Botulinum toxin: a dreaded toxin for use in human being.

Botulinum toxin is a dreaded biological toxin elaborated by Clostridium botulinum. The action of this toxin is to cause paralysis of both voluntary and involuntary muscles. The unique property of paralysing capability of muscles has been used for the benefit of human beings. Dr Allan Scot, an ophthalmologist, first used the toxin in a patient with squint in 1981 and since then the botulinum toxin is being used in various disorders characterised by muscle overactivity such as spasticity in both children and adult, dystonic conditions such as blepharospasm, cervical dystonia, spasmodic dysphonia, writer's cramp, etc, hemifacial spasm and headache. Its main action is at the terminal nerve endings of myoneural junction and it prevents release of acetylcholine from vesicles thus causing chemical denervation. Its action persists for 3 to 4 months on an average. Its side effects such as drooping, diplopia, dysphagia, depending on the sites of injection, are few and usually transient. Generalised anaphylaxis is almost unknown. Now botulinum toxin is being used in non-neurological conditions where muscles are under spasmodic state such as achalasia cardia, anal fissure, spasm of urethral sphincter, etc. Because of wider safety range and fewer complications, botulinum toxin has been an important therapeutic armamentarium in different branches of medicine and surgery.