Common signs of lithium overdose or poisoning that are often reported can include persistent
diarrhea, along with the following symptoms,
Vomiting or severe nausea
Coarse trembling of hands or legs
Frequent muscle twitching such as pronounced jerking of arms or legs
Blurred vision
Marked dizziness
Difficulty walking
Slurred speech
Irregular heartbeat
Swelling of the feet or lower legs
Even if your lithium levels are not toxic, serious side effects such as the above suggest that your dose may be too high or that lithium is not the right med for you.