What is the recommended use and dosage of medetomidine in veterinary settings?

From the Guidelines

Medetomidine is recommended for use in veterinary settings as part of a combination anesthesia, specifically with ketamine and atropine, to preserve stable blood pressure in different genetic mouse strains. The recommended dose is not explicitly stated for medetomidine alone, but as part of a combination, the final doses of ketamine, xylazine, and atropine are 100,20, and 0.6 mg kg−1, respectively 1. Medetomidine has a high selectivity for alpha–2 receptors 1, which makes it a suitable choice for sedation and anesthesia in veterinary medicine.

When considering the use of medetomidine, it is essential to note that the choice of anesthetic combination depends on the specific requirements of the animal and the procedure being performed. Other options, such as pentobarbital or isoflurane, may be more suitable in certain situations 1. However, the combination of ketamine, medetomidine, and atropine is considered one of the best anesthetic combinations for preserving stable blood pressure in different genetic mouse strains 1.

Key considerations when using medetomidine include:

• Monitoring for cardiovascular effects such as bradycardia and hypotension
• Careful calculation of dosages based on species-specific requirements
• Use of atipamezole for reversal of medetomidine effects
• Cautious use in geriatric animals or those with cardiovascular, respiratory, hepatic, or renal disease
• Maintenance of patient warmth during recovery 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION: The dose is based on body surface area (BSA). Calculate the dose using 1 mg medetomidine /m2 BSA or use the dosing table below. Note that the mg/kg dosage decreases as body weight increases. Table 1. IM dose volume based on body weight Dog body weightDose volume lbskgmL 4.4 to 72 to 30.3 7.1 to 93.1 to 40.4 9.1 to 114.1 to 50.6 11.1 to 225.1 to 100.8 22.1 to 2910. 1 to 131.0 29.1 to 3313.1 to 151.2 33.1 to 4415.1 to 201.4 44.1 to 5520.1 to 251.6 55.1 to 6625.1 to 301.8 66.1 to 7330.1 to 332.0 73.1 to 8133.1 to 372.2 81.1 to 9937.1 to 452.4 99.1 to 11045.1 to 502.6 110.1 to 12150.1 to 552.8 121.1 to 13255.1 to 603.0 132.1 to 14360.1 to 653.2 143.1 to 15465.1 to 703.4 154.1 to 17670.1 to 803.6

176>803. 8

The recommended use and dosage of medetomidine in veterinary settings is based on body surface area (BSA), with a dose of 1 mg medetomidine /m2 BSA. Alternatively, a dosing table is provided to determine the IM dose volume based on body weight. The dose should be administered via IM injection, and the dog should be allowed to rest quietly until evidence of sedation has occurred (5-15 minutes) 2.

• Key points:
  • Calculate the dose using 1 mg medetomidine /m2 BSA
  • Use the dosing table to determine IM dose volume based on body weight
  • Administer the dose via IM injection
  • Allow the dog to rest quietly until sedation occurs (5-15 minutes)
• Reversal of sedation: Administration of IM atipamezole hydrochloride at the approved dose can reverse the sedative and cardiovascular effects of medetomidine within 5-10 minutes 2.

From the Research

Recommended Use and Dosage of Medetomidine

The recommended use and dosage of medetomidine in veterinary settings vary depending on the species and the intended procedure.

• For dogs, the mean dose of medetomidine used for examinations, clinical procedures, and minor surgical interventions is 40 micrograms/kg, and for radiography, it is 30 micrograms/kg 3.
• In cats, the dose is 80-110 micrograms/kg 3.
• Medetomidine can be used as a preanesthetic prior to ketamine, barbiturate, and halothane anesthesia 4.
• The concomitant use of medetomidine (80-100 micrograms/kg) and ketamine (7 mg/kg) in cats provides a good anesthesia (20-40 min) with smooth recovery 3.

Physiological Effects and Side Effects

Medetomidine has several physiological effects, including:

• Dose-dependent sedation and analgesia 5, 4
• Bradycardia, which can be transiently prevented with atropine or glycopyrrolate medication 4
• Initial increase in arterial blood pressure followed by a longer-lasting slightly hypotensive or normotensive period 4
• Decreased respiratory frequency, which stays within normal limits for resting animals 4
• Vomiting, which may occur during the induction period of sedation 3, 4
• Occasional muscle jerks 3, 4
• Hypothermia, which has been reported in every animal sedated with medetomidine 4

Reversal of Medetomidine-Induced Effects

Atipamezole is a highly effective and safe agent in reversing medetomidine-induced sedation-analgesia, recumbency, and bradycardia in dogs 6.

• Atipamezole at dose rates of 80-240 micrograms/kg rapidly and effectively reverses medetomidine-induced deep sedation-analgesia, recumbency, and bradycardia 6.
• The median arousal time after atipamezole is 3-5 min, and walking time is 6-10 min compared to greater than 30 min for both effects after placebo 6.