It is not infrequent to see both these medications to be prescribed to a patient with fibromyalgia. Medications can be used for multiple different disorders...yes it is true these medications can be used for seizures, but they can be used for different disorders as well. For example, gabapentin may also be used for chronic pain (ie. fibromyalgia), and klonopin can potentially have some benefit in fibromyalgia as well (may possibly improve sleep, a common problem in fibromyalgia, reduce anxiety, potentially improve functionality). A potential concern with the combination of these medications are the additive effects of their sedation (they are both sedating)..over sedation can increase the risk of falls, and potentially cause breathing to stop when sleeping (if you have untreated sleep apnea). otherwise these medications are generally fine to take together