Physostigmine hemisulfate is primarily used in medical settings as a reversible cholinesterase inhibitor. It is applied to treat conditions like glaucoma by reducing intraocular pressure. Additionally, it is utilized to reverse the effects of anticholinergic drug overdoses, helping to restore normal nervous system function. In some cases, it is also employed in the management of myasthenia gravis to enhance muscle strength. Its ability to cross the blood-brain barrier makes it effective in addressing central nervous system issues related to anticholinergic toxicity.