Neostigmine

Indications

Neostigmine is used for: Myasthenia gravis, Paralytic ileus; Post-op urinary retention, Reversal of nondepolarising neuromuscular blockade

Adult Dose

Parenteral As metilsulfate Myasthenia gravis Adult: 0.5-2.5 mg by IM or SC inj, doses are given at intervals according to response up to a total daily dose of 5-20 mg. Paralytic ileus and postoperative urinary retention Adult: 0.5-2.5 mg by SC or IM inj, as required. Reversal of neuromuscular blockade Adult: 0.03-0.07 mg/kg by inj over 60 sec, as required. Not to exceed 0.07 mg/kg or a cumulative total of 5 mg, whichever dose is less Inject by slow IV over at least 1 minute Oral Myasthenia gravis Adult: As neostigmine bromide: 15-30 mg. Doses are given at intervals according to response up to a usual total daily dose of 75-300 mg.

Child Dose

Parenteral As metilsulfate Myasthenia gravis Child: <12 yr 0.2-0.5 mg, repeated at suitable intervals throughout the day. Paralytic ileus and postoperative urinary retention Child: 0.125-1 mg by SC or IM inj. Intravenous Reversal of neuromuscular blockade Child: 0.05-0.07 mg/kg by inj over 60 sec, as required. Oral Myasthenia gravis As neostigmine bromide: Child: <6 yr Initially, 7.5 mg; 6-12 yr Initially, 15 mg. Doses are adjusted according to response up to a usual total daily dose of 15-90 mg. Intramuscular Neonatal myasthenia gravis Child: Initially, 0.1 mg, followed by 0.05-0.25 mg or 0.03 mg/kg 2-4 hrly.

Renal Dose

Renal impairment: Dose adjustment may be required. Renal impairment: Continuous renal replacement therapy (CRRT): 50% of normal dose. CrCl (ml/min) Dosage Recommendation <10 25% of normal dose. 10-50 50% of normal dose.

Administration

Contra Indications

Mechanical GI or urinary tract obstruction, peritonitis.

Precautions

Patient w/ bronchial asthma, CV disorders (e.g. bradycardia, recent MI, hypotension), peptic ulcer disease, vagotonia, epilepsy, parkinsonism, hyperthyroidism. Patient who underwent recent intestinal or bladder surgery. Renal impairment. Childn. Pregnancy and lactation. Monitoring Parameters Monitor ECG, BP and heart rate esp w/ IV use. Lactation: Unknown if distributed in human breast milk; use caution

Pregnancy-Lactation

Interactions

May reduce effects of anticholinergics. May increase effects of cholinergic agonists. Increased risk of bradycardia with digoxin, diltiazem, verapamil or beta-blockers without intrinsic sympathomimetic activity. Increased muscle weakness and decreased response to anticholinesterases with corticosteroids. May increase effects of depolarising neuromuscular blockers. Effects may be antagonised by drugs with neuromuscular blocking activity e.g. aminoglycosides, clindamycin, colistin, cyclopropane, halogenated inhalational anaesthetics. Effects may be reduced by quinine, chloroquine, hydroxychloroquine, quinidine, procainamide, propafenone, lithium, beta-blockers. Possible additive toxicity with ophthalmic use of anticholinesterases e.g. ecothiopate.

Adverse Effects

Side effects of Neostigmine : Allergic: Allergic reactions and anaphylaxis Neurologic: Dizziness, convulsions, loss of consciousness, drowsiness, headache, dysarthria, miosis and visual changes Cardiovascular: Cardiac arrhythmias (including bradycardia, tachycardia, A-V block and nodal rhythm) and nonspecific EKG changes have been reported, as well as cardiac arrest, syncope and hypotension (predominantly with parenteral dosage form) Respiratory: Increased oral, pharyngeal and bronchial secretions, and dyspnea; respiratory depression, respiratory arrest and bronchospasm have been reported following the use of the injectable form Dermatologic: Rash and urticaria Gastrointestinal: Nausea, emesis, flatulence, and increased peristalsis and salivation Genitourinary: Urinary frequency Musculoskeletal: Muscle cramps and spasms, arthralgia Miscellaneous: Diaphoresis, flushing and weaknes Potentially Fatal: Anaphylaxis.

Mechanism of Action

Neostigmine reversibly inhibits acetylcholinesterase and thus potentiates the nicotinic and muscarinic effects of acetylcholine. This facilitates the transmission of impulses across myoneural junction.