guanidine hydrochloride

**Guanidine hydrochloride** is a small molecule pharmaceutical agent used primarily to reduce symptoms of muscle weakness and fatigability in patients with Lambert-Eaton myasthenic syndrome (LEMS, also called myasthenic syndrome of Eaton-Lambert)[1][2][4][5]. It is chemically the hydrochloride salt of guanidine (aminomethanamidine) and is often encountered as a white crystalline powder highly soluble in water[1][7]. Its principal mechanism is thought to involve **enhancement of acetylcholine release** at nerve terminals following a nerve impulse[1][5][9]. Additionally, it slows rates of depolarization and repolarization in muscle cell membranes, thereby improving neuromuscular transmission[1][5][9]. Guanidine hydrochloride is not indicated for myasthenia gravis, and use is limited due to side effects and the risk of fatal, dose-related bone marrow suppression[1][2][5]. It is sometimes used in biochemistry as a chaotropic agent for protein denaturation, unrelated to its pharmaceutical use[7].

Brand names

Guanidine

Other names

guanidinium chlorideguanidine HClguanidineaminomethanamidine hydrochloride