Pyridostigmine

Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.

Pyridostigmine (brand name Mestinon) — Anti-myasthenic; Cholinesterase inhibitor.

Identification

• Therapeutic class: Anti-myasthenic.
• Pharmacologic class: Cholinesterase inhibitor.

Pharmacology

• Mechanism of action: Raises acetylcholine at the neuromuscular junction to improve muscle strength.
• Onset / peak / duration: Onset 15 to 30 minutes; duration 3 to 6 hours; ER longer.
• Half-life / therapeutic level: Short; dose by symptoms.

Clinical use

• Indications: Myasthenia gravis.
• Usual dose, route, frequency: PO several times daily timed to activity; IV in hospital.
• Maximum dose / adjustments: Titrate to strength; reduce in renal impairment.

Safety

• Contraindications: GI or urinary obstruction, hypersensitivity.
• Black box warning: None.
• Interactions: Anticholinergics oppose effect, neuromuscular blockers, other cholinergics.
• Pregnancy / lactation: Used when needed.
• High-alert: No.

Adverse effects

• Common side effects: Abdominal cramps, increased salivation, sweating, diarrhea.
• Serious effects to report: Cholinergic crisis (excess salivation, weakness, respiratory difficulty) versus myasthenic crisis (under-dosing).
• Antidote / reversal: Atropine for cholinergic crisis.

Nursing process

• Assessment before administration: Muscle strength, respiratory status, timing to meals and activity.
• Interventions during therapy: Time doses before meals to aid chewing and swallowing; distinguish cholinergic from myasthenic crisis.
• Monitor: Muscle strength, respiratory status, GI effects.
• Evaluation / expected outcome: Improved strength.

Patient teaching

• Patient teaching: Take on schedule; report increasing weakness or breathing trouble.
• Notify provider if: Worsening weakness, breathing difficulty, excessive secretions.
• Administration tips: Time before meals and activity.