Treatment of Myasthenia Gravis
Each Sugar coated tablet contains: Pyridostigmine bromide 60 mg.
Pyridostigmine inhibits the destruction of acetylcholine by cholinesterase and thereby permits free transmission of nerve impulses across the neuromuscular junction.
Pyridostigmine is an analog of neostigmine, but differs from it in certain clinically significant respects; for example, Pyridostigmine is characterized by a longer duration of action and fewer gastrointestinal side effects.
Pyridostigmine bromide is poorly absorbed from the gastrointestinal tract. It undergoes hydrolysis by cholinesterases and is also metabolised in the liver.
Pyridostigmine is excreted mainly in the urine as unchanged drug and metabolites. Pyridostigmine crosses the placenta and very small amounts are distributed into breast milk. Penetration into the CNS is poor.
Indications & Usage
Pystinon is useful for the treatment of myasthenia gravis.
Pyridostigmine is contraindicated in mechanical intestinal or urinary obstruction, and particular caution should be used in its administration to patients with bronchial asthma. Care should be observed in the use of atropine for counteracting side effects.
The Side effects of Pyridostigmine are most commonly related to overdosage and generally are of two varieties, muscarinic and nicotinic. Among those in the former group are nausea, vomiting, diarrhea, abdominal cramps, increased peristalsis, increased salivation, increased bronchial secretions, miosis and diaphoresis.
Nicotinic side effects are comprised chiefly of muscle cramps, fasciculation and weakness.
Muscarinic side effects can usually be counteracted by atropine, but for reasons shown in the preceding section the expedient is not without danger.
As with any compound containing the bromide radical, a skin rash may be seen in an occasional patient. Such reactions, usually subside promptly upon discontinuance of the medication.
Warnings & Precautions
Pyridostigmine is mainly excreted unchanged by the kidney. Therefore, lower doses may be required in patients with renal disease and treatment should be based on titration of drug dosage to effect.
Pediatric Use: Safety and effectiveness in pediatric patients have not been established.
Warnings: Although failure of patients to show clinical improvement may reflect underdosage, it can also be indicative of overdosage. As is true of all cholinergic drugs, overdosage of Pyridostigmine may result in cholinergic crisis, a state characterized by increasing muscle weakness which, through 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 cholinergic crisis on a symptomatic basis. Such differentiation is extremely important, since increases in doses of Pyridostigmine or other drugs of this class in the presence of cholinergic crisis or of a refractory or insensitive state could have grave consequences.
Atropine may also be used to abolish or obtund gastrointestinal side effects or other muscarinic reactions, but such use, by masking signs of overdosage, can lead to inadvertent induction of cholinergic crisis.
Usage in Pregnancy: The safety of Pyridostigmine during pregnancy or lactation in humans has not been established. Therefore, use of Pyridostigmine in women who may become pregnant requires weighing the drug’s potential benefits against its possible hazards to mother and child.
Dosage & Administration
The size and frequency of the dosage must be adjusted to the needs of the individual patient.
The average dose is ten 60 mg tablets daily of Pystinon, spaced to provide maximum relief when maximum strength is needed in severe cases as many as 25 tablets a day may be required while in mild cases 1-6 tablets a day may suffice.
Pack contains 20 or 1000 tablets.
Patient Information Leaflet
Pystinon – Arabic information leaflet
Pystinon – English information leaflet
بيستينون 60 ملغ أقراص مغلفة – بيريدوستيغمين
Produced by: Alexandria Co. for Pharmaceuticals & Chemical Industries – Alex. -Egypt. ATC code: N07AA02