Brompheniramine, sold under the brand name Dimetapp among others, is a first-generation antihistamine drug of the propylamine (alkylamine) class.[1] 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.[1]
It was patented in 1948 and came into medical use in 1955.[2] In 2021, the combination with dextromethorphan and pseudoephedrine was the 294th most commonly prescribed medication in the United States with more than 500,000 prescriptions.[3] [4]
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.[5]
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[6] similar to other common antihistamines such as diphenhydramine.
Brompheniramine is metabolised by cytochrome P450 isoenzymes in the liver.
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.[1] [7]
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.[8] [9]
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.[10]
Brand names include Bromfed, Dimetapp, Bromfenex, Dimetane, and Lodrane. All bromphemiramine preparations are marketed as the maleate salt.[1]