Trimethobenzamide

Trimethobenzamide
Clinical data
Trade names	Tigan, Tebamide
AHFS/Drugs.com	Monograph
MedlinePlus	a682693
Routes of; administration	Oral, rectal, intramuscular
ATC code	R06AA10 (WHO) ;
Legal status
Legal status	US: ℞-only;
Pharmacokinetic data
Bioavailability	60-100%
Elimination half-life	7 to 9 hours (mean)
Excretion	urine (30-50%), faeces
Identifiers
	IUPAC name N-{[4-(2-dimethylaminoethoxy)phenyl]methyl}-; 3,4,5-trimethoxy-benzamide;
CAS Number	138-56-7 ;
PubChem CID	5577;
IUPHAR/BPS	7614;
DrugBank	DB00662 ;
ChemSpider	5375 ;
UNII	W2X096QY97;
ChEBI	CHEBI:27796 ;
ChEMBL	ChEMBL1201256 ;
CompTox Dashboard (EPA)	DTXSID8023711 ;
ECHA InfoCard	100.004.848
Chemical and physical data
Formula	C21H28N2O5
Molar mass	388.464 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES O=C(c1cc(OC)c(OC)c(OC)c1)NCc2ccc(OCCN(C)C)cc2;
	InChI InChI=1S/C21H28N2O5/c1-23(2)10-11-28-17-8-6-15(7-9-17)14-22-21(24)16-12-18(25-3)20(27-5)19(13-16)26-4/h6-9,12-13H,10-11,14H2,1-5H3,(H,22,24) ; Key:FEZBIKUBAYAZIU-UHFFFAOYSA-N ;
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Trimethobenzamide (trade names Tebamide, Tigan) is an antiemetic used to prevent nausea and vomiting.

Mechanism of action

Trimethobenzamide is an antagonist of the D₂ receptor.^[1] It is believed to affect the chemoreceptor trigger zone (CTZ) of the medulla oblongata to suppress nausea and vomiting.

Side effects

Possible side effects include drowsiness, dizziness, headache, muscle cramps, and blurred vision. More serious adverse effects include skin rash, tremors, parkinsonism, and jaundice.

Formulations

Trimethobenzamide is marketed under the brand names Tebamide and Tigan, manufactured by GlaxoSmithKline and King Pharmaceuticals, respectively. It is available as oral capsules and injectable formulations.

Trimethobenzamide was also available as a rectal suppository, but such formulations were banned by the U.S. Food and Drug Administration on April 6, 2007, due to unproven efficacy.^[2]

Synthesis

Trimethobenzamide synthesis: Hoffmann La Roche, U.S. patent 2,879,293 (1959).

Alkylation of the sodium salt of p-hydroxybenzaldehyde (1) with 2-dimethylaminoethyl chloride affords the ether (2). Reductive amination of the aldehyde in the presence of ammonia gives diamine (3). Acylation of that product with 3,4,5-trimethoxybenzoyl chloride affords trimethobenzamide (4).

References

^ Smith HS, Cox LR, Smith BR (2012). "Dopamine receptor antagonists". Ann Palliat Med. 1 (2): 137–42. doi:10.3978/j.issn.2224-5820.2012.07.09. PMID 25841474.
^ Waknine, Yael (April 6, 2007). "FDA Bans Suppositories With Trimethobenzamide". Medscape. Retrieved 2007-04-06.^{[dead link‍]}

External links

Tebamide
Tigan (manufacturer's website)

[Smith2012-1] Smith HS, Cox LR, Smith BR (2012). "Dopamine receptor antagonists". Ann Palliat Med. 1 (2): 137–42. doi:10.3978/j.issn.2224-5820.2012.07.09. PMID 25841474.

[2] Waknine, Yael (April 6, 2007). "FDA Bans Suppositories With Trimethobenzamide". Medscape. Retrieved 2007-04-06.^{[dead link‍]}

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