You are expressing fear of Imitrex and inconsistency in using any med in a pattern which is likely to give good, enduring relief.
I'd suggest working with a headache specialist who can work out a treatment plan which would deal with these issues.
Starting and stopping your meds is, with Cluster, not the approach which is, for the long term, useful. The preventive med, especially, will be help you when you work up to an effective dose (and that may take dosage adjustments and months of trial to determine) and then stay there for a good run. Your body then has a chance to stabalize so that you and the doc can see what is really the best package for you.
Re. Imitrex: unless you have a heart condition, the safety record is good. If you want to discuss options with your doc, print out the file in PDF, below, and use it as a tool to review your choices.
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LOCATING HEADACHE SPECIALIST
1. Search the OUCH site (button on left) for a list of recommended M.D.s.
2. Yellow Pages phone book: look for "Headache Clinics" in the M.D. section and look under "neurologist" where some docs will list speciality areas of practice.
3. Call your hospital/medical center. They often have an office to assist in finding a physician. You may have to ask for the social worker/patient advocate.
4. Multimedia File Viewing and Clickable Links are available for Registered Members only!! You need to

or

; On-line screen to find a physician.
5. Multimedia File Viewing and Clickable Links are available for Registered Members only!! You need to

or

Look for "Physician Finder" search box. They will send a list of M.D.s for your state.I suggest using this source for several reasons: first, we have read several messages from people who, even seeing neurologists, are unhappy with the quality of care and ATTITUDES they have encountered; second, the clinical director of the Jefferson (Philadelphia) Headache Clinic said, in late 1999, that upwards of 40%+ of U.S. doctors have poor training in treating headache and/or hold attitudes about headache ("hysterical female disorder") which block them from sympathetic and effective work with the patient; third, it's necessary to find a doctor who has experience, skill, and a set of attitudes which give hope of success. This is the best method I know of to find such a physician.
6. Multimedia File Viewing and Clickable Links are available for Registered Members only!! You need to

or

NEW certification program for "Headache Medicine" by the United Council for Neurologic Subspecialties, an independent, non-profit, professional medical organization.
Since this is a new program, the initial listing is limited and so it should be checked each time you have an interest in locating a headache doctor.