All BTX-A work the same way and are basically interchangeable.
A new BTX-A with a stabilizing peptide called RTP004 from Revance has joined the market.
BTX-A tends to “prejuvenate” the skin and prevent aging when used consistently.
More research is necessary to determine how to titrate diffusion and how much diffusion is preferred for cosmetic indications.
More studies are needed to determine the safety of intradermal BTX-A to treat fine lines.
Preliminary data suggest BTX-A has an anti-aging effect separate from its ability to immobilize muscles. More data are needed to understand the “prejuvenation” abilities of BTX-A.
Shorter acting toxins are coming.
Studies evaluating the use of BTX-A to treat rosacea and acne as well as to reduce oil secretion are on the horizon.
Botulinum toxin (BTX), an exotoxin produced by the bacteria Clostridium botulinum, occurs in nature. BTX induces a bilaterally symmetric descending neuroparalytic condition called botulism. The word “botulinum” is derived from the Latin word for sausage, botulus. Botulism was so named during the Napoleonic era in the early 1800s when it was noted to be triggered by the ingestion of spoiled sausages. Later, German physician Justinus Kerner described food-borne botulism and its clinical symptoms during the period between 1817 and 1822. In 1946, Schantz reported isolating BTX type A in its crystalline form, and nearly a quarter of a century later, Alan Scott became the first to harness the effects of BTX for medicinal use in monkey strabismus.1
The use of C. botulinum A exotoxin, commonly known as botulinum toxin type A (BTX-A), has emerged over the last 20 years as one of the most popular methods of combating cutaneous signs of aging, particularly the dynamic wrinkles of the face. The therapeutic application of this potent neurotoxin has carved a comfortable niche in the cosmetic realm of dermatology practice for practical reasons: Results appear within several days of administration, the procedure itself is short in duration and relatively uncomplicated, and side effects are minimal.
Although medicinal use of BTX by physicians is widespread, professional opinions vary as to the best ways to administer the treatment. For instance, the ideal dilution of the toxin, the number of units to inject, and the longevity of prepared and refrigerated BTX remain debated issues (Box 23-1). The methods described in this chapter are those used most frequently by the authors. The novice injector should try the various methods espoused by experienced specialists to determine which yields the best results in his/her own practice.
BOX 23-1 Units of Botulinum Toxin
One unit (U) of BTX is the dose that would be lethal to 50% (LD50) of the specific mouse species tested. For a 70-kg person, the LD50 of Botox is 2500 to 3000 U. However, manufacturers use different mouse models, so a unit of one brand ...