock, and anaphylactoid reactions may occur and, in general, have occurred with high plasma levels of the local anesthetic. Parkinson-like symptoms have been reported following the use of trimethobenzamide. These have abated following drug discontinuation, but in some cases treatment may be indicated.[Ref]


Musculoskeletal side effects have included muscle cramps associated with the use of trimethobenzamide.[Ref]

Nervous system

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

Extrapyramidal reactions to trimethobenzamide 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]


Psychiatric side effects have included depression.[Ref]


Local side effects have included burning, stinging, tenderness, and sloughing following the use of benzocaine topical. Pain has been reported following the intramuscular administration of trimethobenzamide.[Ref]


Ocular side effects have included blurred vision following the use of trimethobenzamide.[Ref]


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

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

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.