Formulary
Pyridostigmine bromide: Indications, Dosing, Side Effects and Interactions
They prolong the action of acetylcholine by inhibiting the action of the enzyme acetylcholinesterase.
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Pyridostigmine bromide: Indications, Dosing, Side Effects and Interactions
They prolong the action of acetylcholine by inhibiting the action of the enzyme acetylcholinesterase.
Drug action
They prolong the action of acetylcholine by inhibiting the action of the enzyme acetylcholinesterase. Drug action For pyridostigmine bromide Pyridostigmine bromide has weaker muscarinic action than neostigmine.
Indications and dose
**Myasthenia gravis**
- **Adult** (By Mouth): 30-120 mg, doses to be given at suitable intervals throughout day; usual dose 0.3-1.2 g daily in divided doses, it is inadvisable to exceed a total daily dose of 450 mg in order to avoid acetylcholine receptor down-regulation; patients requiring doses exceeding 450 mg daily will usually require input from a specialised neuromuscular service. Immunosuppressant therapy is usually considered if the dose of pyridostigmine exceeds 360 mg daily.
**Myasthenia gravis for pyridostigmine bromide**
- **Neonate** (By mouth): Initially 0.5-1 mg/kg every 4-6 hours, then increased if necessary up to 1.2 mg/kg every 4 hours, dose can be increased every 3 to 4 days, or more often during inpatient treatment with monitoring for side-effects; give 30-60 minutes before feeds.
- **Child 1 month-11 years** (By mouth): Initially 0.5-1 mg/kg every 4-6 hours, then increased if necessary up to 1.2 mg/kg every 4 hours, dose can be increased every 3 to 4 days, or more often during inpatient treatment with monitoring for side-effects; usual maximum dose 60 mg every 4 hours.
- **Child 12-17 years** (By mouth): 30-90 mg every 4-6 hours, consider immunosuppressant therapy if total daily dose exceeds 360 mg, down-regulation of acetylcholine receptors possible if total daily dose exceeds 450 mg.
Cautions
Arrhythmias; asthma (extreme caution); atropine or other antidote to muscarinic effects may be necessary (particularly when neostigmine is given by injection) but not given routinely because it may mask signs of overdosage; bradycardia; epilepsy; hyperthyroidism; hypotension; parkinsonism; peptic ulceration; recent myocardial infarction; vagotonia Cautions, further information Elderly Screening Tool of Older Persons' potentially inappropriate Prescriptions (STOPP) criteria to aid medication reviews (see Prescribing in the elderly for information). Potentially inappropriate: in patients with a known history of persistent bradycardia (heart rate less than 60 beats per minute), heart block, or recurrent unexplained syncope, or concurrent treatment with drugs that reduce heart rate (risk of cardiac conduction failure, syncope, and injury).
Contraindications
Intestinal obstruction; urinary obstruction
Side effects
Frequency not known Abdominal cramps; diarrhoea; excessive tearing; hypersalivation; nausea; vomiting Overdose Signs of overdosage include bronchoconstriction, increased bronchial secretions, lacrimation, excessive sweating, involuntary defaecation, involuntary micturition, miosis, nystagmus, bradycardia, heart block, arrhythmias, hypotension, agitation, excessive dreaming, and weakness eventually leading to fasciculation and paralysis. Side-effects For pyridostigmine bromide Frequency not known Gastrointestinal hypermotility; muscle cramps; rash
Interactions
**Other interactions (6):**
- Immunosuppressant drugs The requirement for pyridostigmine bromide could be decreased by concomitant use with corticosteroids or immunosuppressant drugs.
- Nethertheless, a new addition of corticosteroids may initially aggravate the symptoms of myasthenia gravis.
- Antimuscarinics Atropine and hyoscine antagonise the muscarinic effects of pyridostigmine bromide and the slower gastro-intestinal motility caused by these drugs may affect the absorption of...
- Muscle Relaxants Pyridostigmine antagonises the effect of non-depolarising muscle relaxants (e.g.
- Pyridostigmine may prolong the effect of depolarising muscle relaxants (e.g.
- Others Aminoglycoside antibiotics, local and some general anesthetics, antiarrhythmic agents, and other drugs that interfere with neuromuscular transmission may interact with pyridostigmine bromide.
Pregnancy
Manufacturer advises use only if potential benefit outweighs risk.
Breast feeding
Amount probably too small to be harmful.
Renal impairment
Dose adjustments Consider dose reduction (excreted renally). M
Medicinal forms
Tablet,Tablet,Solution
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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