My Wife totally Removed thyroid 2 years ago

My Wife totally Removed thyroid 2 years ago and she used to take Eltroxin tablets 150/day and 100/day
everything was going ok and TSH tests was normal ranges
till last Month we made TSH test and results was H 6.19 she Decided to increase Eltroxin to 200/day and 150/day ( because she knows that Eltroxin tablets Is inversely proportional to TSH )
so she want to low down TSH level …….(after 1 month with dusage 200 and 150 )
we made TSH test results L 0.01 ) and she got sick,Fast heartbeat,sweating and fatigue .
she came back to take only 1(100 Eltroxin /day )

so now what is the good advice ?
decrease Eltroxin dose or what to get TSH back to normal range ?
what is the good dose for Eltroxin