Zynrelef contains DMSO which is a sulfur compound has a slight smell but nothing offensive in terms of what a typical OR encounters. My team has not even mentioned it.
Zynrelef is not difficult to work with and only requires 1-2 minutes for application. It is a novel process and a viscous substance but surgeons have no difficulty working with the product and requires no specialized training to administer. On the contrary Exparel requires 120 injections/aspirations for proper instillation in a TKA case which can take 10-15 minutes if done properly. 5-6 cases per day is another hour of OR time lost or an additional patient lost using a product that does not work beyond the spinal or nerve block duration. (waste of $$$.) Any provider using Exparel has not read the literature. Check with the American Society of Anesthesia ( ASA ) and American Academy of Orthopedic Surgeons ( AAOS ) whom both do not recommend Exparel.
Zynrelef has had no reports of infection. Clinical trials showed no difference in infection rate between placebo, bupivacaine, or Zynrelef. Bupivacaine actually exhibits antimicrobial effects. Zynrelef has actually shown antimicrobial effects a study of Zynrelef in agar showed significant zone of inhibition against staph aureus isolates.
Exparel is losing formulary status at many institutions in favor of Zynrelef. Exparel has not beat standard of care bupivacaine, does not have an extended release profile or label, and adds no benefit in terms of pain control or opioid reduction.
Zynrelef is the first product to demonstrate superiority over standard of care bupivacaine for pain reduction and opioid reduction. AAOS recommends use of local infiltration anesthesia as part of MMA protocol. (Recommends against use of exparel.) Zynrelef was granted and extended release labeling from FDA and fills the significant efficacy gap from 12-72h that current products do not. Controlling pain in the first 72h and reducing opioid consumption decreases LOS, improves functional outcomes, and reduces risk of chronic pain/opioid use.