Brimonidine Health Dictionary

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Brimonidine: From 1 Different Sources

n. an alpha agonist (see sympathomimetic) used in the form of eye drops in the treatment of *glaucoma and ocular hypertension. The drug reduces the production of aqueous humour and increases its outflow from the eye; it may be used when beta-blocker eye drops are medically undesirable or are ineffective in controlling the glaucoma.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Glaucoma

n. a condition of the *optic nerve in which a loss of retinal nerve fibres leads to loss of vision. The most significant and manageable risk factor is the pressure in the eye. There are two types of primary glaucoma (in which no other ocular disease is present): acute and chronic simple. In acute (or angle-closure) glaucoma, there is an abrupt rise in pressure due to sudden closure of the angle of the anterior chamber between the cornea and iris where aqueous humour usually drains from the eye. This is accompanied by sudden and severe pain with marked blurring of vision associated with inflammation of the anterior segment. In the more common chronic simple (or open-angle) glaucoma, the pressure increases gradually, usually without any symptoms, and the visual loss is insidious. The same type of visual loss may also occur in eyes with a normal pressure: this is called normal (or low-tension) glaucoma. Primary glaucoma occurs increasingly with age and is an important cause of blindness. It is frequently hereditary. Secondary glaucoma may occur when other ocular disease impairs the normal circulation of the aqueous humour and causes the intraocular pressure to rise.

In all types of glaucoma the aim of the treatment is to reduce the intraocular pressure. Drugs used for this purpose include beta blockers (e.g. timolol, levobunolol, carteolol), carbonic anhydrase inhibitors (e.g. brinzolamide, dorzolamide), alpha-receptor stimulants (e.g. apraclonidine, brimonidine), and prostaglandin analogues (e.g. latanoprost, bimatoprost, travaprost, tafluprost). They can be used in the form of eye drops. If the medical treatment is ineffective, surgery may be performed to allow the aqueous humour to drain from the eye in sufficient quantities to enable the pressure to return to normal. Such operations may either make a new channel through which the aqueous drains (known as drainage or filtering operations) or involve the insertion of a narrow tube (tube surgery).... glaucoma

Sympathomimetic

adj. having the effect of stimulating the *sympathetic nervous system. The actions of sympathomimetic drugs are adrenergic: they act on alpha or beta *adrenoceptors. Alpha-adrenergic stimulants (alpha agonists) stimulate alpha receptors. They include *vasoconstrictors (e.g. *ephedrine, *phenylephrine, *metaraminol), used to treat nasal congestion and severe hypotension, and the selective ?2 agonists *apraclonidine and *brimonidine, which are used in the treatment of glaucoma. Beta-adrenergic stimulants (beta agonists) stimulate ?1 and/or ?2 adrenoceptors. ?2 agonists such as *salbutamol, *salmeterol, and *terbutaline relax bronchial smooth muscle and are used as *bronchodilators. Some ?2 agonists, including salbutamol, relax uterine muscle and are sometimes used in the treatment of premature labour (see tocolytic). ?1 agonists (e.g. *dobutamine) stimulate ?1 receptors in the heart and are therefore used for their *inotropic effects.... sympathomimetic

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