Lecture 15: Toxicology, Drugs of Abuse, Therapeutic Drugs, etc. Flashcards
APAP
Tylenol/ acetaminophen
hydrocodone with APAP
Vicodin
oxycodone with APAP
Percocet
tramadol with APAP
Ultracet
What is the minimum single adult dose for acetaminophen?
greater than or equal to 7.5 -10 grams is usually toxic
What is the most common cause of acute liver failure in the U.S.?
Tylenol toxicity (50% of cases)
What is Phase 1 of acetaminophen toxicity?
30 minutes- 24 hours after use; anorexia, fatigue, nausea vomiting, diarrhea, diaphoresis
What is Phase 2 of acetaminophen toxicity?
18-72 hours after; RUQ abdominal pain, nausea, vomiting, tachycardia, hypotension, oliguria
what is the toxic level of serum acetaminophen?
> 250 mcg/mL
When can Reye Syndrome occur?
when a patient with a viral illness ingest or uses aspirin as a fever reducer of anti-inflammatory
What are the manifestations of Reye Syndrome?
vomiting, lethargy, neurologic symptoms- irritability, restlessness, delirium, seizures, coma
What are salicylates?
class of medication known as NSAIDs
What is Serum alcohol level/ BAC (Blood Alcohol Content)?
percentage of alcohol or mass units of alcohol in the blood
What is the rate that the body typically clears alcohol?
0.015 of BAC per hour
What is methanol and ethylene glycol typically found in?
antifreeze, windshield wiper solution, solvents, cleaners, fuels, industrial products
What are some of the symptoms of methanol intoxication?
vision blurring, central scotomata (darkening of a visual field), blindness
What are some of the symptoms of ethylene glycol intoxication?
flank plain, hematuria, oliguria
What is the estimated lethal dose of isopropyl alcohol (rubbing alcohol)?
250 mL in humans
What are the critical values for lead toxicity?
under age 16= >20 mcg/dL
over age 16= >70 mcg/dL
What is the most common cause of acute liver failure in the U.S.?
acetaminophen; symptoms don’t usually appear until 24-48 hours after ingestion
What can cause Reye Syndrome?
Aspirin –> NSAIDs
When can Reye Syndrome occur?
when a patient with a viral illness ingests or uses aspirin as a fever reducer of anti-inflammatory
What are the manifestations of Reye syndrome?
vomiting, lethargy, neurologic symptoms
What is the rate at which the body clears alcohol?
.015 BAC per hour
Where is methanol and ethylene glycol typically found?
antifreeze, windshield wiper solutions, cleaners, fuels, and industrial products
What are the symptoms of methanol intoxication?
vision blurring, central scotomata, blindness
What are the symptoms of ethylene glycol intoxication?
flank pain, hematuria, oliguria
Were is isopropyl alcohol found?
disinfectants, antifreeze, solvents, and most commonly rubbing alcohol
What will patients with lead poisoning present with?
decline in mental status, muscle weakness, headaches, memory loss, mood disorder, premature birth, multiple renal, gastrointestinal, neurologic and hematologic manifestations , and hearing loss
Where is mercury found?
thermometers, mining, contaminated fish, Chinese medicine
What can severe exposure of mercury lead to?
fatal pneumonitis, intention tremor, gum inflammation, excessive salivation, psychiatric symptoms
children can develop pink disease
excessive can cause renal toxicity
Where can arsenic be found?
volcanic eruptions, contaminated water, pesticides, mining, Asian herbal remedies, some apple or grape juices
What are the presentations of arsenic poisoning?
nausea, EKG abnormalities, hypotension, arrhythmias, seizures, hepatices, skin lesion(hyperpigmentation is common as an early sign), cancer
What does the basic urine drug screen test for?
amphetamines, cocaine, marijuana, opioids, phencyclidines (PCP)
What can be used for a drug of abuse screening?
urine- most common, blood/serum- 2nd most common, hair, feces, sweat, saliva
Addition of what substance alters DOA screening result?
Zinc sulfate
What all can be measured to avoid subversion tactics in DOA screenings?
urine specific gravity, temperature, pH, creatinine
What things can produce false positive amphetamine results?
OTC products, nasal decongestants, ephedrine, bupropion, and selegiline
What does a cocaine drug screen detect?
benzoyleconine (a cocaine metabolite)
Are false positives common in DOA screenings for cocaine?
no extremely uncommon
What doe THC drug screen detect?
metabolite Delta-9-THC
What are some benzodiazepines?
alprazolam, diazepam, Lorazepam, clonazepam, midazolam, triazolam… does not detect sleep medications such as Zolpidem etc.
What is digoxin?
antiarrhythmic agent used in atrial fibrillation, congestive heart failure… has a narrow therapeutic index
What are the causes of digoxin poisoning?
arrhythmias, nausea, vomiting, confusion, weakness, visual changes
What patients should digoxin be monitored in?
elderly, renal impairment, low potassium or magnesium
When does the baseline level for digoxin occur?
7 days after initiating digoxin
What are the anticonvulsants that require monitoring?
carbamazepine, divalproex sodium, valproate sodium, phenobarbital, phenytoin, primidone
What is the indication of lithium?
used in the treatment of bipolar disorder as an anti-manic agent and to reduce risk of suicide
What are the signs of lithium toxicity?
nausea, vomiting, dehydration, ECG changes, bradycardia, ataxia, confusion, agitation, tremors, jerks
What can occur because of vancomycin?
nephrotoxicity and renal failure
What is vancomycin used for?
gram positive infections, C, diff, MRSA, meningitis, community/hospital acquired pneumonia
How can you avoid toxicity from vancomycin?
draw trough levels
When are trough levels checked in vancomycin?
just before the 4th dose- steady state
What is theophylline?
medication used to treat reactive airway disease and works as a bronchodilator
When should you check theophylline levels?
when increasing the dosage, symptoms of toxicity are present, symptoms are worsening, when treatment or medication changes are made that affect theophylline
What is methotrexate used to treat?
severs psoriasis, rheumatoid arthritis, acute lymphoblastic lymphoma, breast cancer, non Hodgkin’s lymphoma, other cancer therapy
Low dose methotrexate therapy
Pulmonary toxicity, hepatotoxicity, myelosuppression and GI distress
high dose methotrexate therapy
Above + Stomatitis, nephrotoxicity, neurologic toxicity, severe rash than can lead to desquamation
What should you administer if a person has toxic levels of methotrexate?
leucovorin
carbon monoxide binding affinity
Carbon monoxide demonstrates a higher binding affinity for the heme portion of hemoglobin than oxygen by a factor of 240!
How can one screen for carboxyhemoglobin?
patient history plus carboxyhemoglobin level done on arterial blood gas
What are some causes of increase methemoglobin?
congenital Methemoglobinemia ; most cases autosomal recessive
What is methemoglobin?
Normally, the iron moiety in hemoglobin is found in the ferrous Fe2+ state but a small percentage (~1%) exists in the oxidized ferric state Fe3+
acquired Methemoglobinemia
TOXINS
nitrites, medications such as dapsone and topical anesthetics, well water, chlorates
What is the clinical presentation of methemoglobin?
blue color skin, cyanosis, headache, dyspnea, lightheadedness (even syncope), weakness, confusion, palpitations, chest pain, altered mental status, delirium, some death
