Why would insufflation or inhalation of a single vial of powdered onabotulinumtoxinA (Botox®) be unlikely to cause systemic botulism?
OnabotulinumtoxinA is supplied in 50 and 100 unit vials. There is 0.73 ng of botulinum toxin A per 100 units of onabotulinumtoxinA. It is estimated that lethal amounts of crystalline type A toxin for a 70kg human would be approximately 0.7 to 0.9 mcg inhalationally. Therefore, a single insufflated 100 unit vial of onabotulinumtoxinA would contain approximately 0.3% of the estimated lethal inhalational dose.
Arnon SS, Schechter R, Inglesby TV, Henderson DA, Bartlett JG, Ascher MS, Eitzen E, Fine AD, Hauer J, Layton M, Lillibridge S, Osterholm MT, O’Toole T, Parker G, Perl TM, Russell PK, Swerdlow DL, Tonat K; Working Group on Civilian Biodefense. Botulinum toxin as a biological weapon: medical and public health management. JAMA. 2001 Feb 28;285(8):1059-70. doi: 10.1001/jama.285.8.1059. Erratum in: JAMA 2001 Apr 25;285(16):2081. PMID: 11209178.
Contributed by: Catherine Dong, MD