Botulinum toxin is mainly used in cosmetic dermatology for short term treatment of wrinkles associated with old age. Major opportunity and growth lies here IMHO.
Botulinum toxin prevents the release of neurotransmitter acetylcholine in the synapses, which in turn causes relaxation of the muscle implicated.
And it is a very deadly toxin, infact it is the most potent toxin known to mankind(Paralysis of respiratory muscles causes respiratory failure and death). It’s minimum lethal dose is 1-2ng/kg if given intramuscularly or intravenously. That means, 60g of toxin is enough to kill the entire mankind (7.8 billion people). So the therapeutic dosage of the toxin is very much lower.
Therapeutic use of botulinum toxin is based on it’s inhibitory effect on the synapse and relaxation of the muscle. Therefore whichever condition where there is muscle spasm and we need muscle relaxation, we can use this toxin. But the catch here is, the action is short lived and you need to re-inject every 4-6 months. Also, the accessibility of the muscle for injection also comes into picture.Treatment is comparatively easy for facial muscles for treatment of wrinkles. But whenever you need to give injections endoscopically to inaccessible muscles every 5-6 months, it is obviously not the first choice of treatment. For instance, botulinum toxin ‘can be’ used for the treatment of achalasia cardia by relaxing the lower esophageal sphincter. But it is not preferred as a first choice because you need to inject the toxin endoscopically every 5-6 months. So it is reserved for those patients who can’t be surgically treated. Similarly in the treatment of overactive bladder, medications which relaxes the bladder are preferred first.
Botulinum toxin has been approved for the treatment of chronic migraine in recent past. But you should understand that, there is very effective new treatment modalities emerging for the treatment of acute migraine and it’s prevention.( Monoclonal antibodies and small molecules which blocks the activity of CGRP). Episodic migraine treatment and prevention is 90% of the market and chronic migraine treatment only constitutes 10%.
Major revenue for botulinum toxin is from cosmetic dermatology. Global botox net revenues for Allergan aesthetics were $1.12 billion on 2020.
Novel botulinum toxins and improved formulations are on pipeline for Allergan aesthetics.
In cosmetic dermatology also, the dosage of the toxin is very low. 100 units of the botulinum toxin containing 4.8 ng is usually used. So the volume needed for commercial preperation is very less.
Botulinum toxin is also used in the treatment of blepharospasm and Palmar Hyperhidrosis(sweaty palms). In palmar hyperhidrosis also, medical treatment with topical Glycopyrrolate is commonly used than botulinum toxin.