The truth is you'll probably fine. I've known of a large number of individuals who have consumed 400mg+ doses for long periods of time.
Yet, l also worked on a wrongful death case where a death occurred from the coprescription of tramadol and antidepressants, the combination of which appeared to result in fatal serotonin syndrome. Who knows what actually happened but based on the coroner's report (the toxicology in particular), and what his wife said (she found him dead on his bed, sheets soaking wet in sweat; ie probable serotonin syndrome), tramadol can be a tricky substance.
I guess the problem is though you probably will, you might not be fine, so take care. Benzo addiction is the bigger danger statistically speaking. Dont take benzos more than once every 10 days to be safe...
I am in a tricky position here as a moderator in that I am aware of the variances that exist between the theoretical and experiental and anecdotal, so while the most conservative harm reductionist would say that the maximum dose is 400mg and no more (based on the literature), I myself would say that higher doses may carry an acceptably higher risk in certain conditions. It is not matter of safer drug use here ultimately...because frankly this site revolves around the notion of a safer way to engage in unsafe behaviors and the dissemination of the methods to mitigate these dangers (ie, safer drug abuse, which is inherently dangerous)...
So again, the answer is clonazepam, but that answer itself brings about more dangers (benzodiazepine addiction).
The biggest bit of harm reduction here is first, dont use benzos with any regularity, and secondarily, avoid heavy tramadol abuse of tramadol if you are on serotonergic drugs or seziure prone (the second of which isn't always clearly known till the shits hit the fan). And third, avoid high dose tramadol abuse overall if possible.