Neostigmine is an anticholinesterase drug that is used for most commonly to stimulate muscle control.
Its action is to competitively inhibits acetylcholine (ACh) from attaching to acetylcholinestase (AChE) binding sites, where ACh is normally broken down by hydrolysis. This allows ACh to persist for a longer period of time enhancing transmission across neuromuscular junctions.
Neostigmine is a prescription drug and can only be obtained from a veterinarian or by prescription from a veterinarian.
This drug is not approved for use in animals by the Food and Drug Administration but it is prescribed legally by veterinarians as an extra-label drug.
Brand Names and Other Names This drug is registered for use in humans only.
Human formulations: Prostigmine® (ICN) and Neostigmine Methylsulfate (various generic manufacturers/suppliers)
Veterinary formulations: None
Uses of Neostigmine Reversal of the effects of non-depolarizing neuromuscular blocking agents
Symptomatic control in myasthenia gravis
Prevention and treatment of post-operative urinary retention (if mechanical blockage has been eliminated as a possible cause)
Stimulation of intestinal smooth muscle (increased peristalsis)
Reversal of the physiological effects some snake venoms
Treatment of ivermectin poisoning
Precautions and Side Effects While generally safe and effective when prescribed by a veterinarian, neostigmine can cause side effects in some animals.
Neostigmine should not be used in animals with known hypersensitivity or allergy to the drug.
Neostigmine should not be used in pregnant animals.
In addition, it should be avoided when there is intestinal or urinary tract obstruction or peritonitis.
Neostigmine should be used with caution in patients with bronchial asthma (cats), epilepsy, bradycardia, enhanced vagal tone (some brachycephalic dogs), hyperthyroidism (esp. cats), cardiac arrhythmias, and gastric ulcers.
Neostigmine may interact with other medications. Consult with your veterinarian to determine if other drugs your pet is receiving could interact with neostigmine. Such interactions may include: If neostigmine is to be given to patients receiving drugs with weak neuromuscular blocking activity (e.g. aminoglycosides, some antiarrhythmics and anesthetic drugs), its dose may have to be increased.
Corticosteroids may decrease neostigmine's anticholinesterase activity.
Neostigmine may prolong neuromuscular blockade produced by depolarizing muscle relaxants (e.g. succinylcholine).
How Neostigmine is Supplied Neostigmine is available as an injection in a 1:1000 concentration. It is supplied in 1 mL amps and 10 mL vials.
Dosing Information Medication should never be administered without first consulting your veterinarian.
The dosage prescribed may vary depending on the reason for prescribing.
The duration of administration depends on the condition being treated, response to the medication and the development of any adverse effects. Be certain to complete the prescription unless specifically directed by your veterinarian. Even if your pet feels better, the entire treatment plan should be completed to prevent relapse.
In dogs and cats with myasthenia gravis, the usual dose is 0.02 mg per pound (0.04 mg/kg) every 6 hours intramuscularly.
When used as a smooth muscle stimulant, the usual dose is 0.02 to 0.025 mg per pound (0.04 – 0.05 mg/kg) subcutaneously or intramuscularly.
When used for the reversal of a non-depolarizing neuromuscular block, the dose of neostigmine required for reversal depends on the degree of block present. Because of this, the dose of neostigmine varies widely so it often given in incremental doses 0.005 to 0.01 mg per pound (0.01 - 0.02 mg/kg), while monitoring for effect.
NOTE: *When neostigmine is administered by intravenous injection, atropine may be given several minutes beforehand to counteract unwanted muscarinic side effects such as bradycardia, increased secretions, and bronchoconstriction.