Guaifenesin - Muscle Relaxant - Upper Back Pain

Inclusion Criteria:

- Paticipant presents with a new episode of acute upper back/neck/shoulder pain and
muscle spasm that:

1. is at least 30 days from previous episode.

2. has an onset occurred within 48 hours of Visit 1.

3. has symptoms consistent with a clinical diagnosis as per the physical
examination at Visit 1.

4. has a subject-rated muscle spasm score and a pain score of at least 40 out of
100 on a 100mm VAS.

- Paticipant has a normal neurological examination.

Exclusion Criteria:

- Medical history: a) Paticipant has a known or suspected intolerance or
hypersensitivity to guaifenesin or methocarbamol (or closely related compounds) or
any of their stated ingredients. b) Paticipant has history of upper back pain with
active hypersensitive spots - trigger point in the muscles of upper
back/neck/shoulder/maxillofacial regions. c) Paticipant has a current or recent
history of liver and/or kidney disease, neck/back/shoulder injuries, spinal disc
disease, myocardial infarction (<12 months from Visit 1) and osteoporosis. d)
Subjects have history of other chronic pain e.g. headache, osteoarthritis, arthritis,
lower back pain etc.

- Medications: a) Paticipant has used a muscle relaxant or narcotic within 2 weeks of
Visit 1. b) Paticipant has used monoamine oxidase inhibitors or selegiline within 2
weeks of Visit 1 c) Currently using tricyclic antidepressants, lithium,
anticoagulants, or tramadol.

- Paticipant is involved in a workers compensation case.

- Paticipant is unlikely to refrain from using analgesics, NSAIDs, and other muscle
relaxants for the duration of the study, with the exception of cardioprotective doses
of aspirin (i.e., ≤ 325 mg/day).

- Paticipant is unlikely to refrain from physical therapy, massage therapy,
acupuncture, heat treatment, spas, etc for the duration of the study.