II. Indications

  1. Pretreatment before Nerve Agent Exposure (Soman)
  2. Myasthenia Gravis
    1. Provides symptomatic relief, esp. extremity weakness and bulbar symptoms
    2. Less effective on Ptosis and Diplopia
    3. Unlikely to benefit myasthenia crisis with Respiratory Failure and may interfere with respiratory management

III. Physiology

  1. Pyridostigmine is an Anticholinesterase
  2. Results in increased Cholinergic effects

IV. Pharmacokinetics: Nerve Agent Exposure

  1. Significantly enhances post-exposure antidote for Soman
  2. Does not enhance antidote for other Nerve Agents
  3. Raises Soman LD50 by several fold

V. Dosing: Nerve Agent Exposure

  1. Pyridostigmine 30 mg PO every 8 hours before exposure

VI. Dosing: Myasthena Gravis

  1. Child: 0.5 to 1 mg/kg every 4-6 hours (maximum 7 mg/kg/day divided every 4 to 6 hours)
  2. Adult
    1. Starting Dose: 30 mg three times daily
    2. Typical Dose: 60 to 90 mg every 4 to 6 hours while awake
    3. Maximum Dose: 120 mg every 4 hours while awake
  3. Pharmacokinetics
    1. Onset: 15-30 minutes
    2. Peaks: 2 hours
    3. Duration: 3-4 hours

VII. Adverse Effects

  1. Risk of Cholinergic Toxicity
  2. Risk of worsening myasthenia crisis (due to mucous plugging, bronchorrhea)

VIII. Precautions: Nerve Agent Exposure

  1. Pyridostigmine does not protect against exposure
  2. Nerve Agent Exposures must be treated with Antidote

IX. References

  1. (1998) USAMRICD Chemical Casualties Handbook, p. 58-9

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Cost: Medications

pyridostigmine (on 5/17/2017 at Medicaid.Gov Survey of pharmacy drug pricing)
PYRIDOSTIGMINE BR 60 MG TABLET Generic $0.51 each
PYRIDOSTIGMINE ER 180 MG TAB Generic $10.93 each
mestinon (on 10/13/2016 at Medicaid.Gov Survey of pharmacy drug pricing)
MESTINON 180 MG TIMESPAN Generic $10.93 each

Ontology: Pyridostigmine (C0034261)

Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D011729
SnomedCT 373344003, 59953007
LNC LP17869-6, MTHU024724
English PYRIDOSTIGMINE, pyridostigmine, Pyridostigmine (product), Pyridostigmine (substance), Pyridostigmine
Spanish piridostigmina (producto), piridostigmina (sustancia), piridostigmina