Abo‐, Inco‐, Ona‐, and Rima‐Botulinum Toxins in Clinical Therapy: A Primer

Abstract

Botulinum neurotoxin (BoNT) is an acetylcholine release inhibitor and a neuromuscular-blocking agent used for the treatment of a variety of medical and cosmetic indications. Currently, in the United States, there are four BoNT formulations licensed for use: abobotulinumtoxinA, incobotulinumtoxinA, onabotulinumtoxinA, and rimabotulinumtoxinB. These revised name designations were established to reinforce the understanding that each BoNT product has an individual potency and is not interchangeable with any other BoNT product. The therapeutic use of BoNTs is expanding and new formulations are on the horizon. This article is a primer that describes distinctions among currently available, licensed BoNT formulations. Toxin pharmacology, product characteristics, storage, handling, preparation, and dosages will be reviewed. In addition, issues related to dose equivalency ratios, immunogenicity, potency, and toxin spread will be discussed. Therapeutic indications and safety are discussed briefly. Knowledge of the available and licensed BoNT formulations and the ability to make distinctions in toxin pharmacology, product characteristics, and indications are vital for product selection, preparation, drug information, avoidance of drug errors, quality assurance, and patient safety.

Rationale for use of onabotulinum toxin A (BOTOX) in chronic migraine

“…Then, the light chain undergoes a conformational change and cleaves the SNAP-25, whose integrity is required for the full fusion of synaptic vesicle membrane with plasma membrane [11]. In this way, BoNT-A compromises the delivering of neurotransmitters into the synaptic cleft and the expression of protein channels or receptors on the cell surface, inducing a chemical denervation in motor, autonomic, and sensory fibers [7,11]. BoNT-A inhibits the release of glutamate, serotonin, noradrenaline, dopamine, gamma aminobutyric acid (GABA), enkephalin, glycine, substance P, ATP, and CGRP [12][13][14][15][16][17][18].…”

“…Of the seven immunologically distinct toxins (A-G), the serotype A has been used in human therapy since 1980 when Scott proposed BoNT-A injection into extraocular muscles as an alternative to strabismus surgery [6]. Nowadays, BoNT-A has therapeutic indications for cervical dystonia, blepharospasm, strabismus, upper limb spasticity, primary axillary hyperhidrosis, overactive bladder, and chronic migraine [7].…”

Global Aesthetics Consensus

“…11 This is to clarify that different formulations are chemically and pharmacologically unique, that their doses are not interchangeable, and that their dose-response curves are not parallel. 11–15 …”

In-vivo comparison of the neurotoxic potencies of incobotulinumtoxinA, onabotulinumtoxinA, and abobotulinumtoxinA

“…These BoNT/A preparations are produced by different methods and vary in the amount of total protein and complexing proteins [3][4] resulting in differences in the effect strength and, possibly, in effect duration.…”

“…The suggested conversion ratios vary between 1:1 and 1:6 [16][17][18]. The conversion ratio between A/Inco and A/Abo is usually based on the data outlined above and only interpolated [3,13,15].…”