1) A double-blind study is one in which neither
the participants nor the experimenters know who is receiving a
particular treatment. This procedure is utilized to prevent bias in
research results. Double-blind studies are particularly useful for
preventing bias due to demand characteristics or the placebo
effect.
Controlled study is an experiment or clinical
trial in which two groups are used for comparison purpose. In a
controlled exposure study, one group of participants is exposed to
a substance (e.g.a drug or a pollutant) while those in the
"control" group are not.
2) Normally, your nerves send electrical messages to your
muscles so they will move when you want them to. These messages
travel from the nerves to the muscles via a chemical called
acetylcholine. But if you have MS, the disease damages the nerves
and throws those signals out of sync. It makes your muscles tense
up and move when you don’t want them to.
- Botulinum toxin type A works by blocking the release of
acetylcholine from nerve endings. Acetylcholine is a
neurotransmitter required by muscles for muscular contraction. By
eliminating the ability of a muscle to contract, it relaxes,
thereby decreasing spasticity and tone.
- The blockade of acetylcholine does not occur immediately. Most
patients do not begin to see the effect of a botulinum toxin
injection for a few days, and it may take a few weeks for the
maximum benefit to become apparent.
- Additionally, the benefit of botulinum toxin injections is not
permanent; after a few months (typically three), the effect of the
injections is no longer seen, and the injections need to be
repeated.
3) Local weakness of the injected muscle represents the expected
pharmacological action of botulinum toxin. However, weakness of
nearby muscles may also occur due to spread of toxin.Long term
inhibition of acetylcholine release at the neuromuscular junction
of striated muscles, thus resulting in chemical denervation and
muscle weakness or paralysis.
4) Other uses:
- Treatment of urinary incontinence due to
detrusor overactivity associated with a neurologic condition [e.g.,
spinal cord injury (SCI), multiple sclerosis (MS)] in adults who
have an inadequate response to or are intolerant of an
anticholinergic medication.
- Prophylaxis of headaches in adult patients with chronic
migraine (≥15 days per month with headache lasting 4 hours
a day or longer).
- Treatment of upper limb spasticity in adult
patients.
- Treatment of cervical dystonia in adult
patients, to reduce the severity of abnormal head position and neck
pain.
- Treatment of severe axillary hyperhidrosis
that is inadequately managed by topical agents in adult
patients.
- Treatment of blepharospasm associated with
dystonia in patients ≥12 years of age.
- Treatment of strabismus in patients ≥12 years
of age