Reply To: Mestinon Side Effects

[Community Member]

I read through the thread and unless I missed it, nobody mentioned Mestinon Timespan 180mg. It is an extended release version that is good for about 12 hours. I don’t know offhand what the equivalent dose is for the regular Mestinon. My family member who has MG has struggled with the rollercoaster effects of the regular Mestinon which has a half life of 4 hours (which would require taking it 6 times a day to avoid the worst of the rollercoaster), and found the extended release version has been very helpful. Muscle fasciculation (spasms/twitching) can be a sign of too much Mestinon at once, lowering the dosage and taking it more often helps even out the rollercoaster ride, or switching to ER. Regular and ER can even be taken together if the ER dosage isn’t exactly what is needed, the neuro can help calculate a hybrid dosage. Regular tablets can also be split to reduce dosage (ER cannot be split).

Note that Mestinon is extremely hydrophilic, meaning it sucks up water from the air like crazy. I don’t know if that makes it less effective over time, another question for the neuro (or pharmacist), I’ve seen tablets blow up to twice their size in the span of a month. So in humid climates, one may want to purchase extra little desiccant packs and add them to opened bottles, avoid opening bottles until ready to start using them (they seem to behave when the bottle remains sealed), and if possible try to avoid the 3-month subscriptions that pharma and insurance wants to push on us.

Mestinon magnifies the power of the neurotransmitter acetylcholine. While the muscles affected by MG have one type of ACTH receptor (nicotinic), the autonomic nervous system such as digestion use a slightly different ACTH receptor (muscarinic), and Mestinon can amplify both. Family member was also suffering gastroparesis and Mestinon helped greatly with that. Others who still have normal digestion and other normal ANS behavior might have side effects from the Mestinon.

As for treatment, everything I’ve read (being a caregiver) ranks a progression of treatment options:
Mestinon
Prednisone
DMARDs
Biologics
IVIg, Plasmapharesis
Thymectomy

Mestinon is a band-aid. It improves the communication signal at the neuromuscular junction to reduce weakness, but it does nothing about the auto-antibodies attacking the NMJ. (MG is an autoimmune disease.) The immune system remains out of control and the patient remains hostage to the whims of the immune system.

Prednisone is a start at controlling the immune system and the production of those auto-antibodies. It is not a good long term solution but can be very helpful while other treatment options are sorted out.

DMARDs are drugs that modify the immune system and try to reduce its production of auto-antibodies. CellCept is one, Methotrexate another, and Azathioprine another.

Biologics such as Rituxan are “smart bombs” that are designed to interfere with specific steps of auto-antibody production or attack, mileage will vary here too.

IVIg adds other people’s antibodies, I don’t think doctors are quite sure how it helps but it may have something to do with getting one’s own auto-antibodies under control. Plasmapharesis cleans antibodies out of the bloodstream, including the auto-antibodies, the fewer that remain, the less mischief they can create.

Thymectomy is the nuclear option. The thymus gland is the master programmer of the immune system. It’s supposed to program the adaptive immune system in childhood, then retire at puberty. For some (like my family member), it became faulty and did not retire, one only knows what that bloated mess was generating in the way of autoimmune cells.

I am amazed at the speed of research into MG, and somewhat disheartened that all this information is so slow to percolate down to the neuros practicing in the field.