Medications Used in General Anesthesia for ECT Sessions
The standard anesthetic regimen for ECT consists of methohexital (1.0 mg/kg IV) for induction, succinylcholine (0.9 mg/kg IV) for muscle relaxation, and atropine or glycopyrrolate for anticholinergic protection, with 100% oxygen ventilation before electrical stimulus. 1
Primary Anesthetic Agents
Induction Agents
Methohexital is the preferred anesthetic agent for ECT and should be used as first-line unless specific contraindications exist 1. The optimal induction dose is 1.0 mg/kg IV for most patients 2.
Acceptable alternatives to methohexital include:
- Etomidate - produces longer seizure durations than methohexital and should be considered first-line when patients have inadequate seizure duration despite high electrical stimulation 1, 3
- Thiopental sodium - acceptable alternative but may increase seizure threshold more than methohexital 1
- Ketamine - listed as acceptable alternative 1
- Propofol - has specific limited indications only: patients with preexisting cardiac conditions requiring attenuated hemodynamic response, patients with excessively prolonged seizures (>180 seconds), or severe post-ictal nausea and vomiting 4
Muscle Relaxants
Succinylcholine is the standard muscle relaxant at a dose of 0.9 mg/kg IV, though considerable individual variability exists in patient response 1, 2.
Acceptable alternatives to succinylcholine:
Anticholinergic Medications
Atropine or glycopyrrolate must be administered immediately before ECT to prevent bradycardia, arrhythmia, or occasional ECT-induced cardiac asystole 1.
Premedication with anticholinergics is required:
- Before seizure threshold determination by dose titration method 1
- Before the first treatment with right unilateral electrode placement 1
- To protect the cardiovascular system from vagal discharge in instances of incomplete or missed seizures 1
Ventilation Protocol
Patients must be ventilated with 100% oxygen before administration of the electrical stimulus 1.
Critical Comparative Considerations
Seizure Duration Effects
Etomidate produces the longest seizure durations (EEG: 76-78 seconds; motor: 42-44 seconds) without dose-dependent variation across the range of 0.15-0.3 mg/kg 5. In seizure-resistant patients, etomidate reduces the required electrical stimulation dose from 638 to 497 millicoulombs while increasing seizure duration by 65% compared to thiopental 3.
Methohexital produces intermediate seizure durations with dose-dependent decreases: at 0.75 mg/kg (EEG: 58s, motor: 37s), at 1.0 mg/kg (EEG: 62s, motor: 36s), and at 1.5 mg/kg (EEG: 48s, motor: 29s) 5.
Propofol produces the shortest seizure durations with marked dose-dependent decreases: at 0.75 mg/kg (EEG: 56s, motor: 34s), at 1.0 mg/kg (EEG: 50s, motor: 31s), and at 1.5 mg/kg (EEG: 33s, motor: 20s) 5.
Side Effect Profiles
Methohexital is associated with more side effects during and immediately after ECT compared to etomidate 6.
Propofol provides rapid recovery and minimal post-ictal nausea/vomiting, making it specifically indicated when patients experience severe nausea and vomiting after ECT with methohexital 4.
Special Population Considerations
Adolescents
Adolescents may have lower seizure thresholds and more prolonged seizures than adults during ECT 1. In one series, 53% of adolescents treated with ECT required switching from methohexital to propofol due to prolonged seizures, and 33% had seizures longer than 180 seconds requiring termination 4.
Management of Prolonged Seizures
Seizures lasting longer than 180 seconds are considered prolonged and can be effectively terminated with additional methohexital, diazepam, or lorazepam 1. Propofol should be considered as the primary anesthetic for subsequent treatments in patients who have experienced prolonged seizures 4.
Common Pitfalls to Avoid
Do not use propofol as first-line anesthetic unless specific indications exist (cardiac disease, prolonged seizures, or severe nausea/vomiting), as its anticonvulsant properties may compromise therapeutic efficacy 4.
Do not administer anticholinergics inconsistently - they are mandatory before threshold determination and first unilateral treatments to prevent potentially dangerous vagal responses 1.
Do not fail to adjust anesthetic dosing based on individual patient response during the treatment course, as the optimal dose of methohexital (1.0 mg/kg) and succinylcholine (0.9 mg/kg) represents population averages with significant individual variability 2.