Pyridostigmine Bromide

Registered South African indications: 

• Myasthenia gravis

Contraindications

• Hypersensitivity to the active ingredient or any of its excipients
• Mechanical gastrointestinal obstruction
• Urinary obstruction

Cautions

• Pregnancy
• Breastfeeding
• Renal impairment
• Elderly
• Obstructive respiratory diseases
• Arrhythmia
• Recent coronary occlusion
• Hypotension
• Vagotonia
• Peptic ulcer
• Epilepsy
• Parkinsonism
• Hyperthyroidism
• Post-thymectomy
• Galactose intolerance
• Lapp lactase deficiency
• Glucose-galactose malabsorption

Forms avail. in SA and covered in this monograph: tab

Myasthenia gravis

• Oral (tab): Initial: 60mg, 8hrly; Usual range: 60-80mg, 6-8hrly; Max: 720mg/24hrs

The usual duration of action is 3-4hrs in the daytime but a longer effect (6hrs) is often obtained with a dose taken at bedtime

Stomach cramps, nausea, vomiting and diarrhoea often limits higher dosing schedules

Paralytic ileus
Post-operative urinary retention

• Oral (tab): 60-240mg/day, in divided doses

Paed. forms avail. in SA and covered in this monograph: tab

Myasthenia gravis

• Oral (tab): 7mg/kg/day, in 5-6 divided doses

The usual duration of action is 3-4hrs in the daytime but a longer effect (6hrs) is often obtained with a dose taken at bedtime

Pregnancy 

• Caution
• The safety of pyridostigmine bromide during pregnancy has not been established
• Although the possible hazards to mother and child must be weighed against the potential benefits in every case, experience with pyridostigmine bromide in pregnant patients with myasthenia gravis has revealed no untoward effect of the drug on the course of pregnancy
• Pyridostigmine bromide crosses the placenta barrier. Excessive doses of pyridostigmine bromide should be avoided; the newborn child should be monitored for possible effects
• Intravenous application of pyridostigmine bromide can induce contraction of the uterus (especially in the last period of pregnancy)
• As the severity of myasthenia gravis often fluctuates considerably, particular care is required to avoid cholinergic crisis, due to overdosage of the drug, but otherwise management is no different from that in non-pregnant patients

Breastfeeding 

• Caution
• The safety of pyridostigmine bromide during breastfeeding has not been established
• Observations indicate that only negligible amounts of pyridostigmine bromide are excreted in breast milk; nevertheless, due regard should be paid to possible effects on the breastfeeding infant

Renal Impairment 

• eGFR > 30mL/min/1.73m2: No dose adjustment needed 
• eGFR < 29mL/min/1.73m²: Caution; dose adjustment recommended
  Initiate dose with 10-20 mg, and slowly up-titrate according to the clinical response

Hepatic Impairment 

• No dose adjustment recommended

Elderly

• No dose adjustment recommended

Porphyria Information

• Probably not porphyrinogenic (PNP)

Drugs in Sport

• Permitted - No warning

Cardiovascular Disorders

• Arrhythmia
• Syncope
• Hypotension  

Respiratory Disorders

• Increased bronchial secretion combined with bronchoconstriction

Gastrointestinal Disorders 

• Nausea and vomiting
• Diarrhoea
• Abdominal cramps
• Gastrointestinal hypermotility
• Salivary hypersecretion

Genitourinary Disorders

• Urinary urgency

Musculoskeletal Disorders

• Increased muscle weakness fasciculation
• Tremors
• Muscle cramps
• Muscle hypotonia  

Skin and Subcutaneous Tissue Disorders 

• Rash
• Hyperhydrosis

Sensory Disorders

• Miosis
• Increased lacrimation
• Accommodation disorders

• Immunosuppressive agents
• Methylcellulose
• Antimuscarinics
• Muscle relaxants
• Aminoglycoside antibiotics
• Local anaesthetics
• General anaesthetics
• Antiarrhythmic agents
• Agents that interfere with neuromuscular transmission

None routine 

Pyridostigmine bromide is an antagonist to cholinesterase. It inhibits destruction of acetylcholine by acetylcholinesterase which facilitates transmission of impulses across neuromuscular junctions. It has a slower onset and longer duration of action than neostigmine. Because of this, it is usually much better tolerated by myasthenic patients in whom the longer action is also an advantage.

Tablet 10mg

• Mestinon (Mylan) originator

Tablet 60mg

• Mestinon (Mylan) originator