Combining Fillers and Neuromodulators in the Same Syringe

September 2013 | Volume 12 | Issue 9 | Editorials | 976 | Copyright © September 2013

Joel L. Cohen MD and Kavita Mariwall MD

Denver, CO and New York, NY

In reviewing literature on combination techniques for facial rejuvenation, we came across Dr. Kenner’s September 2010 article entitled “Hyaluronic Acid Filler and Botulinum Neurotoxin Delivered Simultaneously in the Same Syringe for Effective and Convenient Combination Aesthetic Rejuvenation Therapy.” The article elaborates Dr. Kenner’s technique of mixing HA filler, lidocaine, epinephrine, and neuromodulator using a syringe and female-to-female connector with “10 back and forth mixings to ensure even distribution.” We were surprised that there has not been editorial response to this paper as it presents several concerns.
Dr. Kenner’s non-standardized mixing does not allow the practitioner to know exactly how many units of neuromodulator are being injected into an area. While the precise number of units can be debated for a given muscle group, there are standard ranges that most practitioners can agree upon for the glabellar complex and the crow’s feet (the areas treated in this paper) that have been published in various consensus recommendations for each of the three FDA-approved available neuromodulators. The mixing carries with it the potential for not only under-dosing an area but also more importantly the technique risks spread of neuromodulator to adjacent unintended musculature. The concern for unanticipated and unwanted spread of the mixed contents to adjacent tissue is especially high given the recommendation in her article for massage after injection. For example, if the lateral canthal area is injected, there is no control over spread of toxin to the undesired zygomaticus minor muscle. The technique thus increases the risk of unwanted side effects and can even end up increasing the cost for the practitioner who may need to perform touch ups for the patient if a muscle area is inadequately treated. In addition, there is no literature to support that mixing the two products together in the same syringe is safe and does not alter the property of one of the solutions, nor has it been proven that 10 back and forth mixings does in fact ensure even distribution. For practitioners using Radiesse, often times despite several back and forth mixings pockets of unevenly mixed product aliquots still occur quite commonly in our experience.
In the article, Dr. Kenner uses filler mixed with lidocaine and epinephrine in the glabellar region, which carries with it the obvious concern for vascular compromise leading to glabellar necrosis and supplanting that, a potential for arterial injection of an unknown quantity of toxin. The author reports that the advantage of mixing the lidocaine and epinephrine with the filler and neurotoxin is that the area will then be “still” for a few hours to allow for the filler to be massaged into the area smoothly. In our experience using pre-mixed HA fillers with lidocaine, patients continue to have full movement of the areas immediately after injection thus negating this type of advantage.
While we appreciate Dr. Kenner’s photographs, we felt it important to raise a flag for the record cautioning practitioners about the potential pitfalls of using such “mixing” techniques when performing combination aesthetic treatments. Same day treatments are one thing, but the “kitchen sink approach” to everything in one unstandardized syringe on that day is yet another—and is very concerning to us. In the future, controversial articles, such as this one, should be accompanied by a commentary that serves to indicate these types of concerns without delay.


Dr. Cohen has served as a consultant for Allergan, Medicis (Valeant), Merz, and Galderma.


  1. Kenner JR. Hyaluronic Acid Filler and Botulinum Neurotoxin Delivered Simultaneously in the Same Syringe for Effective and Convenient Combination Aesthetic Rejuvenation Therapy. J Drugs and Dermatol. 2010; 9(9):1135-1138.