Efficacy and Safety of Cyclobenzaprine Hydrochloride Extended Release for the Treatment of Chronic Migraine

Inclusion Criteria:

1. males and females, aged 18 to 65, with headaches longer than 30 minutes per day for atleast 15 days per month (28 days) meeting ICHD-IIR criteria for chronic migraine.Subjects must have headaches at least 8 days per month which are alleviated withtriptans or ergots AND/OR which have at least 1 migrainous feature (unilaterality ofheadache or pain more prominent on 1 side of the head, throbbing, nausea, vomiting,photophobia, phonophobia, increased pain with physical exertion or avoidance ofexertion)

2. subjects willing and able to perform all study-related measures including accuratelycompleting study diaries and instruments, maintaining stable doses of headachepreventative medications, completing study visits and obtaining blood testing asindicated.

3. women of childbearing potential must use an acceptable method of birth control for theduration of the study (oral contraceptives, IUD, injectable or intravaginalcontraception or barrier methods combined with spermicide)

Exclusion Criteria:

1. subjects <18 and >65 years of age

2. pregnancy or attempted pregnancy during the study

3. nursing females

4. psychiatric condition which, in the investigator's opinion will influence trial safetyor data collection

5. new daily persistent headache, hemicrania continua, chronic tension-type headache orcluster headache diagnoses.

6. headache suspicious for and not investigated to rule out secondary headache disorder

7. angle closure glaucoma

8. urinary retention

9. hepatic impairment felt by the investigator to interfere with study safety (asdetermined from history and/or prerequisite liver function testing within 1 year ofstudy enrollment)

10. within 14 days of MAO inhibitor use or discontinuation

11. known hypersensitivity to cyclobenzaprine hydrochloride or any component of Amrixformulation

12. concomitant tramadol or tricyclic antidepressant use

13. history of myocardial infarction or congestive heart failure

14. hyperthyroidism

15. new start of daily preventative medication (which may influence headaches) less than 2months preceding enrollment

16. dosage change or discontinuation of daily preventative medication (which may influenceheadaches) within 1 month of trial enrollment -