Schedule H

Intravenous (IV), Intramuscular (IM)

• Injection: 50 mg/mL in 2 mL ampoule (100 mg per ampoule)

• Injection: 50 mg/mL in 10 mL vial (500 mg per vial — for infusion use)

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Rapid Sequence Intubation (RSI)

(Emergency airway management, aspiration risk, difficult airway)

Intravenous Route (Preferred):

Parameter Details

Starting dose 1–1.5 mg/kg IV bolus (rapid injection)

Titration Not applicable — single bolus administration

Usual maintenance dose Not applicable — single-dose use only

Maximum dose 2 mg/kg per dose

Intramuscular Route (When IV Access Unavailable):

Parameter Details

Starting dose 3–4 mg/kg IM (deltoid or vastus lateralis)

Titration Not applicable

Usual maintenance dose Not applicable

Maximum dose 150 mg per IM dose

Clinical Notes:

Ensure airway control capability and resuscitation equipment immediately available

Preoxygenation mandatory before administration

Consider atropine pretreatment (0.01–0.02 mg/kg IV) to prevent bradycardia, especially with repeat dosing

NOT for routine intubation when rocuronium available and urgency permits

1. Short-Term Neuromuscular Blockade for Brief Surgical Procedures

Parameter Details

Starting dose 0.3–0.6 mg/kg IV bolus

Titration Additional 0.3–0.6 mg/kg boluses if required (rare)

Usual maintenance dose Not recommended — use non-depolarising agent for prolonged paralysis

Maximum dose Cumulative dose 2.5 mg/kg

Clinical Notes:

Avoid repeated boluses — risk of Phase II (desensitisation) block

Transition to non-depolarising neuromuscular blocker (rocuronium, vecuronium) for procedures >10 minutes

Monitor neuromuscular function with peripheral nerve stimulator if repeated dosing required

1. Electroconvulsive Therapy (ECT)

(Modification of motor seizure activity)

Parameter Details

Starting dose 0.5–1 mg/kg IV bolus

Titration Not applicable

Usual maintenance dose Single dose per session

Maximum dose 1.5 mg/kg per session

Clinical Notes:

Administer after induction agent (typically propofol or thiopental)

Ensure adequate paralysis before electrical stimulus

Manual ventilation required until spontaneous respiration returns

Secondary Indications — Adults Only (Off-label)

Not applicable — No established off-label indications. Succinylcholine use is restricted to short-term neuromuscular blockade only due to safety profile.

PAEDIATRIC DOSING (Specialist Only)

Primary Indications

1. Rapid Sequence Intubation (RSI)

Intravenous Route:

Neonates (<1 month) 2 mg/kg IV Not applicable 3 mg/kg

Infants (1–12 months) 2 mg/kg IV Not applicable 3 mg/kg

Children (1–12 years) 1–2 mg/kg IV Not applicable 2 mg/kg

Adolescents (>12 years) 1–1.5 mg/kg IV Not applicable 2 mg/kg

Intramuscular Route (No IV Access):

All paediatric ages 4–5 mg/kg IM 150 mg per dose

Clinical Notes:

• Higher dose requirements in neonates and infants due to larger volume of distribution

• Atropine pretreatment MANDATORY in children <5 years: 0.01–0.02 mg/kg IV (minimum 0.1 mg) to prevent severe bradycardia

• Neonates and infants: Use preservative-free formulation if available

Monitoring:

• Continuous ECG — bradycardia common in paediatric population

• SpO₂ and end-tidal CO₂

• Serum potassium if risk factors for hyperkalaemia present

• Watch for masseter muscle rigidity — early sign of malignant hyperthermia

Secondary Indications — Paediatric (Off-label)

Not applicable — No established off-label paediatric indications.

⚠️ FDA/international guidance discourages routine use in children and adolescents for elective procedures due to risk of rhabdomyolysis and hyperkalaemic cardiac arrest in undiagnosed myopathies. Use only when RSI is specifically indicated. Rocuronium with sugammadex reversal is preferred alternative where available.

⚠️ Not recommended below 1 month of age except under specialist supervision (Paediatric Anaesthesiologist/Neonatologist) due to immature pseudocholinesterase activity and increased hyperkalaemia risk.

Caution: Patients with chronic kidney disease (especially those on dialysis) may have baseline hyperkalaemia — succinylcholine causes additional potassium release (0.5–1 mEq/L). Monitor serum potassium and ECG. Avoid if pre-existing hyperkalaemia (K⁺ >5.5 mEq/L).

Note: Succinylcholine is hydrolysed by plasma pseudocholinesterase (butyrylcholinesterase), which is synthesised in the liver.

• Personal or family history of malignant hyperthermia

• Known or suspected pseudocholinesterase (plasma cholinesterase) deficiency

• History of hyperkalaemia or conditions predisposing to acute hyperkalaemia:

• Burns >24–48 hours old (risk persists up to 2 years post-burn)

• Crush injuries or major trauma >24 hours old

• Denervation injuries (spinal cord injury, stroke) >48–72 hours old

• Prolonged immobilisation or bed rest >72 hours

• Upper motor neuron lesions >24–48 hours duration

• Known neuromuscular disorders:

• Duchenne muscular dystrophy

• Becker muscular dystrophy

• Other myopathies (including undiagnosed myopathy — particularly concerning in male children)

• Myotonia congenita

• Myasthenic syndrome

• Hypersensitivity to succinylcholine

• Penetrating eye injury (relative — increased intraocular pressure may cause extrusion of globe contents)

• Burns <24 hours old — may still use cautiously if RSI urgently needed

• Severe sepsis or prolonged ICU admission — upregulation of extrajunctional acetylcholine receptors increases hyperkalaemia risk

• Increased intracranial pressure — fasciculations may transiently elevate ICP

• Increased intraocular pressure — avoid in open globe injuries unless life-threatening airway emergency

• Increased intragastric pressure — fasciculations may increase aspiration risk

• Renal failure with hyperkalaemia — monitor potassium closely

• Elderly or malnourished patients — may have reduced pseudocholinesterase activity

• Pregnancy — pseudocholinesterase levels may be reduced

• Organophosphate or carbamate pesticide exposure — inhibited pseudocholinesterase prolongs block

• Phase II block risk — avoid repeated dosing or prolonged infusion

• Masseter muscle rigidity after administration — may herald malignant hyperthermia; discontinue volatile anaesthetics

Parameter Details

Safety Category Generally considered safe for short-term use; extensive obstetric experience

Pharmacokinetics Pseudocholinesterase levels reduced by ~25% in pregnancy; slightly prolonged duration possible

Preferred alternatives Rocuronium is alternative non-depolarising agent; succinylcholine remains standard for obstetric RSI (failed intubation/aspiration risk)

When to use Routinely used for RSI during caesarean section under general anaesthesia (AIIMS, ICMR protocols)

Monitoring Maternal ECG; fetal heart rate monitoring (fetal bradycardia rare due to minimal placental transfer)

Parameter Details

Compatibility Compatible with breastfeeding

Drug levels in milk Negligible — extremely short plasma half-life (<1 minute); highly ionised compound with poor lipid solubility

Preferred alternatives Not applicable — succinylcholine is appropriate for indicated use

Infant monitoring No specific monitoring required; breastfeeding may resume immediately after maternal recovery from anaesthesia

Parameter Recommendation

Starting dose Standard adult dose (1–1.5 mg/kg IV) unless significant frailty or low body mass

Titration Not applicable — single-dose use

Special considerations Reduced pseudocholinesterase activity may prolong duration of action; ensure extended ventilatory support capability

Additional risks Increased sensitivity to cardiac effects (bradycardia, arrhythmias); pre-existing hyperkalaemia more common; cardiovascular monitoring essential

Drug Mechanism Clinical Effect Recommendation

Volatile anaesthetics (halothane, sevoflurane, isoflurane, desflurane) Trigger agents for malignant hyperthermia Concurrent use with succinylcholine significantly increases MH risk Have dantrolene immediately available; avoid volatile anaesthetics if MH risk

Organophosphate/Carbamate pesticides Irreversible pseudocholinesterase inhibition Markedly prolonged neuromuscular block (hours to days) Avoid succinylcholine in pesticide poisoning; prolonged ventilation required if used

Echothiophate eye drops (anticholinesterase) Pseudocholinesterase inhibition Prolonged paralysis Discontinue echothiophate 4–6 weeks before elective surgery if possible

Neostigmine, Pyridostigmine (cholinesterase inhibitors) Inhibit pseudocholinesterase Prolonged succinylcholine effect Use with caution in myasthenia gravis patients on anticholinesterases

Lithium Unknown mechanism Prolonged neuromuscular blockade Monitor closely; be prepared for extended ventilation

Aminoglycosides (gentamicin, amikacin) Additive neuromuscular blockade Enhanced and prolonged paralysis Monitor neuromuscular function; ensure adequate ventilation

Drug Interaction Recommendation

Magnesium sulfate Potentiates neuromuscular blockade Common in obstetric practice (pre-eclampsia); anticipate prolonged paralysis; reduce succinylcholine dose if possible

Beta-blockers May unmask bradycardia; reduced heart rate response Atropine pretreatment advisable; continuous ECG monitoring

Calcium channel blockers May potentiate neuromuscular blockade Monitor for prolonged paralysis

Quinidine, Procainamide Potentiate depolarising block Monitor neuromuscular function

Phenytoin, Carbamazepine Chronic use may reduce succinylcholine effect (enzyme induction affecting pseudocholinesterase) May require slightly higher doses

Metoclopramide Inhibits pseudocholinesterase May prolong succinylcholine effect

Oxytocin (high doses) Weak anticholinesterase effect Slightly prolonged block possible in obstetric setting

• Muscle fasciculations (visible twitching) — almost universal

• Postoperative myalgia (muscle pain) — common, especially in young ambulatory patients and females; may persist 2–3 days

• Transient hyperkalaemia (0.5–1 mEq/L rise) — usually clinically insignificant in normal patients

• Transient bradycardia — especially with repeat dosing or in children

• Increased intraocular pressure (transient)

• Increased intragastric pressure (transient)

• Increased intracranial pressure (transient)

• Jaw rigidity (transient masseter spasm)

• Malignant hyperthermia — life-threatening emergency characterised by hyperthermia, muscle rigidity, tachycardia, hypercarbia, acidosis, rhabdomyolysis; requires immediate discontinuation of triggering agents, dantrolene sodium (2.5 mg/kg IV initial dose), aggressive cooling, and ICU admission

• Hyperkalaemic cardiac arrest — sudden asystole or ventricular fibrillation; particularly in patients with undiagnosed myopathies, burns, denervation injuries; may be refractory to standard resuscitation

• Prolonged apnoea — in pseudocholinesterase deficiency (genetic or acquired); may last hours; requires prolonged mechanical ventilation until spontaneous recovery

• Phase II (Desensitisation) block — with repeated or continuous dosing; resembles non-depolarising block; may require prolonged ventilation

• Rhabdomyolysis — particularly in children with undiagnosed muscular dystrophy; presents with myoglobinuria, hyperkalaemia, renal failure

• Anaphylaxis — rare; cross-reactivity with other neuromuscular blockers possible

• Cardiac arrhythmias — bradyarrhythmias, junctional rhythms, ventricular arrhythmias

⚠️ Dantrolene sodium and full resuscitation equipment must be immediately available wherever succinylcholine is used.

Phase Parameters

Baseline Serum potassium (especially in renal impairment, burns, trauma); ECG; personal/family history of malignant hyperthermia and neuromuscular disease; history of prolonged response to succinylcholine

During administration Continuous ECG; SpO₂; end-tidal CO₂; blood pressure; observation for fasciculations followed by flaccidity

Post-administration Return of spontaneous respiration; neuromuscular recovery (twitch response if available); airway patency and protective reflexes

If repeated dosing Peripheral nerve stimulator monitoring for Phase II block; monitor for fade pattern

Long-term Not applicable — short-acting agent for acute use only

• Scoline® (GSK/Samarth)

• Myorelax® (Neon)

• Suxacholinerase® (various)

• Quelicin® (limited availability)

• Anectine® (limited availability)

• Generic succinylcholine chloride injection (multiple manufacturers)

Note: Included in NLEM 2022; NPPA price-controlled; available in government supply.

• Airway first: Never administer succinylcholine without confirmed ability to provide positive pressure ventilation and secure the airway — paralysis without oxygenation is fatal

• Atropine in children: Pretreatment with atropine (0.01–0.02 mg/kg IV; minimum 0.1 mg) is mandatory in children <5 years and advisable before repeat dosing in any age group to prevent severe bradycardia

• Hyperkalaemia timing: Risk of life-threatening hyperkalaemia begins 24–48 hours after burns, trauma, or denervation and persists for months to years — succinylcholine is safe only in the immediate acute phase

• Undiagnosed myopathy risk: Avoid routine use in male children for elective procedures due to risk of hyperkalaemic cardiac arrest from undiagnosed Duchenne muscular dystrophy — rocuronium is safer alternative

• Malignant hyperthermia preparedness: Always have dantrolene sodium immediately available (2.5 mg/kg initial dose, up to 10 mg/kg total); masseter muscle rigidity after succinylcholine is an early warning sign

• Phase II block prevention: Avoid repeated boluses or continuous infusion — transition to non-depolarising agent (rocuronium, vecuronium, atracurium) for procedures requiring prolonged paralysis

succinylcholine; suxamethonium; neuromuscular blocker; depolarising; RSI; rapid sequence intubation; anaesthesia; malignant hyperthermia; hyperkalaemia; NLEM India; paediatric caution; emergency airway; Schedule H

RxIndia v1.0 — 10 Apr 2025

• CDSCO approved product information

• Indian Pharmacopoeia/NFI

• NLEM 2022

• AIIMS Anaesthesia Protocol Manual

• Indian Society of Anaesthesiologists Guidelines

• API Textbook of Medicine

• Harrison's Principles of Internal Medicine

• Goodman & Gilman's The Pharmacological Basis of Therapeutics

• IAP Guidelines (paediatric dosing)