I get Ultracet from my local Siam pharmacy and they always have me sign for them. The pharmacist told me not to take more than 4 tabs per day, no probs as i only use when i really need and the max i take is 2 tabs per day.
I find they are the only tabs that really do the job, forget Nurofen etc and the other tabs available in 7/11, a waste of time for me.