How Do Peripheral Acetylcholinesterase Inhibitors Work?

Peripheral acetylcholinesterase inhibitors also known as cholinesterase inhibitors are drugs that prevent the breaking down of acetylcholine and increase the duration of action and acetylcholine levels in the nerve endings called synapses. These drugs are used for the reversal of neuromuscular blockade following anesthesia and symptomatic treatment in patients with myasthenia gravis by improving muscle tone.

Acetylcholine is an essential neurotransmitter of the parasympathetic system which is part of the autonomic nervous system. Acetylcholine is released into space between two neurons (synaptic cleft) by the presynaptic neuron. Some important functions of acetylcholine in the peripheral nervous system include:

• Vasodilation
• Smooth muscle contractions
• Decrease heart rate
• Increased secretion of bodily fluids such as:
  • saliva and mucus 
  • gastric secretions
  • aqueous humor in the eye
  • urine

Acetylcholinesterase is concentrated in the synaptic cleft and hydrolyzes acetylcholine into acetate and choline, decreasing acetylcholine levels before it reaches the postsynaptic neuron. Peripherally acting acetylcholinesterase inhibitors are reversible inhibitors of acetylcholinesterase that come under the functional group, quaternary or tertiary ammonium group.

Peripheral acetylcholinesterase inhibitors are used to treat:

• Myasthenia gravis
• Congenital myasthenic syndromes
• Reversal of neuromuscular block caused by anesthesia and other muscle relaxants
• Glaucoma
• Anticholinergic toxicity symptoms
  • Tachycardia
  • Delirium
  • Mydriasis
  • Urinary retention
  • Dry skin
  • Ileus

Side effects of peripheral acetylcholinesterase inhibitors include:

• Nausea and vomiting
• Diarrhea
• Abdominal pain
• Trouble breathing
• Decreased blood pressure
• Decreased heart rate
• Excessive sweating
• Hallucinations
• Blurred vision

Other serious side effects of peripheral acetylcholinesterase inhibitors may include:

• Cardiac arrest
• Anaphylaxis (life-threatening allergic reactions)
• Seizures

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of peripheral acetylcholinesterase inhibitors include:

• Neostigmine (Bloxiverz, Prostigmin)
• Physostigmine
• Pyridostigmine (Mestinon, Regonol)