Physostigmine


Generic Medicine Info
Indications and Dosage
Intramuscular, Intravenous
Reversal of anticholinergic effect
Adult: Initial: 0.5-2 mg via slow IV (1 mg/minute) or IM inj. May repeat every 10-30 minutes until desired response is achieved. Dose reduction, dosing interruption, or discontinuation may be required according to individual safety or tolerability (refer to detailed product guideline).
Child: Initial: 0.02 mg/kg via slow IV (0.5 mg/minute) or IM inj. May repeat every 5-10 minutes until desired response is achieved. Max: 2 mg.
Contraindications
CV disease, diabetes, asthma, gangrene; gastrointestinal and genitourinary obstruction, or any vagotonic state. Concomitant use with choline esters (e.g. methacholine, bethanechol) and depolarizing neuromuscular-blocking agents (e.g. succinylcholine).
Special Precautions
Patient with seizure or bradycardia. Concomitant use with epileptogenic drugs. Children. Pregnancy and lactation.
Adverse Reactions
Significant: Arrhythmias, seizure (increased risk with rapid administration), cholinergic effects (e.g. nausea, vomiting, urinary incontinence, salivation, defecation), hypersensitivity reactions.
Cardiac disorders: Bradycardia (if administered rapidly).
Monitoring Parameters
Monitor ECG and vital signs. Assess for signs of cholinergic crisis during treatment.
Overdosage
Symptoms: Nausea, vomiting, diarrhoea, excessive salivation and sweating, miosis, bradycardia or tachycardia, hypotension or hypertension, severe muscle weakness, paralysis, confusion, seizures, coma and death (as a result of respiratory paralysis and/or pulmonary oedema). Management: Administer atropine sulfate 2-4 mg (adult); 1 mg (children) every 3-10 minutes until muscarinic effects are controlled.
Drug Interactions
May enhance the cholinergic effects of cholinergic agonists (e.g. bethanechol, methacholine). May increase the serum concentration of succinylcholine. May increase risk of seizures with epileptogenic drugs.
Action
Description: Physostigmine is a reversible anticholinesterase derived from Calabar bean. It inhibits the action of acetylcholinesterase thereby prolonging the central and peripheral effects of acetylcholine.
Onset: Within 3-8 minutes.
Duration: Approx 45-60 minutes.
Pharmacokinetics:
Absorption: Readily absorbed from the gastrointestinal tract, subcutaneous tissues, and mucous membranes.
Distribution: Distributed throughout the body. Crosses the blood-brain barrier.
Metabolism: Metabolised via hydrolysis by cholinesterases.
Excretion: Via urine (small amount). Elimination half-life: 1-2 hours.
Chemical Structure

Chemical Structure Image
Physostigmine

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 5983, Physostigmine. https://pubchem.ncbi.nlm.nih.gov/compound/Physostigmine. Accessed Aug. 26, 2021.

Storage
Store between 20-25°C.
MIMS Class
Antidotes & Detoxifying Agents
ATC Classification
V03AB19 - physostigmine ; Belongs to the class of antidotes. Used in the management of noxious gases poisoning.
References
Anon. Physostigmine Salicylate. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 14/07/2021.

Anon. Physostigmine. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 14/07/2021.

Buckingham R (ed). Physostigmine. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 14/07/2021.

Physostigmine Salicylate (Akorn, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 14/07/2021.

Disclaimer: This information is independently developed by MIMS based on Physostigmine from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 MIMS. All rights reserved. Powered by MIMS.com
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