http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000403/
Check out the "side effects"
Symptoms of overdose may include:
drowsiness
inappropriate happiness
sharper senses than usual
changed awareness of time
red eyes
fast heartbeat
memory problems
feeling that you are outside of your body
mood changes
difficulty urinating
constipation
decreased coordination
extreme tiredness
difficulty speaking clearly
dizziness or fainting when standing up too fast
There are fewer side effects from this drug then there are on my thyroid meds.