Opioid Antagonists

A patient who has severe pain presents to the emergency department following an accidental overdose of morphine 20mg/ml concentrate (oral). Naloxone is administered with spontaneous return of consciousness. What problem can the ACNP anticipate?

Because naloxone blocks all opioid receptors, the analgesic effect will be blocked. The pain will return and will likely be quite severe.

Opioid Antagonists

Opioid antagonist compete with opioid agonists. They block opioid receptors so that they cannot be stimulated by opioid drugs. Examples include naloxone (Narcan) - used to reverse opioid overdose naltrexone (ReVia) - used to help prevent resumption of opioid street drug use in people who are addicted but have stopped using

Naloxone has a half life of 60-90 minutes with a duration of action of 45 minutes. Why is this a concern?

The duration of action of opioids is longer than the duration of action of naloxone. Although the patient may have a good initial response, the shorter duration of action will likely require readministration to prevent continued overdose effects.

A patient who has an opioid addiction and dependence presents to the emergency department after overdosing on drugs purchased on the street. What problem can the ACNP anticipate?

The patient is likely to experience withdrawal symptoms so the ACNP needs to prepare for this eventuality.

Naloxone (Narcan)

Used primarily to reverse respiratory depression and unresponsiveness caused by opioid OD. Specific for opioid receptors Blocks all opioid receptors (μ, κ, δ, σ)