Ethanol

alcohol

What it isAlcohol; a GABA-A positive modulator and NMDA antagonist.

Why this oneIt is the reference intoxicant, and its dual mechanism explains both the sedation and the withdrawal excitability.

What limits itWithdrawal is dangerous where opioid withdrawal is not, because unopposed glutamatergic rebound causes seizures and delirium.

FDA label

FDA dosing	Population	Start	Target	Max
Percutaneous transluminal septal myocardial ablation (PTSMA) in hypertrophic obstructive cardiomyopathy — reduce LV outflow tract gradient	adult	1–2 mL injected over 1–2 min into septal arterial branch (usually sufficient)	Minimum dose achieving desired gradient reduction	5 mL per procedure

Renal Undefined

Hepatic Undefined

Intra-arterial use during PTSMA only; dose guided by LVOT pressure-gradient assessment.

Administer only under supervision of a qualified interventional cardiologist experienced in PTSMA
Inspect visually — should be clear and colorless; discard unused portion
Temporary pacing wire routinely inserted before injection (transient heart block common); remove if no high-degree AV block
Continuous ECG monitoring for 48 h after the procedure; monitor for heart failure, chest pain, arrhythmias for several days

Transient heart block common at injection; ~10% of complete heart block becomes permanent, requiring pacemaker (34% pacemaker dependency in patients >60 y)
Creates a controlled myocardial infarction — excessive necrosis and heart failure reported (risk rises with alcohol volume and number of septal branches injected)
Ventricular tachycardia/fibrillation requiring cardioversion (~1%)

Pregnancy Not recommended during pregnancy; postpone PTSMA until postpartum when possible (fetal exposure not expected from septal injection).

Lactation Breastfeeding not expected to expose the child; systemic alcohol concentrations not significantly increased.

NO BOXED WARNINGS

Principal riskWithdrawal causes seizures and delirium, unlike opioid withdrawal

Direct muscarinic antagonism0 / 4