If I take diazepam before taking my SN will it negatively interact with the tagamet or meto or should it be fine? Also how many should I take would 10 or 20 be fine, I haven't taken any in a long time so even 5 should probably knock me out pretty good
Diazepam or any benzo will not interact with SN. Benzos are completely optional for the SN method but if you have them, take them. Meto interacts with benzos but does so in a way that makes them stronger, so the result will be more sleepy more better. 
