Ganglionic blocker
From Wikipedia, the free encyclopedia
A ganglionic blocker (or ganglioplegic) is a type of medication that
inhibits postganglionic transmission,[1] primarily by acting as a nicotinic antagonist.[2]
Because ganglionic blockers block the parasympathetic nervous system and sympathetic nervous
system, the effect of these drugs depends upon the dominant tone in the organ system. [3]
Examples
Examples include hexamethonium, pentolinium, mecamylamine, trimetaphan, and pempidine.
Others include:[4]
benzohexonium
chlorisondamine
pentamine
Uses
Ganglionic blockers are used less frequently now than they were in the past, because more selective
agents are now available. However, they are still used in some emergency situations, such as aortic
dissection.
Side-Effects
Cardiovascular: Orthostatic(postural) hypotension, Tachycardia
GIT: Dry-mouth, GIT atony,urine retention, digestive problems
Sexual Dysfunction: Failure of erection and ejaculation
Treatments and drugs
Glaucoma treatments reduce intraocular pressure by improving aqueous outflow, reducing the
production of aqueous, or both. Glaucoma can't be totally cured, and damage caused by the
disease can't be reversed, but treatment and regular checkups can prevent visual loss in people
with very early glaucoma. If visual loss has already occurred, treatment can slow or prevent
further vision loss.
Eyedrops
Glaucoma treatment often starts with medicated eyedrops. Be sure to use the drops exactly as
prescribed. Otherwise, your optic nerve damage could get even worse. If your doctor prescribes
more than one type of eyedrop, make sure to ask how long to wait between applications.
Because some of the eyedrops are absorbed into your bloodstream, you may experience side
effects unrelated to your eyes. To minimize this absorption, close your eyes for one to two
minutes after putting the drops in. Press lightly at the corner of your eye near your nose to close
the tear duct for one or two minutes, and wipe off any unused drops from your eyelid.
The types of most commonly prescribed eyedrops include:
Prostaglandin-like compounds. These eyedrops increase the outflow of aqueous
humor. Examples include latanoprost (Xalatan) and bimatoprost (Lumigan). Possible side effects
include mild reddening and stinging of the eyes and darkening of the iris, changes in the pigment
of the eyelid skin, and blurred vision from swelling of the retina.
Beta blockers. These reduce the production of aqueous humor. Examples include
timolol (Betimol, Timoptic), betaxolol (Betoptic) and metipranolol (Optipranolol). Possible side
effects include difficulty breathing, slowed pulse, hair loss, lower blood pressure, impotence,
fatigue, weakness, depression and memory loss. If you have asthma, bronchitis or emphysema,
medications other than beta blockers may be recommended because beta blockers may worsen
breathing problems. Your doctor also may recommend avoiding beta blockers if you're taking
insulin for diabetes.
Alpha-agonists. These reduce the production of aqueous humor and increase drainage.
Examples include apraclonidine (Iopidine) and brimonidine (Alphagan). Possible side effects
include fatigue, dizziness, red, itchy or swollen eyes, dry mouth and allergic reactions.
Carbonic anhydrase inhibitors. These also reduce the production of aqueous humor.
Examples include dorzolamide (Trusopt) and brinzolamide (Azopt). Frequent urination and a
tingling sensation in the fingers and toes are possible side effects, occurring more often with oral
carbonic anhydrase inhibitors than with anhydrase inhibitor eyedrops. If you have an allergy or
sensitivity to sulfa drugs, don't use these medications unless there's no alternative.
Miotic or cholinergic agents. These also increase the outflow of aqueous humor.
Examples include pilocarpine (Isopto Carpine) and carbachol (Isopto Carbachol). Possible side
effects are pain around or inside the eyes, brow ache, blurred or dim vision, nearsightedness,
allergic reactions, a stuffy nose, sweating, increased salivation, and occasional digestive
problems.
Epinephrine compounds. These compounds, such as dipivefrin (Propine), also
increase the outflow of aqueous humor. Possible side effects include red eyes, allergic reactions,
palpitations, increased blood pressure, headache and anxiety.
Oral medications
If eye drops alone don't bring your eye pressure down to the desired level, your doctor may also
prescribe an oral medication, usually in the form of a carbonic anhydrase inhibitor. Take these
pills with meals to reduce side effects.
Initially, carbonic anhydrase inhibitors may cause frequent urination and a tingling sensation in
your fingers and toes. After several days, these symptoms usually disappear. Other possible side
effects of carbonic anhydrase inhibitors include rashes, depression, fatigue, kidney stones,
lethargy, stomach upset, a metallic taste in carbonated beverages, impotence and weight loss.
