neostigmine bromide

neostigmine bromide

[nē′ōstig′mēn]

a reversible acetylcholinesterase inhibitor.

indications It is prescribed in situations in which it is desirable to potentiate the effects of neuronally released acetylcholine, such as in the treatment of myasthenia gravis and postoperative urinary retention, and to reverse the effects of nondepolarizing neuromuscular blockers.

contraindications Bowel obstruction, urinary tract infection, or known hypersensitivity to this drug or to other bromides prohibits its use. Initial dosages should be administered only in settings equipped for cardiopulmonary resuscitation, and ephinephrine and atropine should be available.

adverse effects Overdosage causes cholinergic crisis with widespread muscle weakness and paralysis, including the diaphragm, which can cause severe respiratory depression. Excessive salivation and lacrimation, intestinal cramps, urinary urgency, and convulsions are among other adverse effects.

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neostigmine bromide

Prostigmin

Pharmacologic class: Anticholinesterase

Therapeutic class: Muscle stimulant

Pregnancy risk category C

Action

Inhibits enzyme acetylcholinesterase, leading to increased acetylcholine concentration at synapse and prolonged acetylcholine effects. Exerts direct cholinomimetic effect on skeletal muscle.

Availability

Injection (methylsulfate): 2 mg/ml, 1 mg/ml, 0.5 mg/ml, 0.25 mg/ml

Tablets (bromide): 15 mg

⊘Indications and dosages

➣ Myasthenia gravis

Adults: 15 mg/day P.O.; may increase p.r.n. up to 375 mg/day; average dosage is 150 mg/day. Or 1 ml of 1:2,000 solution (0.5 mg) subcutaneously or I.M. based on response and tolerance.

➣ Postoperative abdominal distention and bladder atony

Adults: 0.5 to 1 mg I.M. or subcutaneously. If given for urinary retention and no response occurs within 1 hour, catheterize patient as ordered and repeat dose q 3 hours for five doses.

➣ Antidote for nondepolarizing neuromuscular blockers

Adults: 0.5 to 2.5 mg I.V.; repeat p.r.n. up to 5 mg. Precede initial dose with 0.6 to 1.2 mg atropine sulfate I.V., as ordered.

Contraindications

• Hypersensitivity to cholinergics or bromide
• Mechanical obstruction of GI or urinary tract
• Peritonitis

Precautions

Use cautiously in:
• asthma, peptic ulcer, bradycardia, arrhythmias, recent coronary occlusion, vagotonia, hyperthyroidism, seizure disorder
• pregnant or breastfeeding patients.

Administration

☞ Before giving, ensure that atropine sulfate is available to treat cholinergic crisis.
• Know that atropine may be combined with usual neostigmine dose to decrease risk of adverse reactions.
• Give oral form 1 hour before or 2 hours after a meal.
• Administer I.V. dose undiluted directly into vein or I.V. line. Give 0.5-mg dose slowly over 1 minute.
☞ Keep resuscitation equipment nearby.

Route	Onset	Peak	Duration
P.O.	45-75 min	1-2 hr	2-4 hr
I.V.	4-8 min	1-2 hr	2-4 hr
I.M., subcut.	20-30 min	1-2 hr	2-4 hr

Adverse reactions

CNS: dizziness, headache, drowsiness, asthenia, loss of consciousness

CV: hypotension, tachycardia, bradycardia, atrioventricular (AV) block , cardiac arrest

EENT: vision changes, lacrimation, miosis

GI: nausea, vomiting, diarrhea, abdominal cramping, flatulence, increased peristalsis

GU: urinary frequency

Musculoskeletal: muscle cramps, spasms, and fasciculations; joint pain

Respiratory: dyspnea, bronchospasm, respiratory depression, respiratory arrest, laryngospasm

Skin: rash, urticaria, flushing

Other: anaphylaxis

Interactions

Drug-drug. Aminoglycosides, anticholinergics, atropine, corticosteroids, local and general anesthetics: reversal of anticholinergic effects

Cholinergics: additive toxicity

Kanamycin, neomycin, streptomycin: increased neuromuscular blockade

Succinylcholine: potentiation of neuromuscular blockade, prolonged respiratory depression

Patient monitoring

☞ Monitor vital signs. Assess patient for hypotension, bradycardia or tachycardia, AV block, and evidence of impending cardiac arrest.
• Evaluate respiratory and neurologic status.

Patient teaching

• Instruct patient to take tablets 1 hour before or 2 hours after meals.
☞ Tell patient drug may alter his respiratory and cardiac status. Teach him to recognize and immediately report warning signs.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, vision, muscle function, and alertness.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs mentioned above.