Mestinon (Pyridostigmine Bromide)
Pyridostigmine is used to improve muscle strength in patients with a certain muscle disease (myasthenia gravis). It works by preventing the breakdown of a certain natural substance (acetylcholine) in your body. Acetylcholine is needed for normal muscle function. Mestinon or any insulin products (vials, pens, cartridges) are not steroids.
Ensure you let your doctor know of any medications you are currently on, including insulin. Your doctor may be able to prescribe you a particular insulin that is compatible with Mestinon (ie, insulin isophane)
Mestinon is an antagonist to cholinesterase, the enzyme which normally destroys acetylcholine. The action of Mestinon can briefly be described, therefore, as the potentiation of naturally occurring acetylcholine. Mestinon has a more prolonged action than Prostigmin (neostigmine) although it is somewhat slower to take effect (generally taking 30 – 60 minutes). Because it has a weaker “muscarinic” action than Prostigmin, it is usually much better tolerated by myasthenic patients in whom the longer action is also an advantage.
Mestinon is also available in SR
Warnings and Precautions
Do not take this medication if you have an allergy to Pyridostigmine or any ingredients in this Mestinon.
Speak to your doctor about any of your past or existing medical conditions, especially if you have: asthma or COPD, intestinal/stomach blockage, kidney or lung disease, urinary blockage, slow/irregular heartbeat or diabetes.
Consult your doctor if you are pregnant or breastfeeding.
Do not use this medication if you have bladder or bowel obstruction.
Since this medication can cause blurred vision, do not drive or operate any heavy machinery after taking it. Please do not drink alcohol after taking Mestinon as it can increase specific side effects of Pyridostigmine.
This medication is not approved to be taken by anyone under the age of 18.
The most common side effects with Mestinon include blurred vision, cough, diarrhea, nausea, sweating, abdominal pain, rash, muscle cramps, and vomiting.
Severe side effects with the medication include: loss of movement in any part of your body, slurred speech, vision problems, extreme muscle weakness, weak or shallow breathing and worsening or no improvement of myasthenia graves. If you suffer from any serious side effects please get in touch with your pharmacist, doctor or visit a health facility immediately.
Each person may react differently to a treatment. If you think this medication may be causing side effects (including those described here, or others), talk to your doctor or pharmacist. He or she can help you to determine whether or not the medication is the source of the problem.
This medication is typically used only once a day. However, your doctor or pharmacist may have suggested a different schedule that is more appropriate for you. Take it regularly and continuously to maintain its beneficial effects.
Important: Follow the instructions on the label. Do not use more of this product, or more often, than prescribed. This medication should not be chewed or crushed.
Atropine antagonizes the muscarinic effects of pyridostigmine, and this interaction may be utilized to counteract the effects of pyridostigmine. (See Overdose Section)
Pyridostigmine bromide does not antagonize, and in fact, may prolong the phase I block of depolarizing muscle relaxants such as succinylcholine or decamethonium.
Certain antibiotics, especially neomycin, streptomycin, and kanamycin, have a mild but definite nondepolarizing blocking action which may accentuate neuromuscular block. These antibiotics should be used in the myasthenic patient only where indicated, and then a careful adjustment should be made of adjunctive anticholinesterase dosage.
Local and some general anesthetics, antiarrhythmic agents, and other drugs that interfere with neuromuscular transmission should be used cautiously, if at all, in patients with myasthenia gravis; the dose of pyridostigmine bromide may have to be increased accordingly.
In severe myasthenia gravis, neostigmine has been combined with pyridostigmine to provide the benefits of short and long-term activity; because of the possibility of reduced intestinal motility and increased toxicity, this combination should be used only under strict medical supervision.
The dosage, route, and frequency of administration depend on the requirements and clinical response of the patients. The dosage schedule should be adjusted for each patient and changed as the need arises. Dosage requirements in patients with myasthenia gravis may vary from day to day, according to the patient’s remissions and exacerbations of the disease and the physical and emotional stress. More significant portions of the label daily dose may be given when the patient is more prone to fatigue (afternoon, mealtimes, etc.).
Although the failure of patients to show clinical improvement may reflect under dosage, it can also be indicative of overdosage. As is true of all cholinergic drugs, overdosage of Mestinon (pyridostigmine) may result in cholinergic crisis, a state characterized by increasing muscle weakness which, through the involvement of the muscles of respiration, may lead to death. Myasthenic crisis due to an increase in the severity of the disease is also accompanied by extreme muscle weakness and thus may be difficult to distinguish from the cholinergic crisis on a symptomatic basis. Such differentiation is significant since increases in doses of Mestinon (pyridostigmine) or other drugs of this class in the presence of cholinergic crisis or a refractory or “insensitive” state could have grave consequences.
As with most medications, this product should be stored at room temperature. Store it in a secure location where it will not be exposed to excessive heat, moisture, or direct sunlight. Make sure that any leftover portion is disposed of safely.
Keep all your medications out of the reach of children and pets and return any unused or expired medications to the pharmacy for proper disposal.