toxins/pharmacology Flashcards by Sidney James

What 4 toxins are not removed with charcoal?

CALM = cyanide, alcohol, lithium and heavy metals

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A 3 y/o swallowed a battery 3 days ago. He is asymptomatic. What do you do?

Endoscopy. If in the esophagus or stomach it must be removed

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When should swallowed coins be removed?

If proximal esophagus - endoscopy ASAP!

If middle to lower esophagus, observe 24 hours if asymptomatic and if does not pass then endoscopy needed

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What are 3 initial manifestations of Tylenol toxicity?

Anorexia, nausea and vomiting

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How long is the latent phase of acetaminophen toxicity?

1-4 days with significant rise of liver enzymes

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What are the important 4hr post Tylenol ingestion levels to remember?

>150 = moderate toxicity
>300 = severe toxicity

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Female ingested Tylenol 2 days ago. Acetaminophen level 4 hr post ingestion was 250 and she was treated with N acetylcysteine. Today LFTs are normal. What is her prognosis?

LFTs can be normal until 4 days after ingestion even after severe overdose! Pt is still in danger…

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What is the initial management of acetaminophen ingestion ?

Charcoal then 4 hour post ingestion level

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If >150mg/kg has been ingested, what should you do?

Immediately give N acetylcysteine, even before obtaining post ingestion levels

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If a patient had wintergreen odor on breath, what should you be concerned about?

Aspirin ingestion

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What is the initial treatment of salicylate ingestion?

Charcoal then 3-6hr post ingestion level

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How do you manage ibuprofen ingestion ? What should you NOT do?

Do give supportive care and test for co-ingestion of aspirin or Tylenol
Do not give ipecac or gastric lavage,

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What occurs physiologically after aspirin ingestion?

Respiratory alkalosis due to increased breathing –> buildup of organic acids and anion gap metabolic acidosis

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What is the formula for anion gap?

Na - (Cl + bicarb)

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What is the treatment for anion gap metabolic acidosis secondary to aspirin ingestion and why?

Sodium bicarb to alkalinize the urine

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Which ingestion is associated with hypoglycemia ?

Ethyl alcohol

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At what blood alcohol level can coma, respiratory depression and death occur?

> 0.4

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What products contain methanol?

Rubbing alcohol, Windshield washer fluid, cooking fuel, perfumes and antifreeze

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Clinical presentation of methanol ingestion …

Acidosis, increased anion gap and CNS depression

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What is the antidote to methanol toxicity and why?

4-methypyrazole or ethanol –> alcohol dehydrogenase antagonist which slows conversion to formaldehyde

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What are the classic symptoms of opiate toxicity?

Responsive to painful stimuli
Pinpoint but reactive pupils
Respiratory depression
Bradycardia, hypotension and low temperature

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How can you differentiate opioid toxicity from dka?

Dka has rapid deep breathing with no miotic pupils

Opiates cause shallow breathing with miotic pupils

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How can you differentiate opioid toxicity from organophosphate poisoning?

Both have pinpoint pupils but only organophosphate shave sweating, tearing and wheezing

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What toxicity would be suspected in a person with dilated pupils and violent behavior?

Pcp

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What is propoxyphene and what can it cause ?

Narcotic analgesic that can cause ventricular arrhythmia, seizures and pulmonary edema

What is the mechanism of action of organophosphates?

Acetylcholinesterase inhibitor

What are the classic signs of organophosphate poisoning?

DUMBBELS = diarrhea, urination, miosis, bronchospasm, bradycardia, emesis, lacrimation, salivation

What are the muscarinic effects of cholinergics and how are they treated?

Bronchospasm and increase pulmonary secretions - give atropine

What are the nicotinic effects of cholinergics and how are they treated?

Neuromuscular effects / treat with pralidoxime

What are the life threatening signs associated with TCA ingestion and when does this occur?

Dysthymia and hypertension occurs within 24 hours

What medications classically are known to have anticholinergic side effects?

Tricyclics, pupil dilator agents and antispasmodics

What are the anticholinergic signs?

``` Blind as a bat (dilated pupils) Red as a beet Hot as a hare Dry as a bone Mad as a hatter Bowel and bladder lose their tone Heart runs alone ```

How do you manage TCA ingestion?

Charcoal alkalinization of urine EKG monitoring for wide QRS

How do you treat a widening QRS after TCA poisoning?

Sodium bicarb boluses until QRS <100 msec

What are symptoms of beta blocker ingestion?

Depressed sensorium, bradycardia, hypotension and diaphoresis

What types of testing is invalid if a patient is taking TCAs and why?

TCAs render allergy testing unreliable because they interfere with histamine response

What occurs on labs and imaging after hydrocarbon ingestion?

Hypoxemia and ARDS (diffuse bilateral infiltrates on cxr)

How do you treat an asymptomatic patient after hydrocarbon ingestion?

Observation x 6 hours with pulse oximetry.

What ingestion should you consider in a patient with confusion and weakness but no fever?

Carbon monoxide

You are presented with a patient who is lethargic, confused and in distress. Vitals are normal. What is the best treatment?

100% oxygen

If suspected carbon monoxide poisoning but no improvement of symptoms despite 100% oxygen what should you consider?

Cyanide poisoning

What are 3 options for treatment of cyanide poisoning ?

Hydroxocobalamin Sodium thiosulfate Nitrate

When do you consider hyperbaric treatment after carbon monoxide toxicity?

Pregnancy, acidosis, cardiac involvement or neurological involvement

What might have been ingested in a patient that appears drunk with oxalate crystals on urinalysis?

Ethylene glycol

What is seen in the first phase of ethylene glycol toxicity?

Nausea, tachycardia, hypertension, metabolic acidosis and calcium oxalate crystals with hypocalcemia

What is the cause of coma or cardio respiratory failure during phase 2 of ethylene glycol toxicity?

Large anion gap acidosis and hypocalcemia

What occurs in phase 3 of ethylene glycol toxicity and how is it treated?

Acute tubular necrosis with renal failure requiring dialysis

At what level is iron ingestion considered toxic?

40 mg/kg of elemental iron

What lab findings are consistent with iron toxicity?

``` 4hour post ingestion level > 350 WBC >15 Glucose> 150 Elevated LFTs Metabolic acidosis ```

What are 4 major multisystem effects of iron ingestion?

Metabolic acidosis Coagulopathy Cardiovascular collapse GI obstruction

What is the appropriate treatment for significant iron toxicity? What is not used for iron toxicity?

Defuroxamine chelation | Not charcoal as poor absorption

What are indications for iron chelation therapy?

Anion gap acidosis Iron >500 Significant number of pills seen on KUB

When can deferoxamine treatment be stopped?

When clinical improvement and urine no longer pink

What are classic presenting signs on a patient following ingestion of caustic substance?

Coughing, drooling, difficulty swallowing and chest pain

What is the initial management for suspected caustic substance ingestion?

Endoscopy within 48 hours

What is recommended for treatment of alkali ingestion?

Observation 6 hours Endoscopy if symptoms No activated charcoal as will inhibit endoscopic exam

What are PCBs and what can they cause?

Synthetic hydrocarbons that cause Pigmentation/rash, Cutting teeth early and Birthweight that is low

How can you differentiate varicella vs smallpox lesions?

Smallpox - starts in face and extremities with lesions in same stage. Chicken pox - starts centrally and spreads with lesions in varying stages.

What is a lesion that starts as an itchy papule that becomes bullous w central necrosis that is black and painless?

Cutaneous anthrax

What 5 medications are affected with use of St. John's wort and why?

``` OCPs Iron Digoxin Anticoagulants Antiretroviral drugs *induction of P450 increases drug elimination ```

How is echinacea believed to act? When is it contraindicated?

Acts by modulating cellular immunity | Contraindicated in patients on immunosuppressants

What 5 drugs can interact with ginseng?

``` Anticoagulants Anti platelets Steroids Hypoglycemic medications Diuretics ```

When should valerian root not be used?

In patients using alcohol or other sedating drugs

Isotretinoin and griseofulvin should be taken with what types of foods?

Fatty foods (the drugs are lipophilic)

Which 3 medications should not be taken with dairy products ?

Tetracycline Doxycycline Ciprofloxacin

When is steady state of a drug achieved?

After 4-5 half lives

What 4 drugs cause inhibitory effects on hepatic enzymes and thus increased toxicity of many drugs?

Erythromycin Ciprofloxacin Cimetidine Omeprazole

What 4 medications are considered potent enzymatic inducers which decrease the levels of many other medications ?

rifampin Phenobarbital Carbamazepine Phenytoin

What 2 drugs decrease bioavailability of calcium, iron and magnesium?

Cephalosporins and fluoroquinolones

What two drugs inhibit renal metabolism of digoxin and lead to toxicity?

Quinidine and amiodarone

What is the appropriate medication to give for a patient with adrenal insufficiency who requires stress dosing?

IV hydrocortisone

What are 4 major side effects of beta blockers ?

Sexual dysfunction Insomnia Bronchospasm Bradycardia

What type of drug is acetazolamide and how does it work?

Carbonic anhydrase inhibitor | Blocks teuptake of bicarb causing metabolic acidosis and alkaline urine

What are two major side effects of LASIX use?

Ototoxicity | Renal toxicity

What is the mechanism of action of loop diuretics and what electrolyte changes are seen?

Block absorption of Na and Cl Wasting of Ca, K and H Hypochloremic hypokalemic alkalosis

What is the appropriate dosing of activated charcoal?

0.5-1 g/kg (max 100g)