Assessment and Management of Pain

Listed below are procedures that are frequently presented with rodent and rabbit protocol proposals. The intensity and duration of post-surgical post-procedural pain will vary according to a number of factors such as the invasiveness of procedure, degree of tissue trauma, surgical time, skill of the surgeon and the tissues or organs that will be involved.

Procedures and their Potential to Cause Pain:

Pain Potentional
Minimal to Mild Pain Mild to Moderate Pain Moderate to Severe Pain
Catheter implantation Minor laparotomy incisions Major laparotomy / organ incision
Tail clipping Thyroidectomy Thoracotomy
Ear notching Orchidectomy Heterotopic organ transplantation
Superficial tumor implantation C-section Vertebral procedures
Orbital sinus venotomy Embryo transfer Burn procedures
Superficial lymphadenectomy Hypophysectomy Trauma models
Ocular procedures Thymectomy Orthopedic procedures
Multiple ID antigen injections    
Intracerebral electrode implantation    
Vasectomy    
Vascular access port implantation    

Non-Pharmacologic Postoperative Support Methods for Mice and Rats:

Non-Pharmacologic Postoperative Support Methods for Mice and Rats
Minimal to Mild Mild to Moderate Moderate to Severe
Wound care Wound care Wound care
House singly until ambulatory Soft, absorbent bedding, nest material Soft, absorbent bedding, nest material
  Modified food and water access Modified food and water access
  House singly until ambulatory Increased food palatability
  Supplemental heat Supplementary heat and hydration, SC or IP
    House singly until ambulatory

Signs of Pain and Distress in Mice:

Signs of Pain and Distress in Mice
Mild to Moderate Pain/Distress Signs Severe or Chronic Pain/Distress Signs
  • Eyelids partially closed
  • Changes in respiration
  • Rough hair coat
  • Increased vibrissal movements
  • Unusually apprehensive or aggressive
  • Possible writhing, scratching, biting, self-mutilation
  • Hunched posture
  • Sudden running movements (escape)
  • Aggressive vocalization when handled or palpated
  • Guarding
  • Weight loss (decreased appetite)*
  • Dehydration
  • Incontinence
  • Soiled hair coat
  • Eyes sunken, lids closed
  • Wasting of muscles on back
  • Sunken or distended abdomen
  • Decreased vibrissal movements
  • Unresponsive
  • Separates from group
  • Hunched posture
  • Ataxia, circling
  • Hypothermia
  • Decreased vocalization
  • Reduced rearing

*May see weight loss even with moderate pain/distress.

Suggested Pharmacologic Methods for Mice:

Suggested Pharmacologic Methods for Mice
Minimal to Mild Mild to Moderate Moderate to Severe
Local anesthesia
Lidocaine /Bupivacaine		 Lidocaine / Bupivacaine
(adjunct to systemic analgesic)		 Lidocaine / Bupivacaine
(adjunct to systemic analgesic)
Butorphanol
1-5 mg/kg, SC
q 4 h		 Buprenorphine
0.05-0.1 mg/kg, SC
q 8-12 h		 Buprenorphine*
0.05-0.1 mg/kg, SC
q 8-12 h
Carprofen
2.5-5.0 mg/kg, SC
Once		 Carprofen
2.5-5.0 mg/kg, SC
q 24 h		 Carprofen*
2.5-5.0 mg/kg, SC
q 24 h
    Morphine
2-5 mg/kg SC
q 2-4 h

*Severe pain may be better addressed by the addition of a NSAID to an opioid. This multimodal approach allows for action at different points on the pain pathways, and will allow for a lower dosage of both components. Buprenorphine, alone, is recommended for only moderate pain management.


Signs of Pain and Distress in Rats:

Signs of Pain and Distress in Rats
Mild to Moderate Pain/Distress Signs Severe or Chronic Pain/Distress Signs
  • Eyelids partially closed
  • Porphyrin staining around eyes, nose
  • Rough hair coat and/or hair loss
  • Increased aggression (towards humans and cage mates)
  • Reduced exploratory behavior
  • Aggressive vocalization when handled
  • Licking, biting and/or scratching
  • Guarding
  • Eyes closed
  • Poor skin tone
  • Muscle wasting along back
  • Dehydration
  • Weight loss (decreased appetite)*
  • Incontinence
  • Soiled hair coat
  • Depressed/unresponsive
  • Sunken or distended abdomen
  • Self-mutilation
  • Recumbent position with head tucked into abdomen
  • Decreased vocalization
  • Hypothermia
  • Reduced rearing
  • Eating of bedding

*May see weight loss even with moderate pain/distress.

Suggested Pharmacologic Methods for Rats:

Suggested Pharmacologic Methods for Rats
Minimal to Mild Mild to Moderate Moderate to Severe
Local anesthsia
Lidocaine		 Local anesthesia
Lidocaine / Bupivacaine
(adjunct to systemic analgesic		 Local anesthesia
Bupivacaine
(adjunct to systemic analgesic)
Butorphanol
2 mg/kg, SC
once		 Buprenorphine
0.05 mg/ kg, SC
q 6-12 h		 Buprenorphine*
0.05 mg/kg, SC
q 6-8 h
Carprofen or ketoprofen
2.5-5 mg/kg, SC
once		 Carprofen or ketoprofen
2.5-5 mg/kg, SC
q 24 h		 Carprofen or ketoprofen*
2.5-5 mg/kg, SC
q 24 h
Meloxicam
l mg/kg, SC
once		 Meloxicam
1-2 mg/kg, SC
q 24 h		 Meloxicam*
1-2 mg/kg, SC
q 24 h
    Morphine
2.5-10 mg/kg
q 2-4 h
Severe Pain

*Severe pain may be better addressed by the addition of a NSAID to an opioid. This multimodal approach allows for action at different points on the pain pathways, and will allow for a lower dosage of both components. Buprenorphine, alone, is recommended for only moderate pain management.

Clinical Assessment of Post-Procedural Pain in Rabbits:

  • reduced activity
  • failure to groom
  • reduced food and/or water intake
  • squint-eyed
  • pale eyes (if albino)
  • changed posture, tucking of abdomen, tensing of muscles
  • guarding, attempting to hide, or aggressiveness
  • grinding of teeth

Non-Pharmacologic Pain Management Recommendations:

Non-Pharmacolgic Pain Management Recommendations for Rabbits
Minimal to Mild Mild to Moderate Moderate to Severe
Wound care Wound care Wound care
Soft, absorbent bedding Soft, absorbent bedding Soft, absorbent bedding
    Modified food and water access
    Increased food palatibility
    Hydration, SC or IP
    Supplemental heat

Suggested Pharmacologic Methods for Rabbits:

Suggested Pharmacologic Methods for Rabbits
Minimal to Mild Mild to Moderate Moderate to Severe
Local anesthetic
Lidocaine /Bupivacaine		 Local anestethic
Bupivacaine
(adjunct to systemic analgesics)		 Local anesthetic
Bupivacaine
(adjunct to systemic analgesics)
Ketoprofen
3 mg/kg, SC
once		 Buprenorphine
0.01-0.05 mg/kg, SC, IM, IV
6-12 h		 Buprenorphine
0.05 mg/kg, SC, IM, IV
6-12 h
Butorphanol
0.1-0.5 mg/kg, IM, IV
q 4 h		 Butorphanol
0.1-0.5 mg/kg, IM, IV
q 4 h		 Morphine
2-5 mg/kg, SC
q 2-4 h
Carprofen
4.0 mg/kg, SC
1.5 mg/kg, PO
once		 Carporfen
4.0 mg/kg, SC,
q 24 h
1.5 mg/kg, PO,
q 12 h		 Fentanyl patch
25 µg/h
Transdermal q 72 h
Meloxicam
0.2-0.3 mg/kg, SC, PO
once		 Meloxicam
0.3-1.5 mg/kg, PO
q 24 h		  

Updated June 18, 2007 by SAK