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Analgesia & sedation

Analgesia CRI · multi-modal

Build a multi-modal analgesia CRI: choose an opioid backbone and optionally add adjunct drugs. Each drug is computed independently with its own pump rate. Adjuncts: ketamine, lidocaine (dogs only), and dexmedetomidine.

How this calculator works

Pick one opioid (fentanyl, morphine, or hydromorphone) and optionally toggle on any combination of adjuncts: ketamine, lidocaine, and dexmedetomidine. Each selected drug gets its own card on the right with the pump rate to deliver the requested dose at the chosen bag concentration. The drugs are computed independently; each is a separate bag or syringe with its own pump rate, run through its own line.

Use the loading-dose panels on each card as starting boluses before beginning the CRI. Adjuncts add mechanisms on top of the opioid backbone: ketamine for NMDA antagonism and anti-windup, lidocaine for sodium-channel blockade and supraspinal anti-nociception (dogs only; cardiotoxicity in cats), dexmedetomidine for α₂-mediated opioid-sparing analgesia.

Phase 3 will add a combined-bag preparation mode for clinicians who want all selected drugs in a single bag (the MLK / DMLK workflow).

Patient
Species
Preparation

Combined bag covers the named-acronym workflows: MLK (morphine·lidocaine·ketamine), FLK (fentanyl·lidocaine·ketamine), DMLK (dex·morphine·lidocaine·ketamine), KL (ketamine·lidocaine), DLK (dex·lidocaine·ketamine), and any other one-bag· one-pump-rate combination the case calls for.

Opioid backbone

Standard ICU opioid for severe acute pain. Short half-life, quickly titratable, predictable cardiopulmonary effects.

Range: Dogs 2.0–10.0, Cats 2.0–10.0 ug/kg/hr

Syringe prep: 5 mL of 50 µg/mL stock + 45 mL 0.9% NaCl in a 50 mL syringe → 5 µg/mL (1:10 dilution). Run via syringe pump.

Pure mu-agonist with longer duration than fentanyl. Good choice for steady analgesia in dogs. Less favored in cats due to dysphoria.

Range: Dogs 0.1–0.4, Cats 0.05–0.1 mg/kg/hr

Syringe prep: 1 mL of 5 mg/mL stock + 49 mL 0.9% NaCl in a 50 mL syringe → 100 µg/mL (0.1 mg/mL). Run via syringe pump.

Pure mu-agonist similar to morphine but with less histamine release and less nausea. Good alternative to morphine when histamine release is a concern.

Range: Dogs 0.02–0.1, Cats 0.01–0.05 mg/kg/hr

Syringe prep: 1 mL of 2 mg/mL stock + 49 mL 0.9% NaCl in a 50 mL syringe → 40 µg/mL (0.04 mg/mL). Run via syringe pump.

Use the adjuncts alone: KL (ketamine + lidocaine), DLK (dex + lidocaine + ketamine), or single-adjunct CRI. For opioid-intolerant patients, opioid-shortage situations, or where the case calls for opioid-sparing analgesia.

Adjuncts

NMDA antagonist. Adds central anti-hyperalgesic effect on top of the opioid backbone. Useful for chronic, neuropathic, or wind-up-driven pain. Watch the unit (µg/kg/min vs mg/kg/hr) carefully; they differ by ≈60×.

Range: Dogs 2.0–10.0, Cats 2.0–10.0 ug/kg/min

Syringe prep: 1 mL of 100 mg/mL stock + 49 mL 0.9% NaCl in a 50 mL syringe → 2 mg/mL (2000 µg/mL). Run via syringe pump.

⚠ Not used in cats; will be skipped if the patient species doesn't match.

IV sodium-channel blocker. Adds supraspinal and spinal anti-nociception. Dog-only. Cats are uniquely sensitive to lidocaine cardiotoxicity at standard analgesic doses.

Range: Dogs 1.5–3.0 mg/kg/hr

Syringe prep: 10 mL of 20 mg/mL stock (2% WITHOUT epi) + 40 mL 0.9% NaCl in a 50 mL syringe → 4 mg/mL (4000 µg/mL). Run via syringe pump. Alternative: run undiluted 20 mg/mL stock at the slower pump rate.

α₂-agonist. Adds opioid-sparing analgesia and reduces ketamine metabolism. Caution: dose-dependent sedation and bradycardia. DMLK protocol uses 0.5 µg/kg/hr.

Range: Dogs 0.5–3.0, Cats 0.5–2.0 ug/kg/hr

Syringe prep: 0.4 mL of 500 µg/mL stock (Dexdomitor) + 49.6 mL 0.9% NaCl in a 50 mL syringe → 4 µg/mL. Draw the stock with a 1 mL (tuberculin) syringe for precision. Run via syringe pump.

Enter a patient weight to compute pump rates.

References

Sources

Dose ranges and protocols sourced from Plumb's Veterinary Drugs (current edition) and Lukasik V. 2015 (WSAVA Proceedings). Each drug's clinical background is on its fentanyl, hydromorphone, or ketamine learn page.