I have epilepsy, and am currently taking topamax and keppra, (levetiracetam) will either rhodiola or 5-thp have any interaction with my meds, or epilepsy?

One at a time. While Keppra (levetiracetam) and topamax do not interact, it is never wise to introduce to variables, in this case rhodiola and 5-htp. There is some evidence that 5-htp can reduce seizure activity, however it is the agent most likely to interact with your other meds. Also, 5-htp can cause GI side effects because of the plethora of receptors in the gut. Rhodiol is a neuroadaptagen that can reduce brain stress.
SEE BELOW. The Keppra (levetiracetam) will be unlikely to have any drug-drug interactions, but the topamax, being metabolized in the liver might. Maybe best question is "why do you need rhodiola or 5-htp?". Talk to your neurologist first, before modifying any of you supplements or meds.