MKBM™ Kit (Sedation & Reversal)
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- Product Type:
- Controlled Substance:
- Schedule CIII
Anesthesia plays a critical role in wildlife veterinary medicine. Relocation and other management procedures, preventive medicine, imaging and surgery are among the key interventions typically carried out on wildlife species and which nearly always require chemical immobilization. Wildlife practice is a highly-specialized area of veterinary medicine, and this is particularly true in the area of chemically immobilizing large and exotic hoofstock.
The modern chemical immobilization techniques which exist today were originally pioneered beginning in the late 1950s by wildlife managers in South Africa. A great many species encountered during the period from the late 1950s through the late 1970s underscored the vast differences between chemical immobilization requirements across large exotic species.
As procedures involved in chemical immobilization developed, veterinarians and wildlife managers sought the optimal drug combinations to effectively anesthetize wildlife species. This period involved a great deal of trial-and-error. While some drugs worked well on certain species, they often did not work well on other or even closely-related species. Some drugs worked very well, but had unforgiving safety margins which could easily lead to the death of an animal.
In recent years, and especially given concerns in the area of conservation and humane treatment, great care has been taken with chemical immobilization protocols and drug development to keep these within safety margins through the use of novel anesthetics, including combinations of true anesthetics, neuromuscular blockers and tranquilizers.2 Thus, modern chemical immobilization techniques have dramatically reduced the side-effects of drugs and mortalities. Additionally, the use of antagonists to anesthetics is now widely employed, as this avoids the undesirable and potentially harmful effects of drugs and facilitates speedy recovery from chemical immobilization events.1,2
Reversal agents (antagonists) are drugs that are used to reverse the effects of anesthetics and narcotics. The drugs and drug dosages for the chemical immobilization of wildlife are highly variable, and factors such as concurrent medications, medical conditions, species, age, sex and other factors contribute to this variability. Consequently, the development of reversal agents and the refinement of their applications are ongoing.
The MKBM™ Kit for Exotic Wildlife Species
The MKBM™ Kit is an original formulation by NexGen Pharmaceuticals, containing
Medetomidine hcl 20 mg/ml
Ketamine hcl 100 mg/ml
Butorphanol 30 mg/ml
The MKBM™ Kit also includes the reversal agents
Naltrexone 50 mg/ml
The MKBM™ Kit is indicated for the chemical immobilization of numerous large exotic hoofstock species. It is an excellent choice for anesthetizing bongo, kudu, gazelle, eland, as well as other African hoofstock and certain domestic wildlife species.
Medetomidine (medetomidine hydrochloride) is an α-2-adrenoreceptor agonist with sedative and analgesic properties. It is used by veterinarians as both a surgical anesthetic and analgesic. Its pharmacological restraint and pain relief properties facilitate handling and aid in diagnostic and therapeutic procedures. Used alone and in combination with other drugs, medetomidine has been shown to be useful for anesthesia and immobilization in zoo animals and exotic species.3
The pharmacologic effects of medetomidine include: depression of CNS (sedation, anxiolysis), GI (decreased secretions, varying effects on intestinal muscle tone) and endocrine functions, peripheral and cardiac vasoconstriction, bradycardia, respiratory depression, diuresis, hypothermia, analgesia (somatic and visceral), muscle relaxation (but not enough for intubation), and blanched or cyanotic mucous membranes. Medetomidine also induces sedation for a longer period than does xylazine, and its sedative effects persist longer than its analgesic effects.3
Ketamine is a dissociative general anesthetic and an NMDA-receptor antagonist that has been used in many species in veterinary medicine. Ketamine is used to induce general anesthesia and as a constant rate infusion to provide analgesia and decrease the amount of inhalant used to maintain a surgical plane of anesthesia.3
Ketamine has significant analgesic activity and a relative lack of cardiopulmonary depressant effects. It induces both anesthesia and amnesia by functionally disrupting the CNS through over-stimulating the CNS or inducing a cataleptic state. Ketamine also interacts with opioid and monoaminergic receptors, which contributes to the antinociceptive effects of this drug.2,3
Butorphanol (butorphanol tartrate) is a synthetically derived opioid agonist-antagonist analgesic of the phenanthrene series, with a potency of about four to seven times that of morphine. In the United States, it is a U.S. Drug Enforcement Administration (DEA) class IV controlled substance. Butorphanol is a mixed agonist-antagonist with low intrinsic antagonist activity at receptors of the mu1 (µ1) and mu2 (µ2) opioid type (morphine-like), which are responsible for the significant opioid side effects and also an agonist with a high affinity for kappa (κ) opioid receptors.3
General anesthesia poses increased risks for larger exotic species, such as cardiorespiratory depression, myopathy, and hyperthermia. In ruminants, ruminal bloat and regurgitation of rumen contents with potential aspiration pneumonia are added risks. Thus, the use of heavy sedation such as is provided by butorphanol is justified for these species.4
Midazolam is a benzodiazepine that is usually used as a preoperative medication. In veterinary patients, midazolam is used for its sedative, anxiolytic, and muscle relaxant properties prior to induction of general anesthesia. When midazolam is used alone, sedation may be adequate in ruminants, camelids and several other species. When used in combination with other drugs (e.g., opioids, ketamine, acepromazine, dexmedetomidine), midazolam provides more reliable sedation.3
Midazolam exhibits similar pharmacologic actions as other benzodiazepines, depressing subcortical levels of the CNS, which produces anxiolytic, sedative, skeletal muscle relaxant, and anticonvulsant effects. Midazolam has unique solubility characteristics that provide a rapid onset of action after injection. Compared to diazepam, midazolam has ≈2 times the affinity for benzodiazepine receptors, is nearly 3 times as potent, and has a faster onset of action and a shorter duration of effect.3
Atipamezole is a common reversal agent for α2-adrenergic agonists such as dexmedetomidine, medetomidine and xylazine.3 It competitively inhibits α2-adrenergic receptors, reduces sedation, decreases blood pressure, increases heart and respiratory rates, and also reduces the analgesic effects of α2-adrenergic agonists. Peak plasma concentration of atipamezole occurs within ≈10 minutes after IM administration. It is metabolized in the liver to compounds that are eliminated in the urine.3
Because reversal with atipamezole can occur rapidly, it is advised that caution is exercised, since animals emerging from sedation and analgesia may exhibit unexpected or aggressive behaviors. Additional analgesia with a non- α2-adrenergic agonist (e.g., opioids) may be considered, especially after painful procedures.
Naltrexone is an opiate antagonist. It competitively binds to opiate receptors in the CNS, thereby preventing both endogenous opioids and exogenously administered opioid agonists or agonist/antagonists from occupying the site. Naltrexone may be more effective in blocking the euphoric aspects of the opioids and less effective at blocking the respiratory depressive or miotic effects.3
Due to its long duration of action (approximately twice that of naloxone), naltrexone is preferred in wildlife and zoo animals when potent opioids are used.3 The more potent available opioids are long-acting, thus the use of naltrexone minimizes the potential of re-narcotization, especially when re-dosing of antagonists is not possible due to concerns for the safety of personnel.
Where to buy the MKBM™ Kit
The MKBM™ Kit is an original formulation available exclusively through NexGen Pharmaceuticals. It is indicated for the chemical immobilization of large exotic hoofstock and other exotic species.
The MKBM™ formulation carries numerous potential drug interactions. Please consult your veterinarian prior to beginning any treatment regimen.
FOR RX ONLY: A valid prescription from a licensed veterinarian is required for dispensing this medication.
1Arnemo, Jon & Kreeger, Terry. (2018). Handbook of Wildlife Chemical Immobilization 5th Ed. Sunquest Publishing, 2007, 432 pages.
2Nielsen, L. Chemical Immobilization of Wild and Exotic Animals. (1999) Ames, Iowa, Iowa State University Press.
3Plumb’s Veterinary Drugs.
4Bouts T., et. al. Detomidine and Butorphanol for Standing Sedation in a Range Of Zoo-Kept Ungulate Species. J Zoo Wildlife Medicine. 2017 Sep; 48 (3):616-626.