Naloxone HCl

What is this medication for?

• Opioid overdose/reversal, post-op opioid dysphoria (low-dose "microdosing"), adjunct in PEA during CPCR

How is it given?

Give exactly as your veterinarian prescribed — never change the dose or stop on your own unless your veterinarian has told you to.

• Titrate to effect rather than giving a full dose bolus whenever possible — full reversal abruptly removes analgesia and can precipitate a distressing, potentially dangerous excitatory reaction in a patient that was undergoing a painful procedure.

What if I miss a dose?

• Give it as soon as you remember — unless it is almost time for the next dose (then skip the missed one; never double up).
• Call your clinic if you miss more than one dose in a row.

Side effects — what should I watch for?

Effects listed as common in this handout

• Relatively free of adverse effects at usual doses in non-dependent patients

Worth a phone call to your veterinarian

• Acute pain/severe reaction (unusually fast heart rate, high blood pressure, excitement, arrhythmias) if reversing analgesia in a painful patient (Significant risk — reversal blocks endogenous opioids too)

⚠️ Contact your veterinarian or an emergency clinic IMMEDIATELY if you notice

• Reverses analgesia along with respiratory depression (Expected effect, not a true "adverse effect" but a major clinical consideration)

Before starting (or refilling), tell your veterinarian if your pet:

• has or has had: Hypersensitivity
• has or has had: Use cautiously in patients with pre-existing cardiac disease or suspected opioid dependence — may precipitate acute withdrawal; not reliable for reversing buprenorphine (partial agonist — may need 100× usual dose)

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Opioid partial agonists (butorphanol, buprenorphine)
  • Clonidine
  • Yohimbine

Storage and handling

Room temperature, protect from light. Do not mix with alkaline solutions or sulfite-containing solutions.

Good to know

• Titrate to effect rather than giving a full dose bolus whenever possible — full reversal abruptly removes analgesia and can precipitate a distressing, potentially dangerous excitatory reaction in a patient that was undergoing a painful procedure.
• Because naloxone's duration is often shorter than the opioid it's reversing, patients need close monitoring for re-drowsiness/re-depression and may require repeat dosing.
• Low-dose ("microdose") naloxone is a useful technique for managing opioid-induced dysphoria post-operatively without fully losing analgesic coverage.