Pharm - Tx of OD (part 2)

Question 1

mg/kg of iron in ferrous sulfate, gluconate, fumarate

Answer 1

• ferrous sulfate: 60-65 mg tab = 20% elemental iron
• ferrous gluconate: 12% elemental iron
• ferrous fumarate: 33% elemental iron

Question 2

Identify whether or not the ingestion is considered a serious toxicity

Answer 2

• Minimal toxicity: < 350 mcg/dL
• Mild-moderate GI symptoms: 350-500 mcg/dL
• Serious systemic toxicity: > 500 mcg/dL
• Significant morbidity/mortality: > 1000 mcg/dL
• > 60 mg/kg considered serious toxicity

Question 3

Identify the 5 phases of iron overdose and the expected timeframe of each

Answer 3

• GI phase:
o 30 minutes-6 hours after ingestion → direct injury to GI mucosa (V/D, abdominal pain, hematemesis, melena, shock)
o Vomiting most sensitive indicator
• Latent, relative stability phase
o 6-24 hours after ingestion
• Shock and metabolic acidosis:
o 6-72 hours after ingestion → CV toxicity (shock, pallor, tachycardia, hypotension), coagulopathy, jaundice, coma
• Hepatotoxicity/hepatic necrosis:
o 12-96 hours after ingestion → liver particularly vulnerable to iron so hepatocytes have high metabolic activity and liver failure is 2nd MCC of death from iron poisoning
o If die, usually in this stage
• Bowel obstruction:
o 2-8 weeks after ingestion → occurs as result of GI scarring (possible V)

Question 4

Identify the antidote of choice for an iron overdose

Answer 4

IV deferoxamine

Question 5

Indications for use of IV deferoxamine

Answer 5

• Severe sx: hypovolemia, shock, lethargy, coma, persistent n/v
• anion gap metabolic acidosis
• peak serum concentration >500 mcg/dL
• significant # pills on radiograph

Question 6

Identify the classic signs of an opioid overdose

Answer 6

• Depressed mental status
• Decreased respiratory rate
• Decreased tidal volume
• Decreased bowel sounds
• Miotic pupils (constriction due to parasympathetic stimulation)

Question 7

best predictor of an opioid poisoning

Answer 7

RR < 12

Question 8

physical exam findings that are consistent with an opioid poisoning

Answer 8

• Respiratory rate: decreased, perform pulse ox, hypercapnia can be present
• HR: normal to low
• BP: hypotensive due to histamine release
• Hypothermia: measure temp due to environmental exposure/impaired thermogenesis
• Pupil exam: miosis
• Mental status: euphoria to coma, seizures secondary to tramadol or meperidine due to hypoxia
• Head trauma
• Skin exam: track marks
• Pulmonary findings: rales (aspiration/ARDS)

Question 9

lab evaluation of the person with a suspected opioid overdose

Answer 9

• Obtain serum glucose concentration
• Acetaminophen level
• Serum creatinine phosphokinase
• EKG
• Chest X-ray

Question 10

Identify the antidote of choice for an opioid overdose.

Answer 10

Naloxone

Question 11

Identify the dose based on patient presentation for an opioid overdose.

Answer 11

• When spontaneous ventilations present: 0.04-0.05mg titrated upwards every few minutes until RR is ≥ 12
• Apneic patients: 0.2-1.0mg
• Cardiorespiratory arrest: 2mg

Question 12

Identify the goal of naloxone in the tx of opioid OD

Answer 12

adequate ventilation, not normal level of consciousness!