Tox: Opioids

Question 1

Receptors stimulated by opioids

Answer 1

mu, kappa, delta receptors in the CNS, spinal cord and GI tract

Question 2

Classic triad of opioid overdose

Answer 2

CNS depression, respiratory depression, miosis

Question 3

Symptoms of opioid toxicity (outside of classic triad)

Answer 3

CVD: bradycardia, orthostatic hypoTN, peripheral vasodilation.
GI: reduced motility, reduced gastric acid secretion, increased anal sphincter tone.
Otologic: sensorineural hearing loss with prolonged use.
Metabolic: hypoglycemia, hypothermia.
Neuro: seizures with meperidine.
Pulmonary: non-cardiogenic pulmonary edema.

Question 4

Duration of action of naloxone

Answer 4

30-90 min if IV/SQ/IM, 2hrs if IN

Question 5

How long should patients be observed after naloxone given?

Answer 5

6 hrs for all-comers, 24 hrs if child

Question 6

Complications of opioid overdose

Answer 6

Aspiration/anoxic brain injury.
Rhabdo/compartment syndrome if prolonged immobilization.
Withdrawal syndrome.

Question 7

How are narcan drips dosed

Answer 7

Infusion rate should be started at 2/3 of the naloxone dose that reversed the patients symptoms.
E.g. if initial bolus which reversed symptoms was 2mg, start infusion at 1.3mg/HR.

Question 8

When should a narcan drip be considered

Answer 8

If an opioid effect is expected to be prolonged, e.g.:

1) massive overdose
2) suicide attempt with opioid
3) methadone overdose