Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. It is not safe to take Haldol drug together with Lithium drug. Taking Haldol together with Lithium drug can increase the levels of Lithium which can cause harmful effects such as abnormal rhythm of your heart, tiredness, fainting, confusion, tremors, increased frequency of urination, acne, fever, and thyroid dysfunction. You may need a dose adjustment or special tests to monitor if you use both medications. Taking Haldol together with sleeping meds may increase side effects such as drowsiness, confusion, difficulty concentrating, motor incoordination which may result in falls and injuries. Lithium may occasionally affect blood glucose levels. Both hyperglycemia (high blood sugar) and, less frequently, hypoglycemia (low blood sugar) have been reported. Your blood glucose should be closely monitored during treatment with Lithium so that your diabetic regimen may be adjusted if needed. Let your doctor know if you experience hyperglycemia or hypoglycemia, or if you notice a loss of blood glucose control. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Mohammed Taher Ali