Most Parkinsonism related pain can be assigned to one or more of five categories: musculoskeletal pain, neuritic or radicular pain, dystonia associated pain, primary or central pain, and akathitic discomfort. In PD pain tends to affect the side of the body that was initially, or more severe affected by the motor symptoms. Botulinum toxins are an effective treatment modality for a growing number of neurological conditions. They have been studied for a variety of conditions associated with PD including dystonia, jaw tremor, apraxia of eyelid opening, camptocormia, dyskinesias, freezing of gait, sialhorrea, overactive bladder and constipation. There are no studies for the use of Botulinum Toxin for pain in PD. The investigators will perform a double-blind, randomized cross-over study evaluating the efficacy and safety of an individual pattern of BTXA injections targeted at painful muscles vs. placebo injection.

The investigators will perform a double-blind, randomized cross-over study evaluating the efficacy and safety of an individual pattern of BTXA injections targeted at painful muscles vs. placebo injection. Primary outcome will be a measure of global pain as perceived by the participants. To assess this endpoint the investigators will use:1.

change in pain on a Numeric Rating Scale (NRS) by telephone between BTXA and placebo injections at 4 week post injection and 2.change in Visual Analogue Scale (Edmonton Symptom Assessment System: Numerical Scale) at study visits.

Secondary outcomes will be the percentage of responders, Physician rated Clinical Global Impression (CGI), Unified Parkinson Disease Rating Scale (MDS-UPDRS) on medication, quality of life by Parkinson Disease Questionnaire (PDQ-39) and adverse events as assessed at each study visit.

Inclusion Criteria:

• Subjects with advanced PD (Hoehn and Yahr 3-5) and painful limbs not responding to antiparkinsonian agents sufficiently.
• BTXA treatment naÃ-ve patients or not received any within last 12 months (including other indications).
• Stable PD and pain medications for at least 30 days
• Competence to self-report pain severity in a Visual Analogue Scale (VAS)

Exclusion Criteria:

• Subjects with a primary cause of pain unrelated with PD and associated with another medical condition e.g. severe arthritis

• Subjects that because of the severity or refractory pain are under an unfixed analgesic schedule

• Subjects unable to self- report pain severity in a VAS

• Subjects undergoing acute infections or other acute intercurrences.

• Any contraindication to receiving BTXA injections:

  1. Subjects who are hypersensitive to any BTXA or to any ingredient in the formulation or component of the container (Clostridium Botulinum toxin type A neurotoxin complex 900 kD, Human Serum Albumin and Sodium Chloride).
  2. The presence of infection at the proposed injection site(s).