Trimethobenzamide

2.2

2.04

WHITE CRYSTALLINE POWDER; SLIGHT PHENOLIC ODOR; SOL IN WARM ALC; INSOL IN ETHER & BENZENE /HYDROCHLORIDE/

PKA: 8.27; FREELY SOL IN ETHANOL & CHLOROFORM; INSOL IN PETROLEUM ETHER /HYDROCHLORIDE/

3.98e-02 g/L

Serum aminotransferase elevations during trimethobenzamide therapy are uncommon and rates of such elevations have not been reported in large clinical trials. A single case report of hepatitis and jaundice attributed to trimethobenzamide was published in 1967 that predated availability of tests for hepatitis A, B and C and of modern imaging studies. The latency to onset was approximately 2 weeks and the pattern of injury was mixed. There were no immunoallergic or autoimmune features and recovery was prompt once the medication was stopped. Since that report, there has only been a single mention of possible hepatotoxicity due to trimethobenzamide, a somewhat prolonged case of hepatocellular injury with a cholestatic pattern on liver biopsy despite minimal jaundice. Thus, clinically apparent liver injury from trimethobenzamide must be very rare and is generally mild and self-limited in course.

...WITH LARGER DOSES, DROWSINESS, VERTIGO, DIARRHEA, CUTANEOUS HYPERSENSITIVITY REACTIONS, EXTRAPYRAMIDAL REACTIONS, & EXAGGERATION OF PRE-EXISTING NAUSEA HAVE OCCURRED. PAIN @ SITE OF INJECTION & LOCAL IRRITATION AFTER RECTAL ADMIN HAVE BEEN NOTED. /HYDROCHLORIDE SALT/

CASE REPORT. 2-WK-OLD MALE INFANT WAS WELL UNTIL 7 DAYS PRIOR TO ADMISSION. HE RECEIVED 3 RECTAL 100 MG DOSES IN 24 HR PERIOD PRIOR TO ADMISSION. HE BECAME LISTLESS, HYPOTONIC & CYANOTIC. EXTRAPYRAMIDAL REACTION SECONDARY TO DRUG WAS DIAGNOSIS.

DURING YR 1959-1966, TRIMETHOBENZAMIDE PRESCRIBED TO 11,481 PREGNANT WOMEN FOR NAUSEA & VOMITING IN 1ST 84 DAYS OF PREGNANCY, WAS EVALUATED FOR TERATOGENIC POTENTIAL. THERE WAS SLIGHT SUGGESTION OF EXCESS OF SEVERE CONGENITAL ANOMALIES.

HEPATITIS FOLLOWING THE ADMIN OF TRIMETHOBENZAMIDE HYDROCHLORIDE.

R - Respiratory system

QR - Respiratory system

Trimethobenzamide is a novel antiemetic which prevents nausea and vomiting in humans. Its actions are unclear but most likely involves the chemoreceptor trigger zone (CTZ). In dogs pretreated with trimethobenzamide HCl, the emetic response to apomorphine is inhibited, while little or no protection is afforded against emesis induced by intragastric copper sulfate.

The mechanism of action of trimethobenzamide as determined in animals is obscure, but may involve the chemoreceptor trigger zone (CTZ), an area in the medulla oblongata through which emetic impulses are conveyed to the vomiting center; direct impulses to the vomiting center apparently are not similarly inhibited.

DRUG...SHOWN TO INHIBIT STIMULI @ CHEMORECEPTOR TRIGGER ZONE IN ANIMALS... /HYDROCHLORIDE SALT/

Hepatic.

METABOLIZED IN THE LIVER OF THE DOG TO THE N-DESMETHYL AND N-OXIDE DERIVATIVES. ...IN /HUMAN/ ADULTS, FOLLOWING ORAL OR RECTAL ADMIN OF 500 MG...AN UNIDENTIFIED METABOLITE HAS BEEN DEMONSTRATED.

W2X096QY97

TRIMETHOBENZAMIDE

Established Pharmacologic Class [EPC] - Antiemetic

Physiologic Effects [PE] - Emesis Suppression

Trimethobenzamide is an Antiemetic. The physiologic effect of trimethobenzamide is by means of Emesis Suppression.