Glaucoma lower intraocular pressure

Glaucoma Lowering intraocular pressure (lOP) in patients with chronic open-angle glaucoma and intraocular hypertension. 

For example, PGF201 agonists such as latanaprost have been developed as eyedrops to reduce intraocular pressure for the treatment of glaucoma. Topical instillation of these agonists is effective in lowering intraocular pressure and may be used as a first-line therapy for the treatment of glaucoma. 

Open-angle glaucoma, secondary glaucoma, preoperatively to lower Intraocular pressure (IOP), edema due to CHF, drug-induced edema, centrencephalic epilepsy Glaucoma... 

Glaucoma For adjunctive treatment of chronic simple (open-angle) glaucoma and secondary glaucoma preoperatively in acute angle-closure glaucoma when delay of surgery is desired to lower intraocular pressure (lOP). 

Epinephrine also has been used to lower intraocular pressure in open-angle glaucoma. Its use promotes an increase in the outflow of aqueous humor. Because epinephrine administration will decrease the filtration angle formed by the cornea and the iris, its use is contraindicated in angle-closure glaucoma under these conditions the outflow of aqueous humor via the filtration angle and into the venous system is hindered, and intraocular pressure may rise abruptly. 

Bimatoprost is an analogue of PGF, used to treat glaucoma. It is believed to lower intraocular pressure by increasing the outflow of aqueous humor through both the trabecular meshwork and uveoscleral routes. 

Physostigmine (eserine sulfate) causes miosis and spasm of accommodation it also lowers intraocular pressure and hence can be used in the treatment of wide-angle glaucoma. As it is lipid soluble, it penetrates into the brain rapidly, raises the acetylcholine concentration and, in toxic amounts, may cause cholinergic CNS toxicity, which is characterized by restlessness, insomnia, tremors, confusion, ataxia, convulsions, respiratory depression, and circulatory collapse. These effects are reversed by atropine. 

There are two features of the cannabinoids which may ultimately be of therapeutic importance. THC lowers intraocular pressure, which may be of benefit in the treatment of glaucoma. There is also evidence that THC is a moderately effective antiemetic agent. Such a discovery has led to the development of nabilone, a synthetic cannabinoid, as an antiemetic agent, but its use is limited because of the dysphoria, depersonalization, memory disturbance and other effects which are associated with the cannabinoids. Whether the bronchodilator action of THC will ever find therapeutic application in the treatment of asthma remains an open question. 

Dorzolamide can be applied topically to the eye to lower intraocular pressure in glaucoma (p.346). 

The cannabinoids tested so far appear to be of limited use in the treatment of glaucoma. They appear to act only against a primary (but not sole) symptom of the disease (i.e., ocular hypertension), rather than against the underlying disease process, which remains uncertain. The side-effects of those cannabinoids particularly effective in lowering intraocular pressure (IOP) restrict their clinical usefulness (with some exceptions such as canna-bigerol). Cannabinoids administered intraocularly to humans cause no IOP reduction. ... 

Figure 10-11 Effect of brimonidine 0.2% and timolol 0.5% at peak 2 hours after morning drug instillation. Asterisks indicate statistically lower intraocular pressure with brimonidine at week 1, week 2, month 3, and month 12. (Adapted from Katz LJ. Brimomdine tartrate 0.2% twice daily versus timolol 0.5% twice daily 1-year results in glaucoma patients.Am J Ophthalmol 1999 127 20-26.)...

To lower intraocular pressure in chronic simple glaucoma (pilocarpine)... 

Reduction of intraocular pressure. This action is due not to diuresis (thiazides actually raise intraocular pressure slightly). The formation of aqueous humour is an active process requiring a supply of bicarbonate ions, which depends on carbonic anhydrase. Irrhibition of carbonic anhydrase reduces the formation of aqueous humour and lowers intraocular pressure. This is a local action and is not affected by the development of acid-base changes elsewhere in the body, i.e. tolerance does not develop. In patients with acute glaucoma, acetazolamide can be taken either orally, or intravenously. Acetazolamide is not recommended for long-term use because of the risk of hypokalaemia and acidosis, but brinzolamide or dorzolamide are effective as eye drops, well tolerated, and thus suitable for chronic use in glaucoma. 

Clinica use Primarily as an antihypertensive agent. Also used for controlling ventricular rate in AF, post-Mi,CHF, angina, and hyperthyroidism. Additionally, propranolol maybe used for migraine headaches, essential tremors, and anxiety. The nonselectlve faeta-blockers are useful in the treatment of hepatic portal hypertension in patients with liver cirrhosis. Topical agents are used to lower intraocular pressures in patients with glaucoma. 

Figure 28-28 Dorzolamide (Trusopt), 1. also a constituent of Cosopt, was the first drug designed with structure-based CAOO methods to become commercially available. MK-927. 21, IS a close structural analogue and was the first carbonic anhydrase inhibitor to lower intraocular pressure In glaucoma patients...

Functional FP receptors have also been demonstrated in the myometrium of some rodents and also humans (95, 96). However, in dogs, FP receptor agonists are lethal— probably as a result of the presence of contractile FP receptors on airway smooth muscle (61). This has yet to be reported in any other species. FP receptors are also present in iris sphincter muscles, and the ocular actions mediated by these receptors have been exploited to lower intraocular pressure and in glaucoma treatment in humans. 

The major indication for carbonic anhydrase inhibitors is open-angle glaucoma. Carbonic anhydrase inhibitors also may be employed for secondary glaucoma and preop-eratively in acute angle-closure glaucoma to lower intraocular pressure before surgery. Acetazolamide also is used for the treatment of epilepsy. The rapid development of tolerance, however, may limit the usefulness of carbonic anhydrase inhibitors for epilepsy. 

Dorzolamide is a carbonic anhydrase inhibitor that inhibits carbonic anhydrase enzyme, reducing the rate of aqueous humor formation and thus lowering intraocular pressure (lOP). It is indicated in the treatment of elevated lOP in patients with ocular hypertension or open-angle glaucoma. 

FIGURE 77 Physostigmine causes miosis and spasm of accommodations it also lowers intraocular pressure and hence can be used in the treatment of wide-angle glaucoma. 

Timolol (10 mg t.i.d.) alone or in combination with other antihypertensive agents, such as thiazide diuretics, is used in the management of hypertension. Timolol is indicated for the treatment of myocardial infarction and prophylaxis of migraine headaches. Timolol (1 drop of 0.25% solution twice daily) is effective in lowering intraocular pressure in patients with chronic open-angle glaucoma. 

Brimonidine (alphagan), a clonidine derivative and agonist, is administered topically to lower intraocular pressure in patients with ocular hypertension or open-angle glaucoma brimonidine both decreases aqueous humor production and increases outflow (see Chapter 63). Unlike cqrra-clonidine, brimonidine crosses the blood—brain barrier and can produce hypotension and sedation, although these effects are slight compared to those of clonidine. 

Diclofenamide is employed to lower intraocular pressure by reducing the rate of secretion of aqueous humor. It is recommendedfor the treatment of both primary and secondary glaucoma. Though it possesses inherent diuretic properties it is not promoted for this purpose. It produces less acidotic refractoriness to diuretic action than acetazolamide. 

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