Brompheniramine

Brompheniramine, sold under the brand name Dimetapp among others, is a first-generation antihistamine drug of the propylamine (alkylamine) class.^[2] It is indicated for the treatment of the symptoms of the common cold and allergic rhinitis, such as runny nose, itchy eyes, watery eyes, and sneezing. Like the other first-generation drugs of its class, it is considered a sedating antihistamine.^[2]

Brompheniramine

Clinical data
Trade names	Bromfed, Dimetapp, Bromfenex, others
AHFS/Drugs.com	Monograph
MedlinePlus	a682545
Routes of administration	By mouth
ATC code	R06AB01 (WHO)
Legal status
Legal status	AU: S4 / S3 / S2 US: Rx-only / OTC
Pharmacokinetic data
Metabolism	Liver
Elimination half-life	24.9 ± 9.3 hours[1]
Excretion	Kidney
Identifiers
IUPAC name (R/S)-3-(4-Bromophenyl)-N,N-dimethyl-3-pyridin-2-yl-propan-1-amine
CAS Number	86-22-6 Y
PubChem CID	6834
IUPHAR/BPS	7133
DrugBank	DB00835 Y
ChemSpider	6573 Y
UNII	H57G17P2FN
KEGG	D07543 Y
ChEBI	CHEBI:3183 Y
ChEMBL	ChEMBL811 Y
CompTox Dashboard (EPA)	DTXSID5022691
ECHA InfoCard	100.001.507
Chemical and physical data
Formula	C16H19BrN2
Molar mass	319.246 g·mol−1
3D model (JSmol)	Interactive image
SMILES Brc1ccc(cc1)C(c2ncccc2)CCN(C)C
InChI InChI=1S/C16H19BrN2/c1-19(2)12-10-15(16-5-3-4-11-18-16)13-6-8-14(17)9-7-13/h3-9,11,15H,10,12H2,1-2H3 Y Key:ZDIGNSYAACHWNL-UHFFFAOYSA-N Y
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It was patented in 1948 and came into medical use in 1955.^[3] In 2022, the combination with dextromethorphan and pseudoephedrine was the 265th most commonly prescribed medication in the United States, with more than 1 million prescriptions.^[4][5]

Side effects

Brompheniramine's effects on the cholinergic system may include side-effects such as drowsiness, sedation, dry mouth, dry throat, blurred vision, and increased heart rate. It is listed as one of the drugs of highest anticholinergic activity in a study of anticholinergenic burden, including long-term cognitive impairment.^[6]

Pharmacology

Brompheniramine works by acting as an antagonist of histamine H₁ receptors. It also functions as a moderately effective anticholinergic agent, and is likely an antimuscarinic agent^[7] similar to other common antihistamines such as diphenhydramine.

Brompheniramine is metabolised by cytochrome P450 isoenzymes in the liver.^[7]

Chemistry

Brompheniramine is part of a series of antihistamines including pheniramine (Naphcon) and its halogenated derivatives and others including fluorpheniramine, chlorpheniramine, dexchlorpheniramine (Polaramine), triprolidine (Actifed), and iodopheniramine. The halogenated alkylamine antihistamines all exhibit optical isomerism; brompheniramine products contain racemic brompheniramine maleate, whereas dexbrompheniramine (Drixoral) is the dextrorotary (right-handed) stereoisomer.^[2][8]

Brompheniramine is an analog of chlorpheniramine. The only difference is that the chlorine atom in the benzene ring is replaced with a bromine atom. It is also synthesized in an analogous manner.^[9][10]

History

Arvid Carlsson and his colleagues, working at the Swedish company Astra AB, were able to derive the first marketed selective serotonin reuptake inhibitor, zimelidine, from brompheniramine.^[11]

Names

Brand names include Bromfed, Dimetapp, Bromfenex, Dimetane, and Lodrane. All bromphemiramine preparations are marketed as the maleate salt.^[2]