Pupil constrictor drops

The pupil can dilate in diameter for various reasons. A pair of main muscles that make the pupil wider or narrower are responsible for regulating the diameter: the ciliary and radial muscles. A spasm of the first muscle narrows the pupil, and its weakness widens it. The second muscle provokes the opposite effect. Drops that narrow the pupil cause forced contraction of the ciliary muscle and relaxation of the radial muscle - this effect is often used by ophthalmologists to visually stabilize the size of the pupils. [ 1 ]

[ 2 ]

Indications for the use of pupil-constricting drops

Medicines that act to constrict the pupil may be used in the following situations:

• in low light conditions, when the large diameter of the pupil allows a large amount of light flux to be projected onto the retinal area;
• with excessive activity of the sympathetic nervous system (for example, after stressful situations);
• in case of pathologies in the brain (for example, tumors);
• with dilation of the pupils associated with chemical intoxication or taking medications;
• for eye diseases (eg glaucoma);
• before and after eye surgeries and manipulations, in case of injuries that could provoke weakening of the ciliary muscle;
• in case of paralysis of the eye muscles caused by tuberculosis, high intracranial pressure, poisoning, etc.;
• for diseases of the central nervous system that may be accompanied by spasm of the eye muscles (for example, with meningitis, poliomyelitis, etc.).

Release form

Eye drops are produced in the form of a medicinal solution, in a plastic or glass bottle with a dispenser or pipette. The packaging must indicate the name of the drug, the active substance, as well as the date of manufacture and the expiration date of the drug.

These products are intended to prevent or treat eye diseases. The composition of the drug may be represented by one or several active ingredients. The peculiarity of eye drops is their ability to overcome the conjunctiva, the outer eye shell, in a short time, to get to various parts of the eyeball, including the deep ones.

They are generally available without a prescription, but their use should be agreed upon with an ophthalmologist.

Pharmacodynamics

Medicines that constrict the pupil are called miotics. These medicines include cholinomimetic and anticholinesterase agents.

Cholinomimetics act on the principle of acetylcholine, and anticholinesterase drugs inhibit the action of cholinesterase, an enzyme that breaks down acetylcholine.

The dynamics of the effect of miotic drugs on intraocular pressure indicators consists of their unblocking effect on the area of the anterior eye chamber (angle) and the venous sinus of the sclera. Miotics provoke pupil constriction, the withdrawal of the iris from the area of the anterior eye chamber and the opening of closed areas of the angle. This scheme of action plays a huge role in the closed-angle form of glaucoma.

In the open-angle form of the disease, miotic agents “free” the venous sinus of the sclera and trabecular clefts, increasing the contractility of the ciliary muscle.

Pharmacokinetics

The percentage of active substances of miotic agents can reach the maximum level within 30 minutes after instillation.

Active substances are excreted through their natural outflow, without accumulation or signs of metabolism.

Eye drops easily penetrate the corneal layer and interact with eye tissues. The half-life can be from one and a half to two hours, and the effect of the active component that affects the constriction of the pupil can last much longer - on average 5-15 hours.

Method of administration and dosage

We present to your attention the most common names of drops that constrict the pupils, as well as the principles of their use and dosage.

• Pilocarpine hydrochloride 1-2% water-based solution, applied 1-2 drops up to 4 times a day. Pilocarpine-based preparations: Oftan Pilocarpine, Isopto-carpine. [ 3 ]
• Aceclidine 2%, 3%, 5% water-based solution. Drip from 3 to 6 times a day, depending on the effectiveness. Synonyms of the drug: Glaucostat, Glaudin, Glaunorm. [ 4 ]
• Carbacholine 0.5-1% solution. Used for instillation into the conjunctival sac 2 to 6 times a day. Effective for 4-6 hours. [ 5 ]
• Carbachol 3%, with the active ingredient carbamylcholine chlorate. Dosage: 1 drop 2 to 4 times a day.
• Proserin (Prostigmine) 0.5% solution, use 1 drop up to 4 times a day. [ 6 ]
• Carbacel (Isoptocarbachol) 0.75%, 1.5%, 2.25% and 3% solutions. Use 1 drop 2 to 6 times a day. [ 7 ]
• Armin 0.01% drops, applied 2-3 times a day.
• Physostigmine 0.25%-1% solution, is administered into the conjunctival sac 1 to 6 times a day. Synonyms: Ezerine salicylate. [ 8 ]
• Phosphacol – use 1-2 drops of a 0.013% aqueous solution 1:7500, twice a day. Synonyms: Mintacol, Solyuglaucit, Myotizal, Paraoxon. [ 9 ]

All of the listed drugs are considered potent agents that are not intended for long-term use and are prescribed only by specialists when there are appropriate indications.

Using constricting eye drops during pregnancy

The use of cholinomimetics and anticholinesterase drugs should be limited as much as possible during pregnancy and breastfeeding. Most cholinomimetic agents have the property of increasing the tone of the myometrium, which does not allow their use by pregnant women.

Any use of the listed drugs must be agreed upon with a doctor in advance - self-administration of these drugs is unacceptable.

Contraindications for use

Contraindications to the use of pupil constricting drops are:

• period of pregnancy and breastfeeding;
• tendency to allergic reactions;
• bronchial asthma;
• chronic course of heart failure;
• ischemic heart disease;
• bleeding in the digestive tract;
• epileptic seizures;
• acute inflammation of the abdominal organs;
• corneal defects, iritis, iridocyclitis;
• hypertension;
• obstructive or mechanical intestinal obstruction;
• ulcer of the gastric mucosa or duodenum;
• diabetes mellitus;
• spastic pain, myotonia, hyperkinesis;
• various types of shock states.

Side effects

The use of cholinomimetic agents may be accompanied by the following symptoms:

• manifestations of allergies;
• lowering blood pressure;
• narrowing of the lumen of the heart vessels;
• slowing of heart rate;
• heart rhythm disturbances;
• facial flushing;
• dyspnea;
• hyperhidrosis;
• increased intestinal motility, diarrhea;
• swelling, clouding of the cornea.

The use of drops based on anticholinesterase agents may be accompanied by the following side effects:

• dyspeptic disorders;
• salivation, lacrimation;
• slowing of the heart rate, conduction disturbances;
• convulsive syndrome, myasthenia, muscle tremors;
• headache, dizziness;
• sleep disorders;
• hypersensitivity reaction (skin rash, conjunctivitis, itching).

Overdose

Signs of overdose are manifested by a marked increase in side effects, including the occurrence of significant cardiovascular failure and respiratory dysfunction. Cataracts, lens opacity, and follicular conjunctivitis may develop.

Treatment consists of monitoring the heart rate, stabilizing blood pressure and respiratory function. Atropine is administered intravenously or subcutaneously in the amount of 0.5-1 mg, epinephrine in the amount of 0.3-1 mg subcutaneously or intramuscularly. The patient is asked to drink a large amount of fluid. If necessary, an infusion is administered.

Interactions of pupil-constricting drops with other drugs

The miotic effect of cholinomimetic agents is enhanced by ß-adrenoblockers, anticholinesterase drugs and α-adrenostimulants. The effect of drops is reduced by tricyclic antidepressants, m-anticholinergics, phenothiazines. Side effects are more pronounced under the influence of Fluorothane and Quinidine.

Anticholinesterase drugs enhance the effect of drugs aimed at suppressing the central nervous system (including ethyl alcohol). Simultaneous use with Ipidacrine reduces the effectiveness of local anesthetics, antibiotics, potassium chloride.

Storage conditions

Miotic drugs are stored in cool, dark places, maintaining a temperature regime of 8 to 15°C. Medicines can be stored in the refrigerator, provided that children have difficult access to the place where the medicines are stored.

An opened bottle should be used within no more than one month, otherwise the drug will lose its medicinal properties.

The shelf life of the drops is from 2 to 3 years, which must be indicated on the packaging and on the bottle with the medicine.

Drops that constrict the pupil may only be used as prescribed by a doctor and under constant monitoring of intraocular pressure. Independent and long-term use of these drugs is unacceptable.