Schedule H

Intravenous (IV), Intramuscular (IM)

• Injection: 10 mg/mL (1 mL ampoule) — as edrophonium chloride

• Note: Limited commercial availability; primarily sourced through hospital pharmacy imports or specialty distributors

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Diagnosis of Myasthenia Gravis (Edrophonium/Tensilon Test)

Diagnostic Protocol (Adults):

Step Dose Observation

Step 1: Test dose 2 mg IV push over 15–30 seconds Observe for 45–60 seconds for adverse reactions (bradycardia, bronchospasm)

Step 2: If no adverse reaction 8 mg IV (given as 3 mg, then 5 mg at 30-second intervals) Observe for improvement in muscle strength within 30–60 seconds

Alternative single-dose method 10 mg IV total (2 mg test + 8 mg if tolerated) Same observation

Parameter Details

Starting dose 2 mg IV (test dose)

Titration Additional 8 mg IV in increments if test dose tolerated

Usual maintenance dose Not applicable (single diagnostic use)

Maximum dose 10 mg IV per test

IM Route (when IV access difficult):

Parameter Details

Starting dose 10 mg IM

Titration Not applicable

Usual maintenance dose Not applicable

Maximum dose 10 mg IM

Clinical Notes:

• Onset of action: IV 30–60 seconds; IM 2–10 minutes

• Duration of effect: 5–10 minutes

• Keep IV atropine (0.6–1.2 mg) drawn and ready before test

• Positive test: Transient improvement in muscle strength (resolution of ptosis, improved grip strength, diplopia improvement)

• Perform in monitored setting with resuscitation equipment available

• Can differentiate myasthenic crisis (improvement) from cholinergic crisis (worsening or no change)

1. Differentiation of Myasthenic Crisis vs Cholinergic Crisis

Parameter Details

Starting dose 1–2 mg IV

Titration Not applicable

Usual maintenance dose Not applicable

Maximum dose 2 mg for differentiation

Interpretation:

• Improvement in weakness → Myasthenic crisis (underdosing of anticholinesterase)

• Worsening or no change → Cholinergic crisis (overdosing of anticholinesterase)

Clinical Notes:

• Use lower dose for crisis differentiation to avoid precipitating severe cholinergic crisis

• Have atropine and ventilatory support immediately available

• Perform only in ICU or monitored setting

1. Reversal of Non-depolarising Neuromuscular Blockade (Adjunctive Use)

Parameter Details

Starting dose 0.5 mg/kg IV (usual adult dose: 35–70 mg)

Titration Not applicable (single dose)

Usual maintenance dose Not applicable

Maximum dose 1 mg/kg or 70 mg

Anticholinergic Co-administration (mandatory):

• Atropine: 0.007–0.014 mg/kg IV, OR

• Glycopyrrolate: 0.007–0.01 mg/kg IV

Clinical Notes:

• Administer slowly over 45–60 seconds

• Onset: 30–60 seconds; Duration: 5–10 minutes

• Short duration limits clinical utility; neostigmine preferred for routine reversal

• Use only when very short-duration reversal needed

• Monitor for recurarisation due to short duration

Secondary Indications — Adults (Off-label)

Indication Notes

No established off-label indications in Indian practice Longer-acting agents (neostigmine, pyridostigmine) preferred for therapeutic anticholinesterase use

PAEDIATRIC DOSING (Specialist Only)

Primary Indications (Approved / Standard in India)

1. Diagnosis of Myasthenia Gravis (Edrophonium Test)

Age/Weight Group Test Dose Additional Dose Maximum Total

Infants (<10 kg) 0.1 mg IV 0.4 mg IV if tolerated 0.5 mg

Children 10–34 kg 1 mg IV Up to 4 mg IV in 1 mg increments 5 mg

Children ≥34 kg 2 mg IV Up to 8 mg IV in increments 10 mg

Alternative Weight-based Dosing:

Parameter Details

Starting dose 0.04 mg/kg IV (test dose)

Titration 0.16 mg/kg IV if test dose tolerated (given in increments)

Usual maintenance dose Not applicable

Maximum dose 0.2 mg/kg or 10 mg total (whichever is less)

IM Route:

Parameter Details

Starting dose 0.2 mg/kg IM

Titration Not applicable

Maximum dose 10 mg IM

Clinical Notes:

• Perform only under trained paediatric neurologist supervision

• Atropine (0.01–0.02 mg/kg) must be immediately available

• Continuous cardiac monitoring mandatory

• Monitor closely for bradycardia, bronchospasm, excessive secretions

• Have resuscitation equipment ready

Secondary Indications — Paediatrics (Off-label)

Indication Notes

Reversal of non-depolarising neuromuscular blockade Not preferred in paediatrics; neostigmine is standard agent

Age Restriction Statement:

• Not recommended in children below 2 years except under strict specialist supervision in tertiary care neurology/neuromuscular centres

• Neonatal use only in exceptional circumstances with full ICU support

• No specific dose adjustment required for diagnostic use

• Short duration of action limits accumulation risk

• Use with caution in severe renal impairment (eGFR <30 mL/min/1.73m²) due to potential reduced clearance

• Monitor more closely for cholinergic effects in renal impairment

• Known hypersensitivity to edrophonium chloride or quaternary ammonium compounds

• Mechanical gastrointestinal obstruction

• Mechanical urinary tract obstruction

• Cardiac conduction defects (second or third-degree AV block) without pacemaker

• Sick sinus syndrome without pacemaker

• Concurrent use with depolarising neuromuscular blockers (e.g., suxamethonium)

• Bronchial asthma or COPD (risk of bronchospasm; benefit must outweigh risk)

• Bradyarrhythmias (always have atropine ready)

• Recent myocardial infarction

• Epilepsy (cholinergic stimulation may lower seizure threshold)

• Peptic ulcer disease

• Hyperthyroidism

• Parkinsonism

• Vagotonia

• Elderly patients with cardiovascular disease

• Patients on beta-blockers or digoxin

• Conditions requiring prolonged neuromuscular block reversal (short duration may be inadequate)

Parameter Recommendation

Risk category Limited human data; use only when clearly indicated

Preferred alternatives Edrophonium is actually preferred for brief diagnostic use due to short half-life (vs. longer-acting agents)

When may be used When MG diagnosis is essential and benefit outweighs risk; single diagnostic use acceptable

Monitoring Maternal heart rate; blood pressure; fetal heart rate monitoring; uterine activity

Parameter Recommendation

Compatibility Probably compatible for single diagnostic use

Drug levels in milk Expected to be very low (short half-life, quaternary ammonium structure limits transfer)

Preferred alternatives No alternative for diagnostic purpose; single-use poses minimal risk

Infant monitoring Not routinely required for single diagnostic dose; observe for any GI disturbance if concerned

Parameter Recommendation

Starting dose Use lowest test dose (1–2 mg IV)

Titration Slower incremental dosing with longer observation periods between doses

Special risks Increased sensitivity to cholinergic effects; higher risk of severe bradycardia, hypotension, syncope; often have underlying cardiac disease; reduced cardiac reserve

Precautions Pre-treatment with atropine 0.4 mg IV may be considered in patients with high vagal tone or baseline bradycardia; continuous ECG monitoring essential

Interacting Drug Effect Recommendation

Depolarising muscle relaxants (suxamethonium) Prolonged Phase I block; may enhance depolarising effect Avoid concurrent use; ensure suxamethonium has fully dissipated

Other cholinesterase inhibitors (neostigmine, pyridostigmine) Additive cholinergic toxicity; risk of cholinergic crisis Avoid concurrent use; can confound diagnostic test

Beta-blockers Additive bradycardia; risk of severe bradycardia or asystole Pre-treat with atropine if beta-blocker cannot be withheld; continuous cardiac monitoring

Digoxin Enhanced AV nodal block; risk of complete heart block Monitor ECG closely; pre-treatment with atropine advised

Interacting Drug Effect Recommendation

Anticholinergics (atropine, glycopyrrolate) Block muscarinic effects Used intentionally to prevent adverse muscarinic effects; may partially mask diagnostic response

Corticosteroids (in MG patients) May improve muscle strength independently Note if patient on steroids; may affect test interpretation

Aminoglycoside antibiotics May impair neuromuscular transmission May affect test interpretation; note in history

Calcium channel blockers Additive effect on cardiac conduction Monitor heart rate and rhythm

Magnesium salts May potentiate neuromuscular blockade Note in history; may affect test interpretation

• Increased salivation

• Lacrimation

• Sweating

• Nausea

• Abdominal cramping

• Muscle fasciculations

• Mild bradycardia

• Urinary urgency

• Miosis

• Diarrhoea

Adverse Effect Clinical Action

Cholinergic crisis (severe bradycardia, bronchospasm, excessive secretions, hypotension, muscle weakness) Discontinue immediately; IV atropine 0.6–1.2 mg (repeat as needed); supportive care

Severe bradycardia / Asystole IV atropine; cardiac resuscitation if needed

Bronchospasm Discontinue; bronchodilators; atropine; oxygen

Hypotension with syncope Discontinue; IV fluids; supine positioning; atropine if bradycardia present

Seizures (rare) Discontinue; standard seizure management

Cardiac arrest Full resuscitation protocol

Phase Parameters

Pre-test (Baseline) ECG; heart rate; blood pressure; baseline muscle strength assessment (ptosis, grip strength, diplopia); confirm atropine drawn and ready; resuscitation equipment available

During administration Continuous cardiac monitoring (ECG, HR, BP); observe muscle strength changes; SpO₂; watch for signs of cholinergic excess

Post-dose (5–15 minutes) Continue cardiac monitoring until baseline HR restored; observe for rebound weakness; respiratory status; document test result

Brand Name Manufacturer Availability

Tensilon (Imported) Limited; primarily through hospital pharmacy import

Edrophonium Injection Generic Limited; specialty distributors

Notes:

• Commercial availability is limited in India

• Often sourced through hospital pharmacy special imports

• No fixed-dose combinations available

• Some centres may not have ready access; plan ahead for elective diagnostic testing

• Not included in NLEM 2022

• Not under NPPA price control

• Primarily hospital supply; may not be available in retail pharmacies

• Price may vary significantly based on import source

1. Always have atropine ready — Draw up atropine 0.6–1.2 mg IV before starting the test; life-threatening bradycardia or bronchospasm can occur within seconds.

1. Test dose is essential — Never give full 10 mg without first assessing response to 2 mg; this identifies patients at high risk for severe cholinergic reactions.

1. Short duration is the key feature — Effects last only 5–10 minutes; this limits therapeutic utility but makes it ideal for diagnostic purposes; neostigmine preferred for NMB reversal and treatment.

1. Document baseline weakness objectively — Use quantifiable measures (ptosis in mm, grip strength, diplopia pattern) before test to allow meaningful comparison.

1. Differentiate crisis types cautiously — In suspected crisis, use smaller dose (1–2 mg) and observe carefully; worsening suggests cholinergic crisis (stop anticholinesterase therapy), improvement suggests myasthenic crisis (increase therapy).

1. Limited availability in India — Plan ahead; confirm availability with hospital pharmacy before scheduling elective diagnostic tests; neostigmine or ice-pack test may be alternatives when edrophonium unavailable.

edrophonium; tensilon test; myasthenia gravis diagnosis; cholinesterase inhibitor; short-acting anticholinesterase; diagnostic agent; neurology; neuromuscular junction; atropine-required; limited-availability

RxIndia v1.0 — 01 Feb 2026

• CDSCO import and approval database

• Indian Pharmacopoeia / National Formulary of India

• API Textbook of Medicine — Myasthenia Gravis chapter

• AIIMS Neurology Department protocols

• Goodman & Gilman's The Pharmacological Basis of Therapeutics

• Harrison's Principles of Internal Medicine — Myasthenia Gravis

• IAP Guidelines — Paediatric neuromuscular disorders

• Indian tertiary care hospital protocols (AIIMS, NIMHANS, CMC Vellore)