Clenbuterol in amyotrophic lateral sclerosis. No evidence for therapeutic efficacy

The anabolic effects of denbuterol have been recognized for a long time. Cl enbuterol augments the expression of specific muscle proteins with a differ ential effect on type I and type II fibres. Furthermore, clenbuterol induce s the synthesis of endogenous nerve growth factor (NGF) and may itself be a myotrophic factor released by neuron endings. Side effects inclde tremor a nd headache and dose dependent abnormalities of labaratory values(hypokalem ia,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.