Demecarium bromide, trade name Humorsol, is a
carbamate
In organic chemistry, a carbamate is a category of organic compounds with the general formula and structure , which are formally derived from carbamic acid (). The term includes organic compounds (e.g., the ester ethyl carbamate), formall ...
parasympathomimetic drug that acts as an
acetylcholinesterase inhibitor
Acetylcholinesterase inhibitors (AChEIs) also often called cholinesterase inhibitors, inhibit the enzyme acetylcholinesterase from breaking down the neurotransmitter acetylcholine into choline and acetate, thereby increasing both the level and ...
, and is used as a
glaucoma medication. It is applied directly to the eye in order to reduce elevated
intraocular pressure
Intraocular pressure (IOP) is the fluid pressure inside the eye
Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response fu ...
associated with
glaucoma
Glaucoma is a group of eye diseases that result in damage to the optic nerve (or retina) and cause vision loss. The most common type is open-angle (wide angle, chronic simple) glaucoma, in which the drainage angle for fluid within the eye re ...
.
Demecarium causes constriction of the pupil (
), which improves the drainage of the fluid in the eye (
aqueous humour
The aqueous humour is a transparent water-like fluid similar to plasma, but containing low protein concentrations. It is secreted from the ciliary body, a structure supporting the lens of the eyeball. It fills both the anterior and the posteri ...
).
As demecarium reversibly inhibits
cholinesterase
The enzyme cholinesterase (EC 3.1.1.8, choline esterase; systematic name acylcholine acylhydrolase) catalyses the hydrolysis of choline-based esters:
: an acylcholine + H2O = choline + a carboxylate
Several of these serve as neurotransmitters ...
, it can be administered less frequently than other parasympathomimetic drugs, such as
carbachol.
Commercially produced demecarium bromide solution, previously sold under the trade name Humorsol,
is no longer available,
although solutions of demecarium can be
compounded.
Use in dogs
When administered with a topical
corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are in ...
, demecarium can delay the onset of
primary glaucoma in dogs.
High doses of demecarium may cause
organophosphate toxicity, particularly if flea treatments containing organophosphates are administered at the same time.
See also
*
Diisopropyl fluorophosphate
References
{{Acetylcholine metabolism and transport modulators
Acetylcholinesterase inhibitors
Bromides
Biscarbamates
Ophthalmology drugs
Quaternary ammonium compounds
Veterinary drugs
Bisquaternary anticholinesterases
Aromatic carbamates
Phenol esters