How does Mestinon help with myasthenia gravis?

Overview

Mestinon is a prescription medicine that can help relieve symptoms of myasthenia gravis (MG) such muscle weakness, double vision, blurred vision, drooping eyelids, loss of facial expressions, and difficulties with talking, chewing food, swallowing and breathing. There is no cure for MG, but treatments can help with symptoms.

Mestinon is used in the treatment of myasthenia gravis, an autoimmune neuromuscular disease. In MG, the immune system makes certain antibody proteins that mistakenly attack the connections between muscles and nerves. Muscles become weak and don’t work well in MG.

It helps to improve symptoms in MG by slowing the breakdown of the chemical messenger (neurotransmitter) acetylcholine at the neuromuscular junction. Our muscles need acetylcholine to work. This action helps to improve muscle strength by increasing the signals between nerves and muscles.

Mestinon is usually taken as an oral tablet or an oral syrup several times per day.

How does it work?

Mestinon affects the chemical messengers in the body that are involved in the communication between nerve impulses and muscle movement.

• Mestinon (pyridostigmine) increases levels of acetylcholine, a chemical messenger (neurotransmitter) made in our bodies.
• It prevents the acetylcholinesterase enzyme from breaking apart acetylcholine in the neuromuscular junction (between muscles and nerves), and leads to higher levels of acetylcholine.
• Greater levels of acetylcholine lead to better functioning of the nerves and muscles, leading to better strength and breathing in myasthenia gravis.

How fast does Mestinon work? How does it come at the pharmacy?

Mestinon immediate-release

Mestinon products (tablets, oral syrup) start to work within 15 minutes, have a maximum effect at about 60 to 90 minutes, and the effect usually lasts 3 to 4 hours.

Mestinon is taken several times per day to help control your symptoms. Doses of the immediate-release products may need to be taken every 4 to 8 hours. Your doctor will determine your dose and frequency based on your symptom relief.

• In general, people will take ten 60 mg tablets or ten 5 mL teaspoonfuls (60 mg/mL) daily. These doses will be spaced to provide maximum relief when maximum strength is needed.
• In some circumstances, doses can range from 1 to 6 tablets or teaspoonfuls per day, up to 25 tablets or teaspoonfuls a day.
• The oral syrup formulation is raspberry flavored and contains 5% alcohol.

Mestinon sustained-release

There is also a sustained-release formulation (180 mg Mestinon Timespan tablet). The sustained-release products last about 12 hours, but this can vary among patients. Mestinon Timespan is usually given at bed so that the patient does not need to wake up every 3 or 4 hours to take a dose of regular Mestinon.

The Mestinon Timespan tablet has a slower onset but its duration of action is about 2.5 times longer. Timespan can be used at bedtime to enable a person to sleep longer without need of medication.

In some cases, the immediate-release and sustained-release products may need to be used together for optimal results. Generics are available for all oral dosage forms (immediate / sustained release tablets, oral syrup).

Pyridostigmine injection (Regonol, Mestinon) may also be used to reverse the effect of certain neuromuscular blocking medications and can be used in military personnel who have been exposed to nerve gas. Injected pyridostigmine may be needed in patients with myasthenia gravis who cannot take medicine by mouth.

How do I know if I have myasthenia gravis?

If your doctor suspects you have myasthenia gravis, they can order special tests, such as:

• blood tests to look for antibodies
• imaging tests, such as a CT or MRI, to look at pictures inside your body
• tests to see if your muscles and nerves respond normally to electrical signals.

Your doctor will also do a physical exam and a medical and family history to help evaluate what is causing your symptoms.

This is not all the information you need to know about Mestinon (pyridostigmine bromide) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.