Summary
Health Canada approved the use of Botox to treat neurogenic
bladder (Neurogenic Detrusor Overactivity) associated with MS and
spinal cord injury. Botox is a powerful neurotoxin that
temporarily blocks connections between the nerves and muscles,
resulting in short-term relaxation of the targeted muscle.
Injections have been shown in clinical trials to relieve
spasticity in individual muscles for three to nine months.
Botox was approved in June 2012 by the by the Common Drug Review (CDR) of the Canadian Agency on Drugs and Technologies in Health (CADTH). Read more
Details
Two double-blind, placebo-controlled, randomized, multi-centre
phase III clinical studies involving 691 participants with MS or
spinal cord injury with urinary incontinence were randomized to
receive either 200 Units of Botox ®, 300 Units of
Botox®, or placebo. Significant improvements compared
to placebo were observed for Botox® in both
studies.
Injection of the bladder muscle with Botox is performed using
cystoscopy, a procedure that allows a physician to visualize the
interior of the bladder. Cystoscopy may require general
anesthesia. According to the Health Canada label, Botox is
approved as a 200U dose for people with urinary incontinence due
to detrusor (the primary bladder muscle) overactivity associated
with a neurologic condition. People are to be considered for
retreatment when the clinical effect of the previous treatment
wears off but no sooner than 3 months from the prior bladder
injection. The safety and efficacy data beyond two treatments are
limited.
The most common adverse events included urinary tract infection
and urinary retention. The medication carries a boxed warning
that Botox injections may cause serious side effects that can be
life threatening. These include problems swallowing, speaking or
breathing, and the possibility that the toxin may spread to other
areas of the body away from the injection site.
The next step following Health Canada approval is for Botox to be
reviewed by the Common Drug Review (CDR) of the Canadian Agency
on Drugs and Technologies in Health (CADTH). The MS Society of
Canada has provided input from the viewpoint of potential users
to the Common Drug Review (CDR) for its review of Botox. CDR is a
pan-Canadian process for reviewing clinical, cost-effectiveness
and patient evidence for drugs. It also provides formulary
listing recommendations to Canada’s publicly funded drug plans
(except Quebec).
Botox is a registered trademark of Allergan, Inc.
With information from Health Canada and the National MS Society
(USA).