ALS untangled #83: clenbuterol.

ALS Untangled reviews alternative and off-label treatments for people living with amyotrophic lateral sclerosis (PALS). Here we review clenbuterol, a β-2 adrenergic agonist, as a potential treatment for amyotrophic lateral sclerosis (ALS). Clenbuterol has biological effects that could be relevant to the pathophysiology of ALS such as inducing muscle hypertrophy, improving mitochondrial function, and reducing neuroinflammation. Two studies in mouse models of motor neuron disease and two open label trials suggest possible benefits. However these have methodological flaws which limit interpretation. Clenbuterol can have an array of side effects, some severe. Drop-outs due to side effects were very common in one of the ALS trials and in a separate expanded access program. Based on this information, we cannot currently endorse clenbuterol as an ALS treatment, but we do hope to see further studies of it, or another long acting β-2 adrenergic agonist in people with ALS.