Dosing and uses of Mestinon, Regonol (pyridostigmine)
Adult dosage forms and strengths
inj solution
- 5mg/mL
tablet, controlled release
- 180mg
tablet
- 60mg
syrup
- 60mg/5mL (240mL)
Myasthenia Gravis
Tablets/syrup: 600 mg/day spaced to provide maximum relief
Sustained release: 180-540 mg PO qDay or q12hr; not to exceed 1.5 g/day
Reversal of Nondepolarizing Muscle Relaxants
0.1-0.25 mg/kg/dose
10-20 mg generally effective; full recovery may occur as early as <15 min but may require >30 min
To minimize side effects 0.6-1.2 mg IV atropine sulfate recommended immediately prior to pyridostigmine
Pretreatment for Soman Nerve Gas Exposure
30 mg PO q8hr beginning several hours prior to exposre
Discontinue at first sign of nerve agent exposure then begin atropine and pralidoxime
Pediatric dosage forms and strengths
inj solution
- 5mg/mL
tablet, controlled release
- 180mg
tablet
- 60mg
syrup
- 60mg/5mL (240mL)
Myasthenia Gravis
Children
- 7 mg/kg/day PO divided q4hr
- 0.05-0.15 mg/kg IV/IM q4-6hr; not to exceed 10 mg/dose
Neonates
- 5 mg PO q4-6hr
- 0.05-0.15 mg/kg IV/IM q4-6hr; not to exceed 10 mg/dose
Reversal of Nondepolarizing Muscle Relaxants
0.1-0.25 mg/kg/dose IV
Dosing range: 0.1-0.25 mg/kg/dose; full recovery may occur as early as <15 min but may require >30 min
Mestinon, Regonol (pyridostigmine) adverse (side) effects
Fewer GI effects than neostigmine
Frequency not defined
Cholinergic effects (N/V, increases peristalsis, increases salivation, urinary frequency
Weakness
Hypotension
ECG changes
Loss of consciousness
Convulsions
Drowsiness
Thrombophlebitis
Urticaria
Arrhythmia
Laryngospasm
Bradycardia
Cardiac standstill (rare)
Cholinergic crisis (rare)
Transient rash in bromide-sensitive patients
Warnings
Black Box Warning
Therapy must be administered by trained personneL
Contraindications
Hypersensitivity
Mechanical intestinal or urinary obstruction
Cautions
Caution in epilepsy, asthma, COPD, recent MI, hypertension, vagotonia, hyperthyroidism, dysrhythmia
Keep atropine and epinephrine immediately available to treat hypersensitivity reactions resulting from therapy
Injection unstable in alkaline solutions
If symptoms of excess cholinergic activity occur discontinue therapy
Anticholinesterase sensitivity may develop for brief or prolonged periods
Pregnancy and lactation
Pregnancy category: B
Lactation: Compatible
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Mestinon, Regonol (pyridostigmine)
Mechanism of action
Anticholinesterase agent which inhibits metabolism of acetylcholine by acetylcholinesterase thereby enhancing its cholinergic effects fascilitating impulses across myoneural junction
Pharmacokinetics
Half-Life: 1-2 hr (IV)
Onset: 15-30 min (PO/IM); 2-5 min (IV)
Duration: 6-8 hr (PO); 2-3 hr (IV)
Bioavailability: 10-20%
Distribution: ~19 L
Metabolism: Liver microsomal enzymes
Metabolites: 3-hydroxy-N-methylpyridinium
Total Body Clearance: 8.5-9.7 mL/min/kg
Excretion: Urine (80-90%)
Administration
IV Compatibilities
Syringe: glycopyrrolate
Y-site: heparin, hydrocortisone Na-succinate, KCl, vit B/C
Other Information
IV Administration: very slow injection
