Melanosis coli, also pseudomelanosis coli, is a disorder of pigmentation of the wall of the colon, often identified at the time of colonoscopy. It is benign and may have no significant correlation with disease. The brown pigment is lipofuscin in macrophages, not melanin. Cause
The most common cause of melanosis coli is the extended use of laxatives, and commonly anthraquinone containing laxatives such as senna, aloe vera, and other plant glycosides. The anthranoid laxatives pass through the gastrointestinal tract unabsorbed until they reach the large intestine, where they are changed into their active forms. The resulting active compounds cause damage to the cells in the lining of the intestine and leads to apoptosis (a form of cell death). The damaged (apoptotic) cells appear as darkly pigmented bodies that may be taken up by scavenger cells known as macrophages. When enough cells have been damaged, the characteristic pigmentation of the bowel wall develops. The condition can develop after just a few months of laxative use.However, other causes are identified, including an increase in colonic epithelial apoptosis. Endoscopically, the mucosa may show a brownish discoloration in a moiré pattern. Histologic appearance
On biopsy, melanosis coli shows characteristic pigment-laden macrophages within the mucosa on PAS staining.The histologic differential diagnosis of mucosal pigmentation is: lipofuscin (melanosis coli), hemosiderin-laden macrophages, and melanin (rare). Prognosis
No adverse effects or consequences of melanosis coli have been identified.
Brompheniramine, sold under the brand name Dimetapp among others, is a first-generation antihistamine drug of the propylamine (alkylamine) class. 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.It was patented in 1948 and came into medical use in 1955. Side effects
Brompheniramines 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. 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 similar to other common antihistamines such as diphenhydramine. Brompheniramine is metabolised by cytochrome P450 isoenzymes in the liver. 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.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.