[Clenbuterol in amyotrophic lateral sclerosis. No indication for a positive effect]

The anabolic effects of clenbuterol have been recognized for a long time. Clenbuterol augments the expression of specific muscle proteins with a differential effect on type I and type II fibres. Furthermore, clenbuterol induces the synthesis of endogenous nerve growth factor (NGF) and may itself be a myotrophic factor released by neuron endings. Side effects include tremor and headache and dose dependent abnormalities of laboratory values (hypokalemia, hypoglycemia). After long-term medication increasing fatigue of muscles has been observed. Decreased expression of beta 2-adrenergic receptors may limit the expected functional improvement. The efficacy of clenbuterol as symptomatic treatment of amyotrophic lateral sclerosis has not been proved. Controlled treatment trials are warranted to assess this question.