Toxicology 2: Essential Antidotes Portal
Considering the number of varied exposures and potentially toxic chemicals, few antidotes are available to reverse or halt the toxic effects of the various substances. Below is a table of commonly used antidotes and administration instructions. PEDS: Note pediatric dosages. For more information, call the Poison Center at 1-800-222-1222.
| Antidote | Indications | Dose |
| Acetylcysteine (NAC) | Acetaminophen | 140 mg/kg loading dose; maintenance 70 mg/kg every 4 hours for 17 doses |
| Atropine | Cholinergic agents— organophosphate and carbamate insecticide poisoning, nerve gases |
Adults: 1 to 5 mg IV; PEDS: 0.05 mg/kg IV; repeat every 5 to 10 min until secretions are dry |
| Sodium bicarbonate | Metabolic acidosis from methanol, ethylene glycol, or salicylates | 1 to 2 mEq/kg IV bolus; repeat as needed to blood pH of at least 7.2 |
| Urinary alkalinization in salicylate or phenobarbital overdose | 0.5 to 1.0 mEq/kg IV bolus over 2 min; infusion of 100 to 150 mEq in 1 L D5W at rate of 2 to 4 mL/kg/h to maintain urine pH > 7.0 | |
| QRS widening > 100 msec secondary to a TCA or other toxin that poisons sodium channel | 1 to 2 mEq/kg IV bolus; repeat as needed and maintain blood pH at 7.45 to 7.5 | |
| Myoglobinuria in rhabdomyolysis | 1 to 1.5 mEq/kg added to each liter of D5W to maintain urine alkalinization pH > 7.0 | |
| Benztropine (Cogentin) | Acute dystonic reaction from neuroleptics or metoclopramide (Reglan) | 1 to 2 mg IV or IM (PEDS: children > 3 years: 0.02 mg/kg to 1 mg maximum) |
| Calcium |
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| Cyanide antidote kit | Strong suspicion of cyanide poisoning (depressed LOC, metabolic acidosis, elevated serum lactate) |
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| Deferoxamine (Desferal) (Iron-chelating agent) | Iron poisoning usually levels > 450 to 500 µg/dL or significant signs and symptoms (eg, shock, acidosis) | Infuse at rate of 10 to 15 mg/kg/hour (not to exceed 6 g/24 hours) |
| Digoxin-specific antibodies (Digibind, DigiFab) | Cardiac glycoside poisoning | Digoxin: number of vials=serum digoxin level (ng/mL) X weight (kg)÷100 (Vol III—CV10) |
| DMSA (succimer) | Lead and mercury intoxication | 10 mg/kg PO q 8 h for 5 d then q 12 h for 14 days |
| Dimercaprol (BAL) | Arsenic, mercury, lead poisonings with encephalopathy | 3 mg/kg deep IM q 4 to 6 h for 2 days then q 12 h for 7 to 10 days or until recovery. In severe cases, give 4 to 5 mg/kg deep IM q 4 h for 3 to 5 days. |
| EDTA, calcium Calcium Disodium Edetate (ethylenediamine tetraacetic acid, EDTA) | Lead poisoning with encephalopathy | 20 to 30 mg/kg in 2 to 3 divided doses deep IM or continuous infusion diluted to 20 to 30 mg/kg given over 8 to 12 hours for 5 days. Stop therapy for 2 to 4 days and repeat a 5-day course. |
| Ethanol | Methanol and ethylene glycol poisonings.
Ethanol competes with the toxic alcohols for alcohol dehydrogenase. PEDS: Ethanol can cause hypoglycemia in children. Fomepizole is now preferred over ethanol for treatment of toxic alcohol ingestion. |
Loading dose of 0.7 mL/kg of 10% ethanol IV in D5W over 30 to 60 min; 1 to 2 mL/kg/h to maintain blood level of 100 to 150 mg/dL. PEDS: Decrease dose for children and non-drinkers, higher for alcoholics. (Increase 2 to 3 mL/kg/hour during hemodialysis.) Orally: 40% ETOH (80 proof liquor) 2.5 mg/kg then 0.3 to 0.5 mL/kg/h. Watch for change in LOC. PEDS: Measure glucose every hour. |
| Fomepizole (Antizol, 4-MP) | Methanol and ethylene glycol (EG) poisoning. Fomepizole is now preferred over ethanol for treatment of toxic alcohol ingestion. | 15 mg/kg loading dose, then 10 mg/kg q 12 h x 4 doses, then 15 mg/kg q 12 h until EG or methanol level < 20 mg/dL. Each dose should be given over 30 min IV. |
| Flumazenil (Romazicon) | Benzodiazepine overdose | 0.2 mg IV over 30 seconds; if no response, give 0.3 mg; if no response, give 0.5 mg and repeat every 30 seconds prn to maximum 3 mg |
| Glucagon | Beta blocker overdose (Consider in CCB overdose) | 5 to 10 mg IV followed by 1 to 5 mg/h infusion |
| Glucose | Hypoglycemia and empiric therapy for patients with altered mental status and seizures | 50 to 100 mL of D50 IV PEDS: 2 to 4 mL/kg of D25, not D50; neonates: 2 to 4 mL/kg D10IV |
| Insulin with glucose | Hypotension or bradycardia from calcium channel blockers and beta blockers | Initial bolus dose: 10 U of insulin and 25 g of dextrose (50 mL of D50 IV). Maintenance dose: Insulin 0.5 to 1IU/kg/h and Dextrose 5 to 75 g/h. Begin at 7.5 to 10 g/h Use central venous catheter if infusing > 10% glucose solution. |
| Methylene blue | Methemoglobinemia (Nitrite exposure and other causes of MetHb) | 1 to 2 mg/kg of 1% solution IV over 5 min; may repeat in 30 to 60 minutes |
| Naloxone (Narcan)a | Opioid overdose and empiric therapy for patients with altered mental status | 1 to 2 mg IV; may repeat 1 mg every 2 to 3 min prn; Infusion: 2/3 initial dose needed to reverse effects per hour in D5W |
| Octreotide (Sandostatin) | Recurrent hypoglycemia from sulfonylureas | 1 μg/kg SQ every 12 hours or 15 to 30 mg/kg/min continuous IV infusion, titrate prn. PEDS: 1 to 10 μg/kg/dose given SQ or as IV infusion every 12 hours |
| Oxygen | CO (carbon monoxide) poisoning | 100% by mask or at 2 to 3 atm in hyperbaric chamber |
| Physostigmine (Antilirium) | Severe anticholinergic poisoning | 0.5 to 2 mg IV over 2-3 min; may repeat in 20 to 30 min; should not be used in TCA overdose |
| Pralisoxime (2-PAM) | Cholinergic agents—organophosphate insecticide poisoning, nerve gases | Load 1 to 2 g IV over 15 to 30 min, then 500 mg/h; PEDS: Load 20 to 40 mg/kg IV over 15 to 30 min |
| Protamine sulfate | Large heparin overdose | 1 mg for each 100 U of heparin. Give less if time since heparin overdose is longer than 30 min |
| Pyridoxine (Vitamin B6) | Isoniazid (INH) induced seizures and overdose and Gyrometra mushroom ingestion | 1 g IV for each gram of INH ingested. Dilute in 50 mL dextrose or NS and give over 5 minutes. When ingested amount is unknown, give 5 grams IV; repeat prn. |
| Vitamin K1 (Phytonadione) (Aqua Mephyton) | Warfarin (Coumadin) overdose | Adult: 5 to 10 mg SQ; repeat in 6 to 8 h. (Switch to oral ASAP, 10 to 25 mg/day.) PEDS: 1 to 5 mg SQ; repeat in 6 to 8 h. (Switch to oral ASAP, 5 to 10 mg/d.) |
Reference
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Koenig KL. Intranasal naloxone is effective for opioid overdose. Journal Watch Emergency Medicine. October 30, 2009.