i dont know much about the sedative needed for sn regime but
in my country i can buy chamomile tea, they are Very cheap ~50cents/ 1/2$ per 50 bags. i did cut open 5 bags, and just tossed the fine powderish tea directly with some water, i find it very sedative, kinda like valium. it also feels better i find.. not sure if this helps or if this might be an alternative, but it really reduces anxiety and makes me very sleepy, maybe worth a try if this doesn't counteracts.. there are many different sedatives that you could use if they dont interact with sn in a bad way.
i easily got valium(not sure if this is the right sedative you need), i just had to mention that i have panic attacks often and i gota pretty big stack of them.. maybe you could drop a few+ caffeine and pretend youre anxious, so it might look like a pending panic attack or sort of