Toxicology

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Poisoning and Drug Overdose
Decontamination:
-Gastric Lavage: Place patient left side down, place
nasogastric tube, and check position by injecting air
and auscultating. Lavage with normal saline until
clear fluid, then leave activated charcoal or other
antidote. Gastric lavage is contraindicated for
corrosives.
-Cathartics:
-Magnesium citrate 6% solution 150-300 mL PO
-Magnesium sulfate 10% solution 150-300 mL PO.
-Activated Charcoal: 50 gm PO (first dose should be
given using product containing sorbitol). Repeat
q2-6h for large ingestions.
-Hemodialysis should be for isopropanol, methanol,
ethylene glycol, severe salicylate intoxication (>100
mg/dL), lithium, or theophylline (if neurotoxicity,
seizures, or coma).
Antidotes:
Narcotic Overdose:
-Naloxone (Narcan) 0.4 mg IV/ET/IM/SC, may
repeat q2min.
Methanol Ingestion:
-Ethanol (10% in D5W) 7.5 mL/kg load, then 1.4
mL/kg/hr IV infusion until methanol level <20
mg/dL. Maintain ethanol level of 100-150 mg/100
mL.
Ethylene Glycol Ingestion:
-Fomepizole (Antizol) 15 mg/kg IV over 30 min,
then 10 mg/kg IV q12h x 4 doses, then 15 mg/kg
IV q12h until ethylene glycol level is less than 20
mg/dL AND
-Pyridoxine 100 mg IV q6h for 2 days and thiamine
100 mg IV q6h for 2 days.
Carbon Monoxide Intoxication:
-Hyperbaric oxygen therapy or 100% oxygen by
mask if hyperbaric oxygen is not available.
Tricyclic Antidepressants Overdose:
-Gastric lavage
-Magnesium citrate 300 mg PO/NG x1.
-Activated charcoal premixed with sorbitol 50 gm
NG round-the-clock until level is less than the
toxic range.
Benzodiazepine Overdose:
-Flumazenil (Romazicon) 0.2 mg (2 mL) IV over 30
seconds q1min until a total dose of 3 mg; if a
partial response occurs, repeat 0.5 mg doses
until a total of 5 mg. If sedation persists, repeat
the above regimen or start a continuous IV
infusion of 0.1-0.5 mg/h.
Labs: Drug screen (serum, gastric, urine); blood levels,
SMA 7, fingerstick glucose, CBC, LFTs, ECG.
Acetaminophen Overdose
1.Admit to: Medical intensive care unit.
2.Diagnosis: Acetaminophen overdose
3.Condition:
4.Vital Signs: q1h with neurochecks. Call physician if
BP >160/90, <90/60; P >130, <50 <50; R>25, <10;
urine output <20 cc/h for 3 hours.
5.Activity: Bed rest with bedside commode.
6.Nursing: Inputs and outputs, aspiration and seizure
precautions. Place large bore (Ewald) NG tube, then
lavage with 2 L of NS.
7.Diet: NPO
8.IV Fluids:
9.Special Medications:
-Activated charcoal 30-100 gm doses, remove via
nasogastric suction prior to acetylcysteine.
-Acetylcysteine (Mucomyst, NAC) 5% solution loading
dose 140 mg/kg via nasogastric tube, then 70
mg/kg via NG tube q4h x 17 doses OR acetylcyst-
eine 150 mg/kg IV in 200 mL D5W over 15 min,
followed by 50 mg/kg in 500 mL D5W, infused over
4h, followed by 100 mg/kg in 1000 mL of D5W over
next 16h. Complete all NAC doses even if
acetaminophen levels fall below toxic range.
-Phytonadione (Aquamephyton) 5 mg IV/IM/SQ (if INR
increased).
-Fresh frozen plasma 2-4 U (if INR is unresponsive to
Aquamephyton).
-Trimethobenzamide (Tigan) 100-200 mg IM/PR q6h
prn nausea.
10. Extras: ECG.
11. Labs: CBC, SMA 7&12, LFTs, INR/PTT, acet-
aminophen level now and in 4h. UA.
Theophylline Overdose
1.Admit to: Medical intensive care unit.
2.Diagnosis: Theophylline overdose
3.Condition:
4.Vital Signs: Neurochecks q2h. Call physician if BP
>160/90, <90/60; P >130; <50; R >25, <10.
5.Activity: Bed rest
6.Nursing: ECG monitoring until level <20 mcg/mL,
aspiration and seizure precautions. Insert single
lumen NG tube and lavage with normal saline if recen
ingestion.
7.Diet: NPO
8.IV Fluids: D5 ½ NS at 125 cc/h
9.Special Medications:
-Activated charcoal 50 gm PO round-the-clock, with
sorbitol cathartic, until theophylline level <20 m-
cg/mL. Maintain head-of-bed at 30-45 degrees to
prevent aspiration of charcoal.
-Charcoal hemoperfusion should be considered if the
serum level is >60 mcg/mL or if signs of neurotox-
icity, seizure, coma are present.
-Seizure: Lorazepam (Ativan) 0.1 mg/kg IV at 2
mg/min; may repeat x 1 if seizures continue.
10. Extras: ECG.
11. Labs: CBC, SMA 7&12, theophylline level now and
in q6-8h; INR/PTT, liver panel. UA.
Tricyclic Antidepressant Overdose
1.Admit to: Medical intensive care unit.
2.Diagnosis: TCA Overdose
3.Condition:
4.Vital Signs: Neurochecks q1h.
5.Activity: Bedrest.
6.Nursing: Continuous suicide observation. ECG
monitoring, measure QRS width hourly, inputs and
outputs, aspiration and seizure precautions. Place
single-lumen nasogastric tube and lavage with 2 liter
of normal saline if recent ingestion.
7.Diet: NPO
8.IV Fluids: NS at 100-150 cc/hr.
9.Special Medications:
-Activated charcoal premixed with sorbitol, 50 gm via
NG tube q4-6h round-the-clock until the TCA level
decreases to therapeutic range. Maintain head-of-
bed at 30-45 degree angle to prevent charcoal
aspiration.
-Magnesium citrate 300 mL via nasogastric tube x 1
dose.
10.Protection Against Cardiac Toxicity:
-If mechanical ventilation is necessary, hyperventilate
to maintain pH 7.50-7.55.
-Administer sodium bicarbonate 50-100 mEq (1-2
amps or 1-2 mEq/kg) IV over 5-10 min, followed by
infusion of sodium bicarbonate (2 amps in D5W 1 L
at 100-150 cc/h. Adjust rate to maintain pH 7.50-
7.55.
11.Extras: ECG.
12.Labs: Urine toxicology screen, serum TCA levels,
liver panel, CBC, SMA-7 and 12, UA.