Toxicology Flashcards
Which drug is one of the more common causes of intentional oversdose because of accessibility?
Tylenol
Which drug can lead to acute hepatic failure that needs immediate intervention in an overdose?
Tylenol
What is the lethal dose of Tylenol?
10 g when acutely ingested
How long does it take for acute hepatic failure to take place in a Tylenol OD?
A day or 2
What is the maximum daily recommended dose of Tylenol?
3000mg
Tylenol metabolism (OD) in the body and how is this dangerous?
90% of the drug gets inactivated and a small percentage gets converted into NAPQI, which is a toxic metabolite that affects the liver.
When you take large amounts of it, your body can’t break it down anymore and you start to accumulate it, which leads to liver failure
What is responsible for APAP (Tylenol) metabolism that prevents toxic acuumulation of NAPQI?
Glutathione, this is hepatoprotective
Reasons you can get hepatic depletion of glutathione?
Chronic ETOH, APAP use or cirrhosis
How might a chronic APAP use present vs actue?
Chronic is more often asymptomatic and may present as a “viral syndrome”
Acute usually starts with emesis with possibly RUQ pain within 48-96 hrs, and can present as hypotensive, encephalopathy, elevations of AST/ALT and coagulopathies
How might labs present in chronic APAP use?
could be high-normal, but are mostly normal
What are good liver markers to check for in the lab?
AST/ALT, INR, Alkaline phosphatase
What do salicylate levels indicate?
ASA use
With acute APAP toxicity, what is a good lab work up?
CMP, Acetaminophen level, salicylate level, ETOH level, INR/PT
The Rumack-Matthew Nomogram is used for what?
Acute ingestion of alcohol
When can you get a Acetaminophen level?
Starting 4 hrs post ingestion
What’s makes diagnoses difficult with overdoses?
Many drugs or drug combos are often used
What is the treatment for APAP OD?
NAC (N-Acetylcysteine, Acetadote)
What does NAC do?
Replenishes glutathiones stores, which helps metabolize NAPQI
Which administration method is prefered for NAC? Why?
IV, because PO smells like rotten eggs
What can we give for massive APAP ODs?
Hemodialysis
And if it’s within an hour since ingestion, activated charcoal (but it’s not often well tolerated)
APAP OD can also cause what?
Cerebral edema, seizures
ASA toxicity can caue you to what?
Bleed
Early S/S for ASA OD? (like 1-2 hrs) Which is often the biggest clue for dx?
Tinnitus, vertigo, N/V/D, tachypnea
**Tachypnea
What happens, pathophysiologically, in an ASA OD?
You ingest a lot of acid, your body compensates via becomine tachypneic to raise CO2 levels. The patient first undergoes respiratory alkalosis. Then, the pH starts to rise and bicarb drops, becoming metabolic acidosis
Fever can occur in which kind of OD?
ASA
What ultimately causes the metabolic acidosis disturbance in ASA OD?
Anion-gap