Standard on Pain Identification and Post-Operative Analgesia


University of North Carolina at Chapel Hill Standard on Pain Identification and Post-Operative Analgesia



The standards and procedures described below provide guidance to all researchers and animal handlers regarding identification of pain in animals and appropriate analgesia for post-operative and Pain Category D procedures to prevent pain.


This Standard applies to all personnel engaged in the care and husbandry of animals and laboratory members administering post-operative analgesia and/or performing post-operative monitoring.

The University of North Carolina at Chapel Hill ("UNC-Chapel Hill" or "University") Institutional Animal Care and Use Committee (IACUC) expects that anyone involved in animal work at the University will comply with this Standard. Requests for exceptions to this Standard must be reviewed and approved by the IACUC.


In order to alleviate pain and/or distress post-operatively, the IACUC requires the administration of analgesics for all survival surgeries. Selection of the appropriate analgesic agent(s) should be based on the type of surgical procedure, be provided for a minimum of 24 hours to 48 hours based on species and type of procedure (see DCM formulariesand continued longer if the animal is displaying any symptoms associated with pain. Those in contact with animals post-operatively should be familiar with the potential signs associated with pain or distress to ensure analgesia is provided as needed (refer to table and links at the end of this standard as well as species-specific literature).

Dependent on the procedure, different forms of anesthesia may be utilized to alleviate pain. A major surgery may require the administration of a narcotic agent such as Buprenorphine (Buprenex®) for adequate pain control and/or relief. Non-steroidal anti-inflammatory agents such as carprofen or meloxicam may be suitable for major or minor surgeries. Combinations of analgesics may be recommended, in order to provide multimodal analgesia, particularly for major surgeries. Depending on the procedure, administration of a local anesthetic, such as lidocaine or bupivacaine, may aid in pain reduction.

Note: Sedatives (able to reduce irritability/excitement) and anxiolytics (able to prevent or reduce anxiety) do not relieve pain. However, they may be used in conjunction with appropriate analgesics to provide an appropriate level of restraint or surgical anesthesia..

The US Department of Agriculture and Public Health Service policies require proper documentation of animal care and use to assess compliance with research protocols and clinical care procedures. UNC-Chapel Hill specifically requires the use of the pink "Post-Operative Monitoring/Analgesia" cards on all post-operative cages receiving monitoring or analgesia. Cards must be kept on the cage during the specified monitoring or analgesia period described within the protocol. The lab may utilize these cards as the required documentation for all observations and treatments performed during the post-operative period. Dates and times (including AM/PM) of all time-sensitive observations or treatments (post-operative evaluations, pain medication) must be recorded. If these cards are the only documentation of the post-operative analgesic administration, they must be kept with the lab’s surgery records for review and made available during inspections.

Written records are a standard form of documentation which verify experimental procedures and protocol compliance. As part of an effective animal care and use program, research personnel working with animals must develop and maintain accurate study records. Specific parameters (body weight measurements, clinical signs, tumor size, etc.) outlined in an approved protocol must be documented with attention given to the type of monitoring, frequency, and duration outlined in the approved protocol (e.g., the statement in the approved protocol "We will monitor the animal daily after surgery," requires written documentation of the daily observation.)

Regulatory and accrediting agencies expect proper documentation of animal care and use as a means for the institution to ensure compliance with research protocols and clinical care procedures. The extent of records varies based on the nature of the procedure. However, at a minimum, records of the procedure must consist of:

  • Animal /cage/group ID;
  • date of procedure;
  • type of procedure;
  • anesthetics/analgesics used (dose, route, and time);
  • anesthesia chart (verification of toe pinch);
  • drugs given (dose, time); and
  • general procedures (e.g., intubation, beginning and end of surgery, etc.).

See the UNC IACUC Rodent Anesthesia/Analgesia/Procedure Record.


Requests for exceptions to this Standard must be reviewed and approved by the IACUC.

Definitions, Table and Links for Reference

  • AWA: Animal Welfare Act
  • ACLAM: American College of Laboratory Animal Medicine
  • ILAR: Institute for Laboratory Animal Research
  • NIH: National Institutes of Health
  • Distress: the biological responses an animal exhibits in an attempt to cope with a threat to its homeostasis.
  • Non-survival Surgery: Surgical procedure where an animal is euthanized before recovery from anesthesia.
  • Major Survival Surgery: Surgical procedure that penetrates and exposes a body cavity. This also includes procedures that induce substantial impairment of physical or physiologic functions (such as laparotomy, thoracotomy, joint replacement, and limb amputation), or involves extensive tissue dissection or transection.
  • Minor survival surgery: does not expose a body cavity and causes little or no physical impairment.
Table 1: Potential Signs Associated with Pain or Distress in Rats, Mice, and Rabbits
Potential Sign Mice Rats Rabbits
Decreased Food and Water Consumption X X X
Weight Loss/ decreased body condition X X X
Self-Imposed Isolation/Hiding X X X
Self-Mutilation, Gnawing at Limbs X X X
Rapid Breathing X X X
Open Mouth Breathing X X X
Abdominal Breathing X X X
Grinding Teeth   X X
Biting/Growling/Aggression   X X
Increased/Decreased Movement X X X
Unkempt Appearance (Erected, Matted, or Dull Haircoat) X X X
Abnormal Posturing/Positioning (e.g., Head-Pressing, Hunched Back) X X X
Restless Sleep     X
Tearing (Including Porphyria), Lack of Blinking Reflex   X X
Dilated Pupils     X
Muscle Rigidity, Lack of Muscle Tone X X X
Dehydration/Skin Tenting/Sunken Eyes X X X
Twitching, Trembling, Tremor (non-seizure-related) X X X
Vocalization (Rare) X X X
Redness or Swelling Around Surgical Site X X X
Increased Salivation     X

Please see chapter 3 of the following document for additional species-specific information on pain assessments in laboratory animals:

The following links provide pictorial examples of pain in rats, mice, and rabbits:

Related Requirements

External Regulations and Consequences

University Policies, Standards, and Procedures

Contact Information

Policy Contact
Subject Contact Telephone Email
Veterinary Consult DCM Vet Services 919-966-2609  
IACUC Protocol OACU 919-966-5569

Important Dates

  • Effective Date and title of Approver: January 2011; UNC IACUC
  • Revision and Review Dates, Change notes, title of Reviewer or Approver: April, 2014, June 2018; UNC IACUC

Approved by: UNC IACUC

100% helpful - 1 review


Article ID: 132204
Thu 4/8/21 9:26 PM
Fri 4/19/24 9:42 AM
Effective Date
If the date on which this document became/becomes enforceable differs from the Origination or Last Revision, this attribute reflects the date on which it is/was enforcable.
11/14/2022 12:00 AM
Issuing Officer
Name of the document Issuing Officer. This is the individual whose organizational authority covers the policy scope and who is primarily responsible for the policy.
Issuing Officer Title
Title of the person who is primarily responsible for issuing this policy.
Vice Chancellor
Last Review
Date on which the most recent document review was completed.
10/18/2023 12:00 AM
Last Revised
Date on which the most recent changes to this document were approved.
11/14/2022 12:00 AM
Next Review
Date on which the next document review is due.
10/18/2024 12:00 AM
Date on which the original version of this document was first made official.
09/09/2019 12:01 PM
Responsible Unit
School, Department, or other organizational unit issuing this document.
Research-Institutional Animal Care & Use Committee