Classifications: anticholinergic agent; cholinesterase inhibitor; Therapeutic: cholinesterase inhibitor
Pregnancy Category: C
60 mg/5 mL syrup; 60 mg tablet; 180 mg extended release tablet; 5 mg/mL injection
Analog of neostigmine; indirect-acting cholinergic that inhibits cholinesterase activity. Facilitates transmission of impulses
across myoneural junctions by blocking destruction of acetylcholine.
Direct stimulant action on voluntary muscle fibers and possibly on autonomic ganglia and CNS neurons. Produces increased
tone in skeletal muscles.
Myasthenia gravis and as an antagonist to nondepolarizing skeletal muscle relaxants (e.g., curariform drugs).
Hypersensitivity to anticholinesterase agents or to bromides. Mechanical obstruction of urinary or intestinal tract; bradycardia,
hypotension; pregnancy (category C).
Bronchial asthma; epilepsy; renal impairment; vagotonia; hyperthyroidism; peptic ulcer; cardiac dysrhythmias.
Route & Dosage
Adult: PO 60 mg1.5 g/d spaced according to response of individual patient; sustained release: 180540 mg 12 times/d at intervals of at least 6 h IM/IV Approximately 1/30 of PO dose
Child: PO 7 mg/kg/d divided into 56 doses
Neonates: PO 5 mg q46h IM/IV 0.050.15 mg/kg q46h
Reversal of Muscle Relaxants
Adult: IV 1020 mg immediately preceded by IV atropine
- Give with food or fluid.
- Ensure that sustained release form is not chewed or crushed. Must be swallowed whole.
- Note: A syrup is available. Some patients may not like it because it is sweet; try to make it more palatable by giving it over
ice chips. The syrup formulation contains 5% alcohol.
- Note: Parenteral dose is about 1/30 the oral adult dose.
- Give deep IM into a large muscle.
PREPARE: Direct: Give undiluted. Do NOT add to IV solutions.
ADMINISTER: Direct: Give at a rate of 0.5 mg over 1 min for myasthenia gravis; 5 mg over 1 min for reversal of muscle relaxants.
- Store at 15°30° C (59°86° F). Protect from light and moisture.
Adverse Effects (≥1%)Skin:
Acneiform rash. Hematologic:
Thrombophlebitis (following IV administration
). GI: Nausea, vomiting, diarrhea. Special Senses: Miosis. Body as a Whole: Excessive salivation and sweating,
weakness, fasciculation. Respiratory:
Increased bronchial secretion, bronchoconstriction. CV:
Interactions Drug: Atropine nondepolarizing muscle relaxants
antagonize effects of pyridostigmine.
Poorly from GI tract. Onset:
3045 min PO; 15 min IM; 25 min IV
36 h. Distribution:
Crosses placenta. Metabolism:
In liver and in serum
by cholinesterases. Elimination:
Assessment & Drug Effects
- Report increasing muscular weakness, cramps, or fasciculations. Failure of patient to show improvement may reflect either
underdosage or overdosage.
- Observe patient closely if atropine is used to abolish GI adverse effects or other muscarinic adverse effects because it
may mask signs of overdosage (cholinergic crisis): Increasing muscle weakness, which through involvement of respiratory
muscles can lead to death.
- Monitor vital signs frequently, especially respiratory rate.
- Observe for signs of cholinergic reactions (see Appendix F), particularly when drug is administered IV.
- Observe neonates of myasthenic mothers, who have received pyridostigmine, closely for difficulty in breathing, swallowing,
- Observe patient continuously when used as muscle relaxant antagonist. Airway and respiratory assistance must be maintained
until full recovery of voluntary respiration and neuromuscular transmission is assured. Complete recovery usually occurs
within 30 min.
Patient & Family Education
- Be aware that duration of drug action may vary with physical and emotional stress, as well as with severity of disease.
- Report onset of rash to physician. Drug may be discontinued.
- Sustained release tablets may become mottled in appearance; this does not affect their potency.