Aceclidine

Mechanism of action

Aceclidine belongs to direct M-cholinomimetics: it directly activates muscarinic cholinoceptors of the parasympathetic nervous system. Unlike quaternary ammonium compounds (acetylcholine, muscarine), aceclidine is a tertiary ammonium compound without a permanent charge, ensuring better penetration across biological barriers.

Stimulation of M-cholinoceptors leads to the excitation of effector organs innervated by the parasympathetic system: smooth muscle tone of internal organs increases, exocrine gland secretion is enhanced, and heart rate decreases. Its spectrum of action is similar to pilocarpine, but it has lower toxicity, which broadens the possibilities for systemic use.

Pharmacological effects

Local action in ophthalmology: pupillary constriction (miosis) and spasm of accommodation lead to the opening of the anterior chamber angle and improvement of aqueous humor outflow through the trabecular meshwork. Intraocular pressure decreases for up to 6 hours following a single instillation.

Resorptive (systemic) action upon parenteral administration or oral intake:

• Increased tone of the smooth musculature of the gastrointestinal tract and urinary bladder
• Enhanced intestinal peristalsis
• Increased myometrial tone (uterine musculature)
• Stimulation of digestive gland secretion (salivary, gastric)
• Decreased heart rate, lowered blood pressure

It is clinically important to understand the indirect functional antagonism with myotropic antispasmodics (papaverine): the drugs exert opposite effects on smooth muscle tone, but through different sites of action—receptor-mediated mechanism for aceclidine versus direct influence on the cell's contractile apparatus for papaverine.

Indications for use

Topical (ophthalmology):

• Open-angle glaucoma — drug of choice for lowering IOP
• Acute angle-closure glaucoma attack (as part of combination therapy)

Systemic (oral, subcutaneous):

• Intestinal atonia — postoperative paresis, dynamic obstruction
• Urinary bladder atonia — neurogenic urinary retention
• Uterine hypotonia in the postpartum period
• Uterine bleeding in the postpartum period (to enhance myometrial contractions and stop bleeding)

For GI and bladder atonia, it can be prescribed alternatively or concurrently with anticholinesterase agents (neostigmine bromide).

Side effects and contraindications

Side effects are associated with M-cholinoceptor hyperstimulation and occur predominantly with systemic use:

• Hypersalivation (drooling), diarrhea
• Smooth muscle spasms (abdominal pain, frequent urination)
• Arterial hypotension, bradycardia
• Local irritant effect (upon instillation into the eye — burning sensation, conjunctival hyperemia)

Contraindications (pathogenetically justified):

• Bronchial asthma and COPD — risk of bronchospasm due to increased bronchial smooth muscle tone
• Angina pectoris, bradycardia — aggravation of cardiovascular pathology
• Peptic ulcer disease, hyperacid gastritis — stimulation of hydrochloric acid secretion exacerbates the condition
• Pregnancy (except for the postpartum period) — increased myometrial tone creates a risk of miscarriage

Management of complications: in case of arterial hypotension, $\alpha$-adrenomimetics are administered to increase vascular tone.

Administration guidelines and prescription

Formulations:

• Eye drops: 2%, 3%, 5% aqueous solutions
• Eye ointment: 3%, 5% — 20.0 g
• Solution for injection: 0.2% in 1 and 2 ml ampoules

Dosing regimen:

• Topically: 1–2 drops into the conjunctival sac 3–4 times a day
• Subcutaneously: 1–2 ml of 0.2% solution
• Maximum single and daily doses (MSD/MDD): 0.004 g / 0.012 g

Prescription example (topical use):

Rp.: Sol. Aceclidini 3% — 10 ml D.S. Eye drops. Instill 2 drops into both eyes 3 times a day.

Prescription example (parenteral administration):

Rp.: Sol. Aceclidini 0,2% — 1 ml D.t.d. N. 10 in amp. S. Administer subcutaneously 1 ml 2 times a day.

The drug is stored on List B. When prescribing systemically, consider the full spectrum of contraindications.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Comparative profile of M-cholinomimetics: pilocarpine, aceclidine, bethanechol, cevimeline
• Anticholinesterase agents as an alternative to direct cholinomimetics in GI atonia
• Mechanism of intraocular pressure reduction in glaucoma: the role of miosis and the anterior chamber angle
• Quaternary and tertiary ammonium compounds: differences in BBB permeability
• Types of antagonism in pharmacology: direct competitive, non-competitive, functional
• M-anticholinergics as antidotes in cholinomimetic overdose

Other topics in the «Drugs and Prescriptions» section

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