What is the preferred oral acetylcholinesterase inhibitor for myasthenia gravis?

Pyridostigmine is often preferred to neostigmine for myasthenia gravis for three reasons:

(1) The onset of the effect of oral pyridostigmine (approximately 45 minutes) is faster than that for neostigmine (approximately 4 hours). The speedier onset allows for more precise adjustment of the dosing schedule around daily living activities to ensure as much muscle function as possible when required.

(2) The half-life of pyridostigmine (approximately 90 to 110 minutes) is longer than that for neostigmine (approximately 50 to 90 minutes). The difference is not great, but when the patient has to take the drug multiple times in a day, it is an advantage that 3 or 4 times per day is often sufficient with pyridostigmine.

(2) Pyridostigmine is about four times less potent than neostigmine. That is right, being less potent is an advantage because it is easier to titrate the dose to a level that controls the motor symptoms without causing too many adverse effects. This is especially important in the early stages of the disease when the motor symptoms are less pronounced.