Anesthesia Guidelines: Hamsters

Find guidelines for hamster anesthesia, including anesthetic drugs and procedures.

Research Animal Resources (RAR) veterinary staff designed these guidelines to be general recommendations, not an inclusive list of all possible drug combinations that can be used in hamsters. Consequently, guidelines do not reference specific research-associated concerns. 

If you have questions about using anesthetics for your particular situation, please work with your area veterinarian to develop the most effective anesthetic plan.


How to use anesthesia

Animals may be anesthetized for surgery, non-surgical procedures that may be painful, or non-painful procedures that require immobilization. Anesthesia causes the loss of feeling in all or part of the body, with or without loss of consciousness.

Anesthetic drugs can be administered parenterally or by inhalation. The choice of anesthetic agent will depend on the procedure to be performed, research aims, and other factors such as animal age. Consult your area veterinarian with questions about drug selection.


General guidelines and considerations for hamster anesthesia

Acclimation

A one-week acclimation period is recommended for all animals to prevent stress-induced disease.

Fasting

Pre-anesthetic fasting is usually not necessary for hamsters due to their inability to vomit. However, if fasting is employed, limit to no more than two to three hours due to the high metabolic rate of small rodents. Never restrict water.

Eye protection

Hamster eyes remain open under anesthesia. This can lead to corneal drying and trauma. Apply ophthalmic ointment (e.g., Paralube® or Lacrilube®) to eyes if:

  • The anesthetic event lasts longer than five minutes.
  • Anesthesia is being delivered by facemask. 

Monitoring

Regardless of the anesthetic administered, monitor hamsters under anesthesia to avoid excessive depression of cardiac and respiratory functions, or insufficient anesthesia. Parameters that can be monitored in an anesthetized hamster without specialized equipment include:

  • Anesthetic depth: Toe pinch. 
  • Respiratory rate and pattern: The normal undisturbed rate is ~30-135/min, a slow rate drop of 50% is acceptable during anesthesia.
  • Mucous membrane color: Should be pink, not blue or gray.
  • Body temperature: Can be monitored with a rectal thermometer.
  • Oxygen saturation and heart rate: Can be monitored using a specialized rodent pulse oximeter, and should be greater than 95% and between 300-550 beats/minute, respectively. 

Heat support

All species are at risk for hypothermia while under anesthesia. Hamsters are particularly susceptible due to their high body surface area to body mass ratio. Hypothermia induces significant physiological stress on animals that can prolong recovery and potentially be fatal. Guidelines:

  • Provide supplemental heat during all anesthetic events. Supplemental heat sources include circulating water blankets, electric heating pads, and commercial products that can be warmed in a microwave.
  • Never place the animal directly on the heat source.

Fluid support

Consider providing warm subcutaneous (SQ) or intraperitoneal (IP) fluids, particularly for prolonged anesthetic events or animals that are ill, aged, or debilitated.

Recovery

Continue to monitor animals until they are fully recovered. Guidelines:

  • Recover animals on paper towels (without bedding) in a clean cage. This minimizes the risk of tracheal obstruction or pneumonia.
  • Recover anesthetized animals alone in a cage.
  • Continue to provide supplemental heat during recovery.
  • When the animal is ambulatory, return it to the home cage with immediate access to food and water.

Contact your area veterinarian with questions or for more information.


Anesthetic drugs and procedures

Inhaled anesthetics

Inhaled anesthetics

Injectable anesthetics

Injectable anesthetics

Combined ketamine/xylazine is the preferred injectable anesthetic in hamsters. Other commonly used injectable agents are listed below.

Key considerations:

  • Hamsters vary significantly in their sensitivity to various anesthetics. Age, body composition, strain, health status, genetic manipulation, and sex are just a few of the factors that can contribute to anesthetic sensitivity. The following doses are general guidelines that may vary significantly based on the aforementioned factors. When adding anesthetics to your protocol, it is advisable to provide a range to allow titration for the specific needs of each animal.
  • Intramuscular (IM) injections are not recommended in hamsters as complications such as tissue irritation, lameness, and self-mutilation can result.

Ketamine + Xylazine (Rompun®) – recommended

Dose: Ketamine: 100-200 mg/kg + Xylazine: 10mg/kg
Route: Intraperitoneal (IP)
Duration of anesthesia: 30-60 minutes
Comments: Thermal support is crucial. To prolong anesthesia, supplement with 1/3 dose of ketamine only. Xylazine can be reversed with 1 - 2 mg/kg yohimbine IP or 0.1 - 1.0 mg/kg atipamezole IP/SQ.


Pentobarbital (Nembutal®)

Dose: 50-90mg/kg 
Route: IP
Duration of anesthesia: 30-60 minutes
Comments: Causes respiratory depression; narrow margin of safety. Use with caution.


Telazol + Xylazine

Dose: Telazol: 20-30 mg/kg + Xylazine: 10 mg/kg
Route: IP
Duration of anesthesia: 30-60 minutes

Local anesthetics

Local anesthetics

Local anesthetics are a type of injectable anesthetic. Local anesthetics block nerve impulses by specifically binding the voltage‐gated Na+ channel in the nerve cell membrane.

Routes of administration include topical to mucous membranes (nose, eye, etc.), or injected directly into tissues and around nerve bundles.

Key considerations:

  • Administration of local anesthetics prior to the painful stimulus (e.g., incision) would be considered an adjunct analgesic to opioid and NSAID analgesics. 
  • Use as a primary analgesic is discouraged due to the short duration (hours).
  • Lidocaine has a quick onset (1-2 minutes), but is short acting (1-2 hours). Bupivacaine is slow onset (10-15 minutes), but is long acting (4-8 hours). When used in combination (lidocaine plus bupivacaine in the same syringe) local anesthesia can be fast onset with a relatively long duration of action.
  • For rodent use, dilute 1‐2% lidocaine to 0.5%, and 0.5% bupivacaine to 0.25%, to allow for feasible volumes to infuse at the incision site (1% solution is equal to 10 mg/mL).

Lidocaine

Dose: 2-4 mg/kg (0.4 mL/kg of a 1% solution)
Route: Local infiltration
Comments: Do not exceed 7 mg/kg total dose. Rapid onset, short duration


Bupivacaine

Dose: 1-2 mg/kg (0.4-0.8 mL/kg of a 0.25% solution)
Route: Local infiltration
Comments: Do not exceed 6 mg/kg total dose. Slower onset, longer duration

References for these guidelines are available by request.