Page 1740 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 124: Toxicology in Adults 1209

TABLE 124-22 Toxic Alcohols: Clinical Features and Management
Sources Distinguishing Features Pharmacokinetic/Pharmacodynamic Parameters Specific Treatment
Methanol (Metabolites: Formaldehyde, Formic Acid, Lactic Acid)
Antifreeze Optic papillitis Lethal serum level: 80-100 mg/dL Charcoal (<1-2 h after ingestion)
Lethal dose: 150-240 mL of a 40% solution Ethanol, 4-methylpyrazole
Solvent Pancreatitis Peak conc.: 30-90 min Consider bicarbonate infusion
Vd: 0.6 L/kg Folate 50-70 mg IV q4h × 24 h
Fuel Excretion: 90%-95% saturable hepatic metabolism; 5%-10% unchanged renal HD until serum level <20 mg/dL for:
1. Serum level >50 mg/dL
Half-life is dose dependent: Mild intoxication: 14-20 h Severe intoxication: 24-30 h 2. Eye involvement
With ethanol: 30-35 h Ethanol + HD: 2.5 h 3. Altered mental status
4. Ingestion of >30 mL
5. Elevated formic acid level
6. Refractory metabolic acidosis
Ethylene Glycol (Metabolites: Glycoaldehyde, Glycolic Acid, Oxalic Acid)
Antifreeze Acute renal failure Lethal serum level: 19.2 mg/dL GL (<1-2 h after ingestion)
Lethal dose: 100 mL Ethanol, 4-methylpyrazole
Solvent Crystalluria Peak conc.: 1-4 h Thiamine 100 mg IM qid
Vd: 0.6 L/kg Pyridoxine 500 mg IM qid
Wood light: urinary fluorescence Excretion: hepatic metabolism Consider bicarbonate infusion
Half-life: Consider calcium administration
Myocardial dysfunction Untreated: 3-8.5 h Consider forced diuresis
With ethanol: 10-102 h HD until serum level 20 mg/dL for:
Ethanol + HD: 2.5-3 h 1. Serum level >50 mg/dL
2. End-organ damage
3. Refractory metabolic acidosis
Isopropanol (Metabolite: Acetone)
Rubbing alcohol Hemorrhagic Lethal serum level: 400 mg/dL Supportive care
gastritis Lethal dose: 150-240 mL of 40% solution (highly variable) GL (<1-2 h after ingestion)
Solvents Ethanol not indicated (nontoxic metabolites)
Ketonemia Peak conc.: <2 h
Deicers Vd: 0.6 L/kg HD for:
Ketonuria Excretion: 50%-80% hepatic metabolism; 20%-50% unchanged renal 1. Serum level >400 mg/dL
2. Shock
No acidosis or hyperglycemia Half-life: Untreated: 2.5-3 h 3. Prolonged coma
4. Hepatic or renal insufficiency
GL, gastric lavage; HD, hemodialysis; Vd, volume of distribution.

Hemodialysis can be performed concurrently with fomepizole if clini- Loading dose: 600 mg/kg ethanol IV
cally indicated. Hemodialysis is indicated for serum levels above 50 mg/dL Maintenance dose:
(for both ethylene glycol and methanol), significant acidosis (pH
<7.25), renal failure, or deteriorating vital signs. Specifically in the case Nonalcoholic patient: 66 mg/kg per hour ethanol by continuous IV
of methanol, hemodialysis is indicated if there are vision abnormalities infusion
at time of diagnosis. The dose of fomepizole needs to be adjusted Alcoholic patient: 154 mg/kg per hour ethanol by continuous IV infusion
132
during hemodialysis: by either decreasing the dosing interval to every Patients receiving HD: double continuous infusion rate
4 hours or giving the patient an infusion of fomepizole 1 to 1.5 mg/kg/h
133
during dialysis sessions. In the absence of other indications for Intravenous ethanol is supplied as a 10% solution in 5% dextrose,
hemodialysis, a methanol or ethylene glycol level greater than 50 mg/dL containing 10 g of ethanol per 100 mL of solution. Blood ethanol levels
may be treated with fomepizole alone (and no hemodialysis) with close should be maintained in the target range during hemodialysis by either
monitoring of pH and renal function. 134,135 dialysis bath supplementation with 200 mg/dL ethanol or doubling the
Ethanol is used when fomepizole is unavailable or the patient has an dose of intravenous ethanol infusion. 137,138
allergy to fomepizole. Ethanol can be administered orally or intrave- A high index of clinical suspicion is necessary to identify methanol-
nously aiming for a level of 100 to 200 mg/dL. One protocol for thera- or ethylene glycol–intoxicated patients to allow for appropriate inhi-
peutic ethanol administration is as follows : bition of metabolism and urgent dialysis. We also recommend ADH
136

section11.indd 1209 1/19/2015 10:51:59 AM