indication

For the treatment of myasthenia gravis.

pharmacology

Pyridostigmine is a parasympathomimetic and a reversible cholinesterase inhibitor. Since it is a quaternary amine, it is poorly absorbed in the gut and doesn't cross the blood-brain barrier. Pyridostigmine has a slightly longer duration of action than NEOSTIGMINE. It is used in the treatment of myasthenia gravis and to reverse the actions of muscle relaxants.

mechanism of action

Pyridostigmine inhibits acetylcholinesterase in the synaptic cleft by competing with acetylcholine for attachment to acetylcholinesterase, thus slowing down the hydrolysis of acetylcholine, and thereby increases efficiency of cholinergic transmission in the neuromuscular junction and prolonges the effects of acetylcholine.

biotransformation

Hydrolysis by cholinesterases and by liver.

absorption

Poorly absorbed from the GI tract with an oral bioavailability of 7.6 +/- 2.4%.

half life

3 hours following oral administration.

drug interactions

Betamethasone: The corticosteroid, betamethasone, may decrease the effect of the anticholinesterase, pyridostigmine.

Corticotropin: The corticosteroid, corticotropin, may decrease the effect of the anticholinesterase, pyridostigmine.

Cortisone acetate: The corticosteroid, cortisone acetate, may decrease the effect of the anticholinesterase, pyridostigmine.

Dexamethasone: The corticosteroid, dexamethasone, may decrease the effect of the anticholinesterase, pyridostigmine.

Fludrocortisone: The corticosteroid, fludrocortisone, may decrease the effect of the anticholinesterase, pyridostigmine.

Hydrocortisone: The corticosteroid, hydrocortisone, may decrease the effect of the anticholinesterase, pyridostigmine.

Methylprednisolone: The corticosteroid, methylprednisolone, may decrease the effect of the anticholinesterase, pyridostigmine.

Paramethasone: The corticosteroid, paramethasone, may decrease the effect of the anticholinesterase, pyridostigmine.

Prednisolone: The corticosteroid, prednisolone, may decrease the effect of the anticholinesterase, pyridostigmine.

Prednisone: The corticosteroid, prednisone, may decrease the effect of the anticholinesterase, pyridostigmine.

Triamcinolone: The corticosteroid, triamcinolone, may decrease the effect of the anticholinesterase, pyridostigmine.