Overdose Emergencies

Drug overdose has been a huge topic in Canada recently. Opioid painkiller addiction and fentanyl use have constantly been on TV, either as incidents leading to news reports or documentary/journalism pieces bringing about awareness. Not to mention tabloids blasting the alleged details of various actors’ drug rehab fails. So the issue of drug overdose is really not a new one. Below are some general guidelines to follow.

If the patient is alert enough, try to take as much history as possible: which substance did they use? How much did they use? Via what route? How much time has passed since usage? It’s also important to document the factors that can determine outcome, such as age, weight, underlying medical problems, and other medications. Remember to ask about suicide ideation and intention.

Always suspect overdose when:

·      Altered level of consciousness/coma

·      Young patient with life-threatening dysrhythmia

·      Trauma patient

·      Bizarre or puzzling clinical presentation

Manage DRABC first. DRAB is the same as conventional protocol, but D can be split into three different meanings: drugs, draw bloods, and decontamination (decrease absorption or increase elimination). E stands for examine the patient and exposure to specific toxidromes. F stands for full vitals monitoring (e.g. ECG, urinary catheter, X-rays); conduct physical examination with emphasis on vital signs, GCS, and pupils. The definitive treatment depends on what the patient has overdosed on.

Universal antidotes (remember DON’T):

D—dextrose

O—oxygen

N—naloxone

T—Thiamine (must give this BEFORE dextrose)

Naloxone administration may cause opioid withdraw in chronic users. Mild symptoms of opioid withdraw may include lacrimation, rhinorrhea, diaphoresis,

yawning, piloerection, hypertension, and tachycardia. Severe withdraw symptoms include hot and cold flushes, arthralgia, myalgia, abdominal cramping, and nausea and vomiting.

Blood work should include:

·      General: CBC, BUN/creatinine, glucose, INR/PTT, osmolality

·      ABG and oxygen saturation

·      Protein and albumin

·      Lactate

·      Ketones

·      Liver enzymes

·      Creatine kinase

·      Electrolytes and especially the following

o   Calcium

o   Magnesium

o   Phosphophate

·      Drug levels (can guess based on history and clinical findings)

o   Acetylsalicylic acid (ASA)

o   Acetaminophen

o   Ethanol

o   Urine screens also available

o   Remember negative toxicology screen does not rule out a toxic ingestion

Decontamination and enhanced elimination really depends on the area affected. For ocular, use saline irrigation to neutralize pH; alkali exposure requires ophthalmology consult. Dermal decontamination requires the removal of patient’s clothing (wear protective gear!), brush off toxic agents, and irrigate all external surfaces. For gastrointestinal decontamination, a single dose of activated charcoal can be given; beware that lithium, iron, alcohols, lead, and caustics are NOT absorbed by activated charcoal. Slow whole bowel irrigation (500ml in adults and slowly increase rate hourly) can be carried out.

Hemodialysis is use for the ingestion of methanol, ethylene glycol, salicylates, lithium, phenobarbital, chloral hydrate, theophylline, carbamazepine, valproate, and methotrexate. It can also be used in those who have impairment in normal mode of elimination.

Physical examination:

·      Vital signs (including temperature)

·      Skin (needle tracks, color) and mucous membranes

·      CNS, pupils

·      Odor

·      Head-to-toe survey

o   C spine

o   Signs of trauma, seizures (incontinence, tongue-biting), infection (meningismus), chronic alcohol/drug abuse (track marks, nasal septum erosion)

·      Mental status

Below is a guide to differential diagnosis based on clinical laboratory findings. It’s good to know, but I don’t think it’s absolutely necessary to commit to memory.

Below are two tables showing some toxidromes. I think it’s useful as a reference, but once again I don’t think it’s necessary to commit to memory because it’s just far too much and too complex.

Definitive treatment involves giving specific antidotes and treatments.

Substance	Antidote
Acetaminophen	N-acetylcysteine
Anticholinergics	Physostigmine
Benzodiazepines	Flumazenil
Calcium channel blockers	Calcium chloride, calcium gluconate
Cyanide or nitrate	Methylene blue
Digoxin	Digoxin immune fab
Heparin	Protamine sulfate
Iron	Deferoxamine
Insulin	Glucagon
Lead	Succimer
Opioids	Naloxone or nalmefene
Warfarin	Vitamin K

Warfarin overdose treatment is dependent on the INR of the patient.

<5.0                Hold warfarin, observation, and serial INR/PT

5.1~9.0          If no risk of bleeding, hold warfarin for 1~2 days and reduce maintenance dose. If risk of bleeding, vitamin K 1~2mg PO.

9.1~20.0        Hold warfarin, vitamin K 2~4mg PO, serial INR/PT, additional vitamin K if necessary

>20.0              Hold warfarin, vitamin K 10mg IV over 10min, increase dosing every 4 hours if needed

Lastly, here are some extra random bits of information that may prove to be useful—but I don’t think it’s necessary to commit this to memory.

As usual, you are most welcome to contribute further by posting on comment section below. Any suggestions for future episodes are also welcome. 

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