Report Animal Concerns

Urgent Notice: Standard Xyzaline Concentration No Longer Available


Vial of 20mg/ml Xylazine with urgent warning icon

We have recently learned that the standard concentration of xylazine (20 mg/ml x 20 ml vial – Ana-Sed) used by many U-M laboratories for sedation/anesthesia is no longer available.

This specific formulation was manufactured by a supplier (Akorn Pharmaceuticals) that has recently gone out of business and, as such, the product has been discontinued. Currently, there are no other suppliers manufacturing a similar xylazine injectable product with a 20 mg/ml concentration.

Laboratories needing to order xylazine may purchase supplies from the U-M’s strategic vendor, MWI Animal Health. However, please be aware that the only xylazine formulation currently available for purchase is a 100 mg/ml concentration.

If your lab plans to stock this higher concentration, we strongly suggest adding a warning sticker (see example below) to all new vials to ensure that personnel continue to adhere to appropriate dilution and dosage requirements.

It is of critical importance to inform all personnel that this alternative source is much more concentrated than the standard source and MUST be appropriately diluted to avoid harming animals.

Yellow Caution High Concentration sticker adapted from Health Care Logistics

You may also consider switching to dexmedetomidine (dexdomitor), also available through MWI Animal Health. This drug is within the same therapeutic class, yet has a different potency, duration, and dose. As an important reminder, all drugs must be listed in your IACUC approved protocol BEFORE administration to animals.

We are aware that this manufacturer has also issued a voluntary nationwide recall of other veterinary drug products as part of their closure. We are currently evaluating the potential impacts this may have on the U-M research community and will provide additional guidance and information as soon as it becomes available.

Where to Get Help

If you are concerned about how your research may be impacted by this discontinuation:

  • Contact your ULAM Faculty Veterinarian – for guidance on selecting alternative medications and proper dilution techniques. Your ULAM Faculty Veterinarian can also provide veterinary approval for the use of any alternative drugs. If you don’t know your veterinarian, send an email to the ULAM Business Office at and your question will be routed appropriately.
  • Contact the Animal Care & Use Office ( for assistance with modifying and submitting protocol amendment(s) that may be required for a change in medication(s) and/or dosing procedures.

ULAM Faculty Veterinarians are also hosting in-person Vet Check-In Meetings throughout the end of April and early May in animal care facilities across campus. One member from each laboratory is encouraged to attend a meeting with their facility’s veterinarian to learn more about this change to xylazine availability as well as other important updates impacting the U-M research community.

We apologize for any inconvenience this may cause and are committed to helping you find solutions that will minimize potential impacts to your studies and to the animals entrusted to our care.

Last updated: