Botulinum toxin in primary care medicine.

Clostridium botulinum, a gram-positive anaerobic bacterium, produces a potent neurotoxin that causes muscle paralysis. The therapeutic use of botulinum toxin was discovered in the 1970s and has since been used to treat patients with a broad range of medical complaints. Botulinum toxin (BTX) is used in the primary care setting to treat conditions such as allergic rhinitis, hyperhidrosis, lichen simplex chronicus, migraine, myofascial pain syndrome, and certain task-specific idiopathic focal dystonias (eg, writer's cramp)--in addition to its more publicized use for cosmetic enhancement of the face. The expanding range of therapeutic applications for BTX make it necessary for primary care physicians to understand the biochemistry, preparation, indications, and interactions of BTX.