Pyridostigmine SR Eye Medicine: Uses, Brands & Dosage

Pyridostigmine SR is a sustained-release tablet used for the long-duration control of ocular and generalised myasthenia gravis.

Drug class	Acetylcholinesterase Inhibitor
Type	Single
Forms	Tablet (sustained-release)
Common strength	180 mg
Common Indian brands	Mestinon SR, Distinon
Prescription status	Prescription

What Pyridostigmine SR is used for

Pyridostigmine SR is a medication primarily used in the field of Neuro-Ophthalmology. It is prescribed for:

Long-duration control of ocular myasthenia gravis: This is a condition where the muscles around the eyes become weak and tire easily, leading to symptoms like drooping eyelids (ptosis) or double vision (diplopia).
Long-duration control of generalised myasthenia gravis: This is a broader form of the condition where muscle weakness can affect various parts of the body, including those involved in breathing, swallowing, and limb movement.

By providing sustained control, Pyridostigmine SR helps manage the symptoms of myasthenia gravis over a longer period, improving muscle strength and reducing fatigue.

How it works

Pyridostigmine SR belongs to a class of medicines called Acetylcholinesterase Inhibitors. To understand how it works, let’s briefly look at how our muscles move.

Our brain sends signals to our muscles through nerves. At the junction where a nerve meets a muscle (called the neuromuscular junction), a chemical messenger called acetylcholine is released. Acetylcholine attaches to receptors on the muscle, causing it to contract and move. After it has done its job, an enzyme called acetylcholinesterase breaks down acetylcholine, allowing the muscle to relax.

In myasthenia gravis, there’s a problem with the acetylcholine receptors on the muscle, meaning acetylcholine cannot effectively stimulate the muscle. This leads to muscle weakness and fatigue.

Pyridostigmine SR works by inhibiting (blocking) the action of acetylcholinesterase. By doing so, it prevents the rapid breakdown of acetylcholine. This means more acetylcholine remains available at the neuromuscular junction for a longer time, allowing it to have a greater chance of stimulating the available receptors on the muscle. This prolonged action of acetylcholine helps to improve muscle strength and reduce the symptoms of myasthenia gravis, providing steadier symptom control.

Because Pyridostigmine SR is a ‘sustained-release’ form, it releases the medicine slowly over time, ensuring a more consistent level of medication in your body throughout the day or night, depending on when you take it.

How it’s used

Pyridostigmine SR is a tablet that comes in a sustained-release form. This means the medicine is released slowly into your body over an extended period. This design is specifically for long-duration control of your condition.

Here’s some general guidance on how to use Pyridostigmine SR:

Dosing: This medicine is typically taken once or twice a day. The exact frequency and timing will be determined by your ophthalmologist based on your specific condition and how you respond to the treatment.
Swallowing the tablet: Pyridostigmine SR tablets should be swallowed whole with water. Do not crush, chew, or break the tablet. Breaking the tablet can alter the sustained-release mechanism and may lead to an incorrect dose being absorbed too quickly or too slowly.
Consistency: Try to take your medicine at the same time(s) each day as prescribed by your doctor. This helps maintain a consistent level of the medication in your body, which is important for effective symptom control.
With or without food: Your doctor will advise you if you should take this medicine with food or on an empty stomach. Follow their instructions carefully.
Missed dose: If you miss a dose, take it as soon as you remember, unless it is almost time for your next scheduled dose. In that case, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are unsure, please contact your doctor or pharmacist for advice.
Duration of treatment: Pyridostigmine SR is often used for long-term management of myasthenia gravis. Do not stop taking this medicine without consulting your ophthalmologist, even if you feel better. Stopping abruptly can cause your symptoms to return or worsen.

Remember, this is a prescription medicine, and you must follow your ophthalmologist’s instructions precisely for the best results and to ensure your safety.

Always follow your ophthalmologist’s exact instructions.

Brands available in India

Mestinon SR
Distinon

Brand availability and pricing vary; confirm with your pharmacist.

Good to know

Prescription eye medicine — use only as directed by a qualified ophthalmologist. This page is for general education and is not a substitute for professional medical advice, diagnosis or a prescription. Do not self-medicate or reuse an old prescription.

Precautions & side effects

While Pyridostigmine SR is an effective medication for myasthenia gravis, it’s important to be aware of certain precautions and to use it exactly as prescribed by your ophthalmologist.

Prescription Medicine: Pyridostigmine SR is a prescription-only medicine. It must be used only as directed by a qualified ophthalmologist. This page is for general education and is not a substitute for professional medical advice, diagnosis, or a prescription. Do not self-medicate or reuse an old prescription.
Sustained-Release Form: This medicine is in a sustained-release (SR) form, which means it releases the active ingredient slowly over time. This is designed to provide long-lasting control of your symptoms, offering overnight or daytime cover as needed. It is crucial not to crush, chew, or break these tablets, as this can disrupt the sustained-release mechanism and lead to an improper dose being absorbed.
Potential Side Effects: Like all medicines, Pyridostigmine SR can have side effects, although not everyone experiences them. Common side effects can include nausea, vomiting, diarrhoea, abdominal cramps, increased saliva production, increased sweating, and muscle cramps or twitching. If any of these side effects are severe or persistent, please inform your doctor.
Interactions: Inform your ophthalmologist about all other medications you are currently taking, including over-the-counter drugs, herbal supplements, and vitamins. Some medicines can interact with Pyridostigmine SR, potentially affecting its effectiveness or increasing the risk of side effects.
Medical Conditions: Discuss your complete medical history with your doctor, especially if you have any existing heart conditions, asthma, chronic obstructive pulmonary disease (COPD), stomach ulcers, kidney problems, or epilepsy. Your doctor will assess if Pyridostigmine SR is suitable for you.
Driving and Operating Machinery: Myasthenia gravis itself can affect vision and muscle control. While Pyridostigmine SR aims to improve these symptoms, some side effects might temporarily impair your ability to drive or operate machinery. Exercise caution and follow your doctor’s advice regarding these activities.
Pregnancy and Breastfeeding: If you are pregnant, planning to become pregnant, or breastfeeding, discuss this with your ophthalmologist before starting or continuing Pyridostigmine SR. Your doctor will weigh the potential benefits against any risks.
Regular Follow-ups: Regular check-ups with your ophthalmologist are essential to monitor your condition, assess the effectiveness of the treatment, and adjust the dosage if necessary.

Always communicate openly with your healthcare team about any concerns or changes you experience while taking Pyridostigmine SR.

Understanding Myasthenia Gravis and Your Eyes

Myasthenia gravis is a chronic autoimmune condition that causes weakness in the voluntary muscles of the body. In an autoimmune condition, your body’s immune system mistakenly attacks its own healthy tissues. In myasthenia gravis, the immune system attacks the connections between your nerves and muscles, specifically the receptors for a chemical messenger called acetylcholine. This makes it harder for your muscles to receive signals from your nerves, leading to muscle weakness and fatigue.

When myasthenia gravis affects the muscles around your eyes, it’s called ocular myasthenia gravis. Common symptoms include drooping eyelids (ptosis), where one or both eyelids may sag, and double vision (diplopia), where you see two images of a single object. These symptoms can fluctuate throughout the day, often worsening with activity and improving with rest. In some cases, the weakness can spread to other muscles in the body, affecting speech, swallowing, breathing, and limb movement; this is known as generalised myasthenia gravis. Understanding your condition is the first step towards managing it effectively, and your ophthalmologist at Pristine Eye Hospitals is here to guide you through every stage.

General Advice for Taking Your Medicine

Taking your medicine correctly is vital for managing myasthenia gravis and achieving the best possible results. Pyridostigmine SR is a tablet, and while it’s not an eye drop, general principles of medication adherence are crucial. Always follow the specific instructions given by your ophthalmologist regarding the dose, timing, and duration of your Pyridostigmine SR. Since it is a sustained-release tablet, remember not to crush, chew, or break it; swallow it whole with water. This ensures the medicine is released slowly and steadily into your body, providing consistent symptom control. Try to take your medicine at the same time each day to maintain stable levels in your system. If you miss a dose, take it as soon as you remember, unless it’s almost time for your next dose. In that case, skip the missed dose and continue your regular schedule. Never take a double dose. Keep all your medicines out of reach of children and pets, and store them in a cool, dry place away from direct sunlight and moisture, as indicated on the packaging.

When to Seek Help and General Eye Care

While Pyridostigmine SR helps manage the symptoms of myasthenia gravis, it’s important to remain vigilant and know when to contact your healthcare provider. If you experience any new or worsening symptoms of myasthenia gravis, such as increased muscle weakness, difficulty breathing, swallowing, or speaking, seek immediate medical attention. Also, if you notice any severe or unusual side effects from your medication, such as severe stomach pain, persistent diarrhoea, excessive sweating, or muscle cramps, inform your ophthalmologist promptly. Regular follow-up appointments with your doctor are essential to monitor your condition, assess the effectiveness of your treatment, and make any necessary adjustments to your medication. Beyond your specific treatment, maintaining good general eye hygiene is always recommended. Wash your hands thoroughly before touching your eyes, and avoid rubbing your eyes excessively. If you wear contact lenses, ensure they are cleaned and stored properly. If you experience any new eye pain, redness, discharge, or sudden changes in vision, contact Pristine Eye Hospitals without delay. Your health and well-being are our priority, and our team is always ready to provide expert care and support.

Frequently asked questions

What is Pyridostigmine SR used for?

Pyridostigmine SR is a medicine used for the long-duration control of ocular myasthenia gravis (muscle weakness affecting the eyes) and generalised myasthenia gravis (muscle weakness affecting various parts of the body).

How does Pyridostigmine SR work?

Pyridostigmine SR works by prolonging the action of a chemical messenger called acetylcholine at the nerve-muscle junction. This helps to improve muscle strength and provides steadier symptom control for patients with myasthenia gravis.

What are the common brands of Pyridostigmine SR available in India?

In India, common brands for Pyridostigmine SR include Mestinon SR and Distinon.

How should I take Pyridostigmine SR?

Pyridostigmine SR is a sustained-release tablet, typically taken once or twice a day as prescribed by your ophthalmologist. It should be swallowed whole with water; do not crush, chew, or break the tablet.

Do I need a prescription for Pyridostigmine SR?

Yes, Pyridostigmine SR is a prescription-only medicine. You must use it only as directed by a qualified ophthalmologist.

What are the key precautions I should be aware of when taking Pyridostigmine SR?

Always take Pyridostigmine SR exactly as prescribed and do not crush or chew the sustained-release tablet. Inform your doctor about all other medications you are taking and any existing medical conditions. Be aware of potential side effects like nausea or muscle cramps, and contact your doctor if they are severe or persistent. Regular follow-ups with your ophthalmologist are crucial.

References

Medically reviewed by Dr. C Jagadesh Reddy, Chief Surgeon: Cornea, Cataract and Refractive Surgery — last reviewed 2026-07-28.

This page is for general education only and is not a substitute for professional medical advice, diagnosis or treatment. Never self-medicate or reuse an old prescription. Always consult a qualified ophthalmologist before starting, changing or stopping any eye medicine.