What is Chemical Restraint in Animals?

Chemical restraint is often necessary when dealing with both domestic and exotic animals. In the former, this generally includes routine procedures on companion, work and performance large and small animals. In the latter, it includes both major and minor medical interventions, as well as the capture and/or immobilization of wild animals in the field or in captivity. The needs for chemical restraint in wild animals vary, and include wildlife management, conservation and medical treatment, among others.

Chemical restraint through the use of veterinary drugs is typically administered or overseen by a veterinarian. In the U.S., federal, state and local laws regulate the use of the drugs used in chemical restraint.

Types of Chemical Restraint Used in Animals

In general, there are two types of chemical restraint used in animals:

Sedation—This method, using sedatives and/or tranquilizers, is used to reduce the responsiveness of an animal without necessarily producing unconsciousness. With sedation, an animal may still react to certain stimulation.1,2

Anesthesia—Anesthetic drugs are used to completely immobilize an animal. This method is typically used may be used if the nature of a procedure requires additional control or involves invasive procedures such as surgery.

The use of sedative drugs may precede the use of anesthetic drugs, depending on the circumstances and requirements of procedures and animal handling personnel.

Tranquilizing drugs (sedatives) are also used as surgical premedications (as a precursor to anesthesia) in companion and exotic animals. These drugs include various classes, such as:

• Opioids
• Tranquilizers
• Anticholinergics
• Dissociatives
• Alpha-2 agonists (α-2 agonists)

Depending on the venue and circumstance, these agents are delivered by injection, blow pipe or dart gun.

Anesthetic drugs are used in cases where prolonged invasive procedures such as surgery are indicated.2 Maintenance anesthesia is accomplished via inhalant agents such as isoflurane or sevoflurane after an animal has been stabilized with other agents (sedative drugs, or agents such as thiopental or propofol).

The effects of chemical restraint vary depending on the method, dosage and levels of stimulation experienced by the animal. 1Reversal agents are available for certain classes of sedative and anesthetic agents. It should be noted that it may be necessary for chemical restraint to remain effective after performing procedures on exotic animals in the field. Whenever possible, a suitable and safe recovery area should be provided for the restrained animal to remain in until it has sufficiently recovered from the effects of sedatives/anesthetics.

Interested in learning more about safe capture? The San Diego Zoo now offers courses in safe capture techniques and best practices. Learn reliable, safe, and effective techniques for the species you work with and the scenarios you encounter!