Mecamylamine hydrochloride is primarily used in medical settings as a nicotinic acetylcholine receptor antagonist. It is often employed in the treatment of hypertension, particularly in cases where other antihypertensive agents have proven ineffective. The compound works by blocking sympathetic ganglia, leading to a reduction in blood pressure. Additionally, it has been explored for its potential in managing symptoms of Tourette syndrome and certain psychiatric disorders, such as schizophrenia, due to its ability to modulate neurotransmitter activity. In research, it is utilized to study the role of nicotinic receptors in various physiological and pathological processes. Its application in smoking cessation programs has also been investigated, as it may help reduce nicotine dependence by blocking the rewarding effects of nicotine.