“Botulinum Toxin in Parkinsonism”

(As this article was mentioned by Dan Brooks in tonight’s webinar, I figured I had better post it here!)

This article on the use of Botox in parkinsonism (PD and atypical parkinsonism) is in the Spring ’09 issue of the APDA (American Parkinson Disease Association) quarterly newsletter. Cervical dystonia of PSP and limb dystonia of atypical parkinsonism disorders are specifically mentioned.

I’ve distributed the newsletter at recent support group meetings because it has several articles of interest. Here’s the full article and a link to the newsletter.

http://www.apdaparkinson.org/data/NewsL … 202009.pdf –>
article starts on page 1

Botulinum Toxin In Parkinsonism

By Alan Freeman, MD
Associate Professor of Neurology
Emory University School of Medicine, Atlanta, Ga.

Botulinum toxin (BTX) has been successfully used for hyperkinectic movement disorders for more than 20 years. Botulinum neurotoxin is produced by the anaerobic bacillus Clostridium botulinum. There are seven botulinum stereotypes labeled A-G. Two forms of BTX A and B have been approved for clinical use. BTX A is available worldwide as Botox® (Allergan), in Germany as Xeomin® (Merz pharma) and elsewhere as Dysport® (Ipsen). Botox is the only form of BTX-A currently available in the USA, although other forms may be available for therapeutic use next year. A formulation of BTX B is also available in the USA as Myobloc® and in Europe as NeuroBloc® (Solstice). BTX Types C and F have also been used in humans, but only on an experimental basis. The US Food and Drug Administration (FDA) has approved Botox for the treatment of blepharospasm (forced eyelid contractions), cranial nerve seven disorders (hemifacial spasm), cervical dystonia (involuntary neck spasm), and hyperhydrosis (sweating) and Myobloc for the treatment of cervical dystonia.

Other uses of BTX are being investigated, but none has been approved by the FDA. Some of these include spasticity, headache, sialorrhea (drooling), tremor, overactive bladder, limb dystonia, and tics.

BTX works by inhibiting acetylcholine release at the neuromuscular junction and salivary/sweat glands. This causes temporary paralysis of the muscles and a decrease in secretion of the glands. The duration of effect varies but is usually 10-20 weeks (for involuntary movements and excess salivation).

Doses of BTX are dispensed in units. The units of each form of BTX are not clinically equivalent; therefore, the different formulations are not interchangeable. In addition, each formulation has different diffusion and side effect profiles.

Botulinum toxins may be used in idiopathic Parkinson’s disease (PD) as well as atypical parkinsonian syndromes, as progressive supranuclear palsy. Patients who develop blepharospasm, from either the primary illness or medications, can be successfully treated with BTX and are typically injected with small doses of toxin approximately every three

Drooling can be a major problem with advanced PD. Both Botox and Myobloc have been successfully used in this condition. Myobloc may have an advantage, with its side effect of dry mouth, seen when used to treat cervical dystonia. We were recently involved in a Myobloc sialorrhea study for PD, and preliminary results look very promising.

Botulinum toxin can also be used in cervical dystonia in patients with progressive supranuclear palsy, and in limb dystonia with PD and parkinsonian syndromes. This includes the “dystonic clenched fist” in the upper extremity and foot inversion or toe flexion/extension in the lower extremities.

Once the FDA approves new uses for BTX, it will be much easier to get reimbursement from Medicare and insurance companies. Hopefully it will be in the near future.

Note: This article was adapted from one published in the APDA Atlanta, Ga I&R Center newsletter, Winter/Spring 2009. [Robin’s note: I couldn’t find this APDA Atlanta newsletter on the apdaatlanta.org website.]