What is the recommended buprenorphine dose and dosing interval for an otherwise healthy adult cat weighing 2–8 kg with moderate to severe acute pain or chronic pain when NSAIDs are contraindicated?

Buprenorphine Dosing for Feline Pain Management

For an adult cat (2-8 kg) with moderate to severe pain when NSAIDs are contraindicated, administer buprenorphine 0.02-0.04 mg/kg intravenously or intramuscularly every 6-8 hours for optimal analgesia. 1

Route-Specific Dosing Recommendations

Preferred Routes for Acute Pain

• Intravenous or intramuscular administration at 0.02-0.04 mg/kg is the gold standard for acute pain management in cats, providing reliable onset and duration of analgesia 1
• The subcutaneous route at standard clinical dosages does not provide adequate antinociception and should be avoided 1
• Buccal (oral transmucosal) administration has produced inconsistent results and is not recommended as a primary route 1

High-Dose Formulations for Extended Analgesia

• Doses up to 0.12-0.24 mg/kg subcutaneously using high-concentration formulations can provide prolonged antinociception lasting 24-30 hours in a single injection 2
• These higher doses have demonstrated no ceiling effect for analgesia and no adverse effects in clinical studies 2
• The traditional 0.01-0.02 mg/kg dosing range commonly cited is likely suboptimal for many cats with moderate to severe pain 3, 1

Pharmacokinetic Considerations Critical to Dosing

Delayed Onset Phenomenon

• Do not expect immediate pain relief after administration—buprenorphine exhibits negative hysteresis, meaning plasma concentrations are not correlated with immediate analgesic effect 1
• The pharmacokinetic-pharmacodynamic relationship is best described by a receptor association-dissociation model with delayed equilibration to the effect compartment 1
• Clinical analgesia typically begins 15-30 minutes after IV/IM administration, with peak effects at 1-2 hours 2

Duration of Action

• Standard doses (0.02 mg/kg) provide analgesia for approximately 6-8 hours 3, 1
• Higher doses (0.12-0.24 mg/kg) extend duration to 24-30 hours 2
• Elimination half-life varies dramatically with dose: 1.4-5.3 hours at 0.02 mg/kg versus 10-34 hours at higher doses (0.12-0.24 mg/kg) 2

Novel Transdermal Formulations

Extended-Duration Transdermal Solution

• A transdermal buprenorphine solution (TBS) provides 4 days of analgesia from a single preoperative dose 4, 5
• Approved dosing: 8 mg for cats 1.2-3 kg; 20 mg for cats >3-7.5 kg (equivalent to 2.7-6.7 mg/kg) 5
• Applied topically to unclipped dorsal cervical skin with peak plasma concentrations occurring at 2-12 hours post-application 4
• Absolute bioavailability is 16% with terminal half-life of approximately 65 hours due to flip-flop kinetics 4
• Safety demonstrated at 3X the approved dose with minimal adverse effects 5

Important Clinical Caveats

Individual Variability

• Significant individual variability in response to buprenorphine has been documented—some cats may not achieve sufficient analgesia even at appropriate doses 1
• Pain assessment using validated feline pain scales is essential to determine if additional or alternative analgesia is needed 1

Expected Physiological Effects

• Transient sedation, mydriasis, and euphoria are normal within 4 hours of administration 4, 5
• Body temperature may increase 0.6-0.9°C above baseline (normal 37.4-37.8°C) and persist through the duration of effect 4, 5
• These effects diminish with repeated dosing due to accommodation 5

Safety Profile

• No ceiling effect for analgesia has been demonstrated at clinical doses in cats, contrary to concerns extrapolated from human medicine 1, 2
• Respiratory depression is minimal even at doses up to 0.24 mg/kg 2
• Constipation occurs transiently but at similar rates to placebo-treated cats 5

Dosing Algorithm for Clinical Practice

For acute moderate-to-severe pain:

1. Administer 0.02-0.04 mg/kg IV or IM initially
2. Reassess pain at 1-2 hours (peak effect window)
3. Redose every 6-8 hours as needed based on pain scores

For postoperative pain requiring extended coverage:

1. Consider high-dose formulation (0.12-0.24 mg/kg SC) for 24-30 hour duration
2. Or apply transdermal solution (8-20 mg based on weight) preoperatively for 4-day coverage

For chronic pain:

1. Standard dosing every 8 hours is appropriate (0.02 mg/kg IV/IM)
2. Transdermal formulation may improve compliance for home management