I don't think so, his magic will be use to named some monsters or demon, but it will recover back as time pass. Remember when Rimuru named everyone for the first time?? His magic was drained and went into sleep mode, but he woke up after 3 days or so.
ohh i see. i thought he went to sleep mode that time cuz he grew weak or something. glad to know our slime is still OP even after all that naming (⌒▽⌒)
I don't think so. Rimuru just weakens temporarily in naming monsters so when he carelessly name monsters his magicules depletes, and if not monitored properly, he could be in danger because monsters are fundamentally made of magicules.
Unlike before when veldora was inside him, whenever he's running low on magicules, veldora provides his own so Rimuru would be safe.
I love it when he's totally OP. ε=ε=(ノ≧∇≦)ノ
Veldora explained that the reason Rimaru didn't have any other side effects from Naming, apart from basically going into sleep mode, is because he took the excess magicules from Veldora (who was in his stomach and so was used as 'material'), if Veldora hadn't been in his stomach Rimuru would have died from the Namings - he simply didn't have enough magicules pre-demon lordification.
His OP-ness came from his uniqueness (such as his Unique skill), and now he's just straight OP
http://www.mangago.zone/read-manga/tensei_shitara_slime_datta_ken/bt/mpn_chapter-2313775/pg-21/
so whenever rimuru names someone, does he become weak or something? like if he names a lottt will he become weak and be completely depleted of magic permanently?