Botulinum Toxin Type A

New Information About an Old Medicine

Kevin C. Smith, MD, FRCPC (Dermatology)


Skin Therapy Letter. 2011;16(8) 

In This Article

Non-interchangeability of Products

There is no consensus on how to switch patients between the three formulations. Each formulation is dosed using units specific to the product, which are determined in a manner that is proprietary to the manufacturer. It is important to note that because the dosing units are unique to each formulation, the products are considered to be non-interchangeable.[5]

While it is possible to construct test systems in which various dose ratios can be compared under standard conditions (e.g., hyperhidrosis on the forehead[6] or frontalis muscle contractions[7]), there is no simple ratio that can be used to facilitate conversion of patients from one formulation of BoNT-A to another.[8,9]