Pyridostigmine

What is pyridostigmine?

Pyridostigmine belongs to the so-called cholinesterase inhibitors. These are substances that inhibit an enzyme called cholinesterase. Cholinesterase is responsible for breaking down the neurotransmitter acetylcholine. Acetylcholine is important for the transmission of nerve impulses to the muscles. When cholinesterase is inhibited, more acetylcholine remains in the gap between the nerves and the muscles and can therefore increase muscle contraction.

How does pyridostigmine work in dogs with myasthenia gravis?

Myasthenia gravis is an autoimmune disease in which the immune system produces antibodies against the acetylcholine receptors. These are the docking sites for acetylcholine on the muscle cells. The antibodies block or destroy the receptors so that less acetylcholine can bind to them. This leads to reduced muscle strength and endurance.

Pyridostigmine increases the amount of acetylcholine in the synaptic cleft and thus improves the excitability of the muscles. This enables dogs with myasthenia gravis to walk, eat, breathe and perform other activities better.

How is pyridostigmine used?

Pyridostigmine is administered orally in the form of tablets or syrup. The dosage depends on the severity of the disease, the weight of the dog and the individual reaction. The dose often needs to be adjusted to achieve an optimal effect. Treatment with pyridostigmine is usually necessary for life.

What are the advantages of pyridostigmine?

Pyridostigmine has the advantage that it works relatively quickly and significantly improves the quality of life of dogs with myasthenia gravis. It can also be given in combination with other drugs such as corticosteroids or immunosuppressants to suppress the immune system and reduce the formation of antibodies.

What are the disadvantages of pyridostigmine?

Pyridostigmine also has some disadvantages that you should be aware of. For one thing, it can cause side effects such as diarrhea, vomiting, salivation, tremors or cramps. These mainly occur if the dose is too high or if the dog is sensitive to the medication. In this case, you should contact your vet and adjust the dose or discontinue the medication.

On the other hand, pyridostigmine can trigger a so-called cholinergic crisis. This is a life-threatening condition in which the parasympathetic nervous system is overstimulated. This manifests itself in symptoms such as increased salivation, vomiting, diarrhea, sweating, slow heartbeat, low blood pressure or shortness of breath. A cholinergic crisis requires immediate veterinary treatment with an antidote called atropine.