Lithium is the one of the drugs of choice for manic depressive illness. Lithium practice guidelines should be followed for every patient before initiating them on lithium therapy. Here we report a case of elderly man with manic depressive illness, who was prescribed lithium, lost follow-up and presented with lithium toxicity- hypothyroidism, nephrogenic diabetes insipidus, sinus node dysfunction. He was managed with parenteral levothyroxine under steroid cover, multiple sessions of hemodialysis and improved. This case report emphasizes the importance of lithium practice guidelines and the responsibility of prescriber to prevent such an event.