• ZooPharm
  • ZooPharm
  • ZooPharm
  • ZooPharm
Tolazoline HCI 30ml - 200mg/ml

Tolazoline HCI 30ml - 200mg/ml

Category: WILDLIFE

Tolazoline hydrochloride is a combination alpha-one and alpha-two antagonist developed to reverse the sedation and analgesia effects of xylazine hydrochloride. Tolazoline hydrochloride was developed and marketed for use in horses by Lloyd Laboratories in the 1990s. It was approved under the trade name Tolazine in 1996. Prior to this tolazoline was available as the human formulation trademarked Priscoline at a concentration of 25 mg/ml from Novartis.

Indications: Wildlife Management


In field applications, as a general rule, tolazoline is more effective in antagonism of an alpha-two agonist in the non-domestic members of the family Bovidae. It appears to be equal to yohimbine in Cervidae although veterinarians in the field have reported seizures in some of Asian species of deer when tolazoline was used to reverse xylazine (Bush, R. 1999. Personal communication). Some of the key literature regarding tolazoline use in non-domestic species is as follows:

  1. White-tailed deer (Kreeger et al. 1986. J Wildl Dis 22:407-412 re: efficacy of
tolazoline to reverse xylazine HCl)
  2. Elephant (Raath, J.P. 1993. In Capture and Care Manual, pp. 484-511)
(Kock et al. 1993. In Zoo and Wildlife Medicine Current Therapy 3,
pp. 436-441)
  3. Bighorn sheep and other ruminants. Kreeger (Handbook of Wildlife Chemical Immobilization, 200l) states that tolazoline appears to provide a “more consistent”
 antagonism than yohimbine in reversing xylazine sedation.(Allen, J. L. 1989.
Proc. AAZV, pp. 3-4)
  4. Non-domestic bovids (Klein, L. and Klide, A. 1989. J Zoo Wildl Med 20:138-153
re: bovids appearing to respond “more reliably” to tolazoline than yohimbine)

Indications: Domestic Sepcies

Tolazoline HCl is used in horses to reverse the effects of sedation and analgesia from
xylazine HCl. Studies conducted by Lloyd Laboratories have demonstrated efficacy
of tolazoline in reversing xylazine sedation in cattle. (Powell et al. 1998. JAVMA
212(1):90-92)

Chemistry

Tolazoline hydrochloride belongs to the synthetic group of alpha-adrenergic blocking
agents known as imidazole derivatives. It is a mixed alpha-1 and alpha-2 adrenergic
receptor antagonist that competitively inhibits alpha-adrenoreceptors. Tolazoline is
also a direct peripheral vasodilator that decreases peripheral resistance and increases venous capacitance. (Tranquilli et al. 1984. JAVMA 184:1400-1402)

Chemically, tolazoline hydrochloride is 1H-imidazole,4,5-dihydro-2-(phenylmethyl)-
monohydrochlroide.

Pharmaconetics

Tolazoline hydrochloride belongs to the synthetic group of alpha-adrenergic blocking agents known as imidazole derivatives. It is a mixed alpha-1 and alpha-2 adrenergic
receptor antagonist that competitively inhibits alpha-adrenoreceptors. Tolazoline is
also a direct peripheral vasodilator that decreases peripheral resistance and increases venous capacitance. (Tranquilli et al. 1984. JAVMA 184:1400-1402)

Dosage

The tolazoline hydrochloride dose is 4.0 mg/kg body weight or 1.8 mg/lb. (4ml/100kg or 4ml/220 lb.) to reverse the sedative effects of xylazine hydrochloride in horses.

In studies with cervids, a dose of 2mg/kg of tolazoline to reverse xylazine in deer, 
resulted in a reduced time to standing.
Tolazoline hydrochloride should be administered slowly by intravenous injection at a rate of approximately 1 ml per second. Onset of arousal is usually apparent within 5 minutes of tolazoline hydrochloride administration, depending on depth and duration of xylazine-induced sedation.

How supplied

Tolazoline hydrochloride was approved by FDA in 1996 in a 100mg/ml concentration.
Tolazoline hydrochloride is routinely compounded and available from ZooPharm in a 200mg/ml concentration in 30 ml multiple use vials.

Contraindications

Heart rate may briefly increase immediately after tolazoline Hall injection at the recommended dose with a return to pre-treatment rate within 5-10 minutes. In safety studies, the degree and duration of tachycardia increased with higher doses, although the increased rate usually lasted less than 60 minutes.

WARNING:
Tolazoline hydrochloride is not for use in food-producing animals.


Caution
Tolazoline hydrochloride should not be administered to animals exhibiting signs of
stress, debilitation, cardiac disease, sympathetic blockage, hypovolemia or shock.

ADVERSE REACTION
When administered without prior xylazine administration in horses, tolazoline hydrochloride caused gastrointestinal hypermotility. Some horses exhibited mild colic and transient diarrhea.

 

 

 

AddThis Social Bookmark Button