History and exam

Key diagnostic factors

common

history of opioid use disorder and dependence

People who misuse opioids on a regular basis or who are addicted to opioids are at risk of overdose.

Regular users of opioids who have had a period of abstinence from use (e.g., on release from prison or discharge from a treatment program) are at increased risk of overdose.

miosis

Constricted pupils usually seen.

bradypnea

Respiratory rate of <12 breaths/minute in an unconscious patient presenting via emergency medical services best predicts a response to naloxone and overdose.[50]

altered mental status

Including drowsiness and sleepiness.

dramatic response to naloxone

Diagnostic of opioid overdose, although lack of response does not preclude overdose. Many new synthetic opioids need higher doses of naloxone.[51]

Other diagnostic factors

common

fresh needle marks

Suggestive of recent intravenous injection.

drug paraphernalia nearby

Such as syringes or smoking equipment.

decreased gastrointestinal motility

Signs and symptoms include nausea and vomiting, constipation, and abdominal pain.

old track marks on arms and legs

Evidence of previous intravenous drug use may suggest recent injection.

uncommon

pulmonary rales

May indicate acute respiratory distress syndrome.

frothy pink sputum

May indicate acute respiratory distress syndrome.

seizures

Can occur with overdose of meperidine, propoxyphene, and tramadol.

dysrhythmias

Can be caused by sodium channel blockade with propoxyphene and can be associated with significant respiratory compromise.

Risk factors

strong

history of prescribed opioids

Observational studies suggest that opioid therapy for chronic pain is associated with increased risk for overdose and opioid abuse.[3][25]​​ Concurrent use of benzodiazepines​​, previous history of overdose, multiple prescribers or dispensing pharmacies, history of fentanyl prescription, current substance use disorder, and a history of a mental health diagnosis are all also associated with increased risk of overdose in those prescribed opioids.[26][27]

opioid use disorder and dependence

People with opioid use disorder are at risk of overdose. Withdrawal symptoms during abstinence in opioid-tolerant people reinforce use of the drug, and they often need higher doses to obtain the desired drug effect. Opioids are often obtained from untested, nonpharmaceutical sources and the purity may vary greatly, making it difficult to know the exact dose of the drug and avoid an overdose.

recent abstinence in chronic users

Regular users of opioids who have had a period of abstinence from use (e.g., on release from prison or discharge from a treatment program) are at increased risk of overdose. Tolerance to opioids is lost during periods of abstinence, making it difficult to judge the amount of opioid required to obtain a desired effect. The risk is increased further with the variation in purity of illicit opioids.[22][28]

taking opioids by injection

Rapid effects of high doses cause respiratory depression, particularly when injecting for the first time.[29]

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