MIOTICS – INTRODUCTION
Drugs that constrict the pupil.
Miotics are either parasympathomimetic (cholinergic-stimulating) drugs which have a direct muscarinic action, such as pilocarpine and carbachol, or anticholinesterase drugs which block the effect of acetylcholinesterase thus letting acetylcholine produce its effect, such as physostigmine, neostigmine, echothiophate and demecarium. There are also some miotics which act by blocking α-or β-adrenergic receptors. For example, dapiprazole and thymoxamine block the α-adrenergic receptors and propranolol blocks the β-adrenergic receptors.
Miotics are eye drops that stimulate the parasympathetic nervous system causing the pupil of the eye to become smaller. They reduce intraocular pressure by increasing the outflow of eye fluids from the eye and they are usually used to reverse angle-closure glaucoma or prevent angle-closure in eyes with narrow chamber angles. Pilocarpine (one of the miotics) has been used for almost 150 years for the treatment of glaucoma. It is rarely utilized today to treat open-angle glaucoma.
MIOTICS – INDICATION
They may be used in the treatment of glaucoma and accommodative esotropia and, sometimes, after a mydriatic examination.
MIOTICS – INFORMATION
Miotics is another class of medication that can be used to treat glaucoma. Miotics have been on the market for a very long time, and so some of the side effects may be a brow ache. It also makes your pupil very small. But miotics work differently than the other classes of medications because it actually increases outflow and lowers the pressure. And once again, we know if we can lower the pressure, we can stabilize your glaucoma.
Pilocarpine, a parasympathomimetic drug used in the treatment of glaucoma, produces a variety of ocular and systemic adverse reactions. Ocular side effects include miosis, accommodative spasm, frontal headaches, twitching lids, conjunctival injection, cataractous changes, allergic reactions, iris cysts, retinal detachment, increased permeability of the blood-aqueous barrier, anterior chamber narrowing, and the potential for inducing an acute angle-closure attack. Systemic side effects include nausea, vomiting, tenesmus, abdominal spasm, salivation, lacrimation, sweating, pulmonary edema, and bronchial spasm. The systemic side effects can best be minimized initially through proper use of the medication and nasolacrimal occlusion. The Ocusert, a long-acting pilocarpine-incorporated ocular insert, is a recent advance in delivery technique that offers an adequate hypotensive action with fewer side effects. Pilopex is a promising new experimental pilocarpine polymer salt presently being studied in Israel. Photomydriasis, a process involving the use of a laser to enlarge miotic pupils also offers help for these patients. N-demethylated carbachol is a new parasympathomimetic drug currently under study for glaucoma therapy. Initial results show that it may have considerable ocular hypotensive action with fewer adverse effects.