MKB Kit Dosages and Usage

The management of large hoofstock in the wild or on preserves often necessitates live capture of specific individuals, and chemical immobilization is generally the most effective method for capturing these animals. Selective capture of deer and other large cervids may be necessary for research such as to attach or remove radio-transmitters, to translocate animals for various reasons, or to capture injured or sick animals for treatment.¹

A variety of techniques have been used to capture deer for research and management purposes over the years. These include drop nets, drive nets, rocket nets, and live traps.² Most of these methods limit researchers’ and veterinarians’ ability to select specific animals for capture. However, chemical immobilization using a remotely delivered anesthetic agent is a selective capture technique which allows specific individuals to be targeted. This technique does not require pre-positioning of equipment such as traps or nets, which are subject to tampering by humans, and causes minimal disturbance to both wildlife and humans. Also, it does not require animals to be attracted to the capture site by bait, as is the case with preset traps.¹

Chemical Immobilization and Large Hoofstock

There is no universally ideal anesthetic for wildlife species, but the attributes of an optimal anesthetic for wildlife capture include short induction time (time to immobilization), rapid and complete reversal, and minimal physiological distress.³ Large hoofstock such as deer are often frightened and flee after being struck with a dart. Hence, long induction times allow the animal to travel a greater distance prior to immobilization. Obviously, this decreases the chance of locating the immobilized individual. Animals that are anesthetized and lost in the field face increased risk of injury or death due to physical obstacles and hazards (which would not present themselves in the case of an unimpaired animal), complications due to anesthesia or predation.

Immobilization causes certain physiological stresses in the anesthetized animal. Even with an experienced veterinarian at hand, anesthetized animals are at risk for complications such as the depression of the cardiovascular or respiratory system and disruption of thermoregulatory mechanisms. These effects may require supportive treatment by workers or initiation of anesthetic reversal prior to completion of the procedure, and may result in injury or death. The effects of many immobilization agents can be reversed with the administration of a chemical antagonist. Reversal decreases recovery times, thus reducing the risk of complications and the amount of time required to monitor and care for the immobilized animal. If the management or research protocol requires the immobilization of multiple animals, rapid recovery may allow more animals to be handled during a given period of time.¹

The MKB Formulation for Wildlife Immobilization

Numerous compounds are used to immobilize large cervids. While xylazine/telazol (XT)- and xylazine/ketamine (XK)-based agents have been used for a long time for the chemical immobilization of wildlife, more recently, medetomidine/ketamine (MK)-based formulations have gained popularity among veterinarians and wildlife managers around the globe. MK-based formulations have been used to successfully immobilize a number of cervids, including moose, sike deer, Eld’s deer, fallow deer, reindeer and mule deer.¹

Medetomidine (medetomidine hydrochloride) is a synthetic α-2-adrenoreceptor agonist with sedative and analgesic properties. Medetomidine is used by veterinarians as both a surgical anesthetic and analgesic. The pharmacological restraint and pain relief provided by medetomidine facilitates handling and aids in the conduct of diagnostic or therapeutic procedures. It also facilitates minor surgical procedures (with or without local anesthesia) and dental care where intubation is not required.

Ketamine is a fast-acting dissociative anesthetic that is often used in combination with a tranquilizer-sedative, usually a benzodiazepine or an α-2 agonist. Immobilizations with combinations including ketamine provide a rapid onset of action, immobilization within 10 min, and long duration (up to 2 hours). Ketamine provides excellent somatic analgesia, but poor visceral analgesia, and therefore it should not be used as the sole analgesic for procedures expected to cause visceral pain. When used alone, side effects include increased muscle tone, hyperthermia, excessive salivation, catecholamine release, and convulsions. Ketamine has no known antagonist; for this reason the use of a reversible drug in combination with ketamine for field immobilizations is commonly recommended.⁵

Butorphanol is also used in both dogs and cats as an adjunctive preanesthetic medication and analgesic and as an antiemetic before cisplatin treatment (although it is not very effective in cats for this indication). Compared with other opiate analgesics, butorphanol is not very useful in small animals (particularly dogs) for treating pain and has to be dosed frequently. Butorphanol can be a useful reversal agent for the CNS and respiratory depressant effects of mu-opioid agonists (eg, morphine, hydromorphone). Because of its kappa effects, butorphanol can reverse CNS and respiratory depression caused by mu-opioid agonists without completely reversing the analgesic effects.

Butorphanol has also been used in cattle, camelids, small ruminants, small mammals, and several wildlife species. Butorphanol use in reptiles is somewhat controversial, but most studies show it has minimal analgesic or anesthetic-sparing efficacy in many of these species.⁶

MKB & MKB Kit: Concentrations and Reversals

The MKB formulation by NexGen Pharmaceuticals is a premixed formulation developed to provide veterinarians and wildlife handlers with a field-tested immobilization anesthesia option that can be effectively used to immobilize a broad range of exotic animal species. Providing a faster reversal than other MK formulations, the MKB is a superior formulation for routine doctoring and general procedures. MKB consists of medetomidine (10mg/ml), which provides superior pain relief and muscle relaxation to other compounds employing α-2 adrenergic agonists, ketamine HCL (50 mg/ml), which supplies an effective paralytic and Butorphanol (30 mg/ml) for added analgesic effect. In combination, these three agents provide the three provide a safe, gentler induction and excellent recovery results.

MKB DOSING SUGGESTIONS

For any additional questions regarding NexGen’s MKB Kits, please feel free to reach out to the company. Questions concerning your specific herd should be directed to your veterinary practitioner. The above dosing information is intended for use by veterinary professionals only and is made available on the express condition that no liability, expressed or implied, is accepted by NexGen Pharmaceuticals, LLC for the accuracy, content, or use thereof. The information is to be used at the reader’s discretion. Veterinary practitioners should rely on their own expertise, knowledge and judgment when determining the appropriate dosage for MKB administration in a specific species.

For those new to utilizing NexGen’s MK formulations to manage wildlife and exotics, it is important to understand the level of anesthesia provided with medetomidine/ketamine sedation. It is a deep sedation, not to be confused with other sedations that are moderate. For NexGen’s MKB formulation, reversal agents are required in the form of Atipamezole (20 mg/ml) and Naltrexone (25 mg/ml). The MKB Kit includes the MKB formulation with accompanying reversal agents (and a manufacturer discount for purchasing the two in combination).

¹Schwertner, T., et. al. Immobilizing Captive White-tailed Deer Using Medetomidine-Ketamine versus Xylazine-Telazol. Proc. Annu. Conf. Southeast. Fish and Wildl. Agencies 56:343–35.

²Schemnitz, S. 1994. Capturing and handling wild animals. Pages 125–139 in T.A. Bookhout, ed. Research and management techniques for wildlife and habitats. The Wildlife. Society., Bethesda, Md. 740pp.

³Kreeger, T.J. 1996. Handbook of wildlife chemical immobilization. Internatl. Wildl. Vet. Serv., Laramie, Wyo. 340pp.

⁵Chinnadurai, Sathya & Strahl-Heldreth, Danielle & Fiorello, Christine & Harms, Craig. (2016). Best-practice guidelines for field-based surgery and anesthesia of free-ranging wildlife. I. Anesthesia and analgesia. Journal of wildlife diseases. 52. S14-S27. 10.7589/52.2S.S14.

⁶Fiorello, C., et. al. Best-Practice Guidelines For Field-Based Surgery Andanesthesia On Free-Ranging Wildlife. Ii. Surgery. Journal of Wildlife Diseases, 52(2) Supplement 2016, pp. S28–S39.

About NexGen Pharmaceuticals

NexGen Pharmaceuticals is an industry-leading veterinary compounding pharmacy, offering sterile and non-sterile compounding services nationwide. Unlike other veterinary compounding pharmacies, NexGen focuses on drugs that are difficult to find or are no longer available due to manufacturer discontinuance or have yet to be offered commercially for veterinary applications, but which still serve a critical need for our customers. We also specialize in wildlife pharmaceuticals, including sedatives and their antagonists, offering many unique options to serve a wide array of zoo animal and wildlife immobilization and anesthesia requirements.

Our pharmacists are also encouraged to develop strong working relationships with our veterinarians in order to better care for veterinary patients. Such relationships foster an ever-increasing knowledge base upon which pharmacists and veterinarians can draw, making both significantly more effective in their professional roles.

Disclaimer

The information contained in this blog post is general in nature and is intended for use as an informational aid. It does not cover all possible uses, actions, precautions, side effects, or interactions of the medications shown, nor is the information intended as medical advice or diagnosis for individual health problems or for making an evaluation as to the risks and benefits of using a particular medication. You should consult your veterinarian about diagnosis and treatment of any health problems. Information and statements have not been evaluated by the Food and Drug Administration ("FDA"), nor has the FDA approved the medications to diagnose, cure or prevent disease. Medications compounded by NexGen Pharmaceuticals are prepared at the direction of a veterinarian. NexGen Pharmaceuticals compounded veterinary preparations are not intended for use in food and food-producing animals.

NexGen Pharmaceuticals, LLC does not recommend, endorse or make any representation about the efficacy, appropriateness or suitability of any specific dosing, products, procedures, treatments, services, opinions, veterinary care providers or other information that may be contained in this blog post. NEXGEN PHARMACEUTICALS, LLC IS NOT RESPONSIBLE NOR LIABLE FOR ANY ADVICE, COURSE OF TREATMENT, DIAGNOSIS OR ANY OTHER INFORMATION, SERVICES OR PRODUCTS THAT YOU OBTAIN THROUGH THIS BLOG POST.