Short-acting opioid infusions (alfentanil / remifentanil / sufentanil)

What is this medication for?

• Intraoperative analgesia CRIs (anesthesia-sparing, rapid titration); alfentanil/sufentanil premed-induction adjuncts; sufentanil epidural; emergency acute pain (sufentanil)

How is it given?

This medication is normally given by your veterinary team (in clinic or hospital).

• Remifentanil's esterase clearance = the operating-room favorite: minute-by-minute titration with zero accumulation — but analgesia vanishes the second the pump stops; bridging analgesia must precede discontinuation.

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

• Bradycardia, low blood pressure (Infusion-titration effects)
• Chest-wall rigidity (high-dose alfentanil-class) (Anesthesia-team event)
• Dysphoria on wake-up (Transition-to-oral era issue)

Worth a phone call to your veterinarian

• Any new symptom that worries you.

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

• Respiratory depression/stopped breathing (induction doses) (Expected — ventilation ready)

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

• has or has had: Obese patients: dose on LEAN body weight (Plumb note); MAOI co-use cautions; anesthetist-administered only

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Propofol/inhalants
  • Naloxone
  • Benzodiazepines

Storage and handling

C-II controlled; dilute per protocol; label lines/pumps explicitly (micrograms/kg/min math errors are the classic incident).

Good to know

• Remifentanil's esterase clearance = the operating-room favorite: minute-by-minute titration with zero accumulation — but analgesia vanishes the second the pump stops; bridging analgesia must precede discontinuation.
• micrograms/kg/MIN vs micrograms/kg/HOUR unit confusion is a named, recurring medication error in this class (Plumb flags it explicitly for remifentanil) — the pharmacy double-check point.
• Sufentanil epidural (0.7–1 micrograms/kg) = the neuroaxial niche of the trio.