Botox AEs

Page 1

Am J Clin Dermatol 2005; 6 (3): 141-150 1175-0561/05/0003-0141/$34.95/0

LEADING ARTICLE

© 2005 Adis Data Information BV. All rights reserved.

Managing Adverse Events Associated with Botulinum Toxin Type A A Focus on Cosmetic Procedures Uwe Wollina and Helga Konrad Department of Dermatology, Hospital Dresden-Friedrichstadt, Academic Teaching Hospital, Dresden, Germany

Abstract

Botulinum toxin A (BTXA) has become a widely used drug in cosmetic dermatology, not only to treat focal hyperhidrosis but also hyperkinetic facial lines, platysma bands, d´ecollet´e bands, and other skin features. The spectrum of possible adverse effects of BTXA is broad but fortunately those that have been observed with cosmetic use of this product are generally mild and transient. The major tools for preventing adverse effects from BTXA are knowledge and skill. Use of correct injection techniques is mandatory since most unwanted effects are caused by incorrect technique. Knowledge of the target structures, e.g. the facial and extrafacial muscles, allows physicians to select the optimal dose, time and technique. The most common adverse effects are pain and hematoma. In the periocular region, lid and brow ptosis are important adverse effects. Adverse effects such as pain, hematoma, ecchymosis, and bruising may also occur in the upper and lower face and at extrafacial sites. Other possible adverse effects seen in other indications that the user of BTXA in cosmetic dermatology should be wary of include induction headaches and possible interaction with concomitant medications. Induction of neutralizing antibodies due to cosmetic BTXA treatment has not been observed. This article also outlines recommendations regarding use of BTXA. Of these, the most important for avoiding most unwanted adverse effects are the proper techniques of dilution, storage, and injection, as well as the careful exclusion of patients with any contraindications. Pain, hematoma, ecchymosis, and bruising can be prevented by cooling the skin before and after BTXA injection. Upper lid ptosis may be partly corrected using apraclonidine or phenylephrine eyedrops. If simple rules relating to the indications for and application of BTXA are followed, this is a safe and effective drug in cosmetic dermatology.

Botulinum toxin (BTX) is produced by Clostridium botulinum. This was discovered in 1905 by Tchitchikine, who described the substance as a neurotoxin.[1] BTX was purified by Sommer in California in 1920, and 36 years later Lamanna succeeded in further purifying BTX into crystalline form.[2] In 1949, it was demonstrated that BTX inhibits the release of acetylcholine from nerve endings.[3]

cle transport protein. In this way, it impedes proper binding of acetylcholine vesicles to, and fusion with, the cell membrane. Neurotransmitter release to the muscle endplate is inhibited and muscle contraction prevented. The deadly dose for humans has been estimated to be 3000U of Botox® 1.[3,4]

BTX consists of two different chains, a heavy chain that is responsible for binding to the nerve ending and a light, toxifying chain. Following endocytosis, the molecule is cleaved by disruption of a disulfide bond. Seven different types of BTX are known, but only BTXA and very recently BTXB have been approved as drugs for human use. The target for BTXA is a 25kDa synaptosome-associated protein. The binding is rapid and stable. BTXA, a zinc-dependent endopeptidase, cleaves the 25kDa vesi-

There are two different BTXA products on the international market – Botox® (Allergan) and Dysport® (Speywood/Ipsen). The two formulations have different biological potencies.[4] However, the exact relative potencies of the two products are still a matter of debate. While the potency of both BTXA products is expressed in LD50 mouse units (the amount of toxin required to kill 50% of test mice), the assays used for each are different. However, one vial of Botox® contains 100U, whereas one vial of Dysport® contains

1

1. Botulinum Toxin A Brands

The use of trade names is for product identification purposes only and does not imply endorsement.


Turn static files into dynamic content formats.

Create a flipbook
Issuu converts static files into: digital portfolios, online yearbooks, online catalogs, digital photo albums and more. Sign up and create your flipbook.