in over dosage causes somnolence, coma
and cardiac dysrhythmias.
Any thing more than he usual dosage can cause exces sleepness.
Ten 400 mgs Tablets, i.e 4000 mgs will cause excess sleepiness and drowsyness.
It will not lead to immediate death. Also if taken to hospital, patient can be stablised and will improved with time
Hope this answers your query