Clenbuterol, a β-Adrenoceptor Agonist, Increases Relative Muscle Strength in Orthopaedic Patients

Abstract

1. The sympathomimetic agent clenbuterol has a muscle-specific anabolic effect in normal and wasted muscles from animals. This trial was designed to examine the effect of the drug on the recovery of muscle strength and area after open medial meniscectomy. 2. A double-blind, completely randomized, placebo-controlled study was carried out on 20 healthy male patients. Muscle strength and cross-sectional area were determined before and after surgery. Patients were treated with drug or placebo for 4 weeks postoperatively and there was a 2 week washout period. 3. The results suggest that, in the operated leg, clenbuterol treatment is associated with a more rapid rehabilitation of strength in knee extensor muscles; in the unoperated leg, knee extensor strength increased above the initial values after 6 weeks (P = 0.01). However, in terms of absolute strength the differences were not significant between the two groups. 4. It is concluded that the data lend support to the proposition that clenbuterol has therapeutic potential in the treatment of muscle-wasting conditions.

Power output of fast and slow skeletal muscles of mdx (dystrophic) and control mice after clenbuterol treatment

“…Although the potential therapeutic role for clenbuterol in muscular dystrophy has received much attention (Maltin et al 1987(Maltin et al , 1993Martineau et al 1992;Zeman et al 1994;Hayes & Williams 1994;Dupont-Versteegden et al 1995), the majority of these studies have investigated only whether clenbuterol alters the mass and isometric force-producing capacity of isolated muscles. Whether clenbuterol affects the dynamic properties of dystrophic skeletal muscle has not been addressed.…”

Regulation of SMN Protein Stability

“…It has been previously reported that SMN is phosphorylated at serines 28 and (8,12,14). ␤-Adrenergic agonists have been shown to improve muscle strength in human subjects with healthy and diseased muscle (29)(30)(31), and daily albuterol treatment had beneficial effects in an open-label pilot study in SMA type II and III patients (16). Salbutamol has been also been shown to increase SMN protein levels in patient-derived fibroblasts (1).…”

β2-Agonist fenoterol has greater effects on contractile function of rat skeletal muscles than clenbuterol

“…Orthopedic patients administered 20 g clenbuterol twice daily for 4 wk did not exhibit any improvement in the absolute strength of their knee extensor muscles compared with patients given placebo (27). A 3-mo pilot trial of albuterol (16 mg/day) given to 15 patients with facioscapulohumeral muscular dystrophy led to improved maximum voluntary isometric contractile performance, and this was followed by a year-long randomized, double-blind, placebocontrolled trial where patients were treated with up to 16 mg of albuterol twice daily (20).…”

“…The potential for ␤ 2 -agonists to improve the size and strength of muscles of human patients affected by neuromuscular diseases has received only limited attention (20,27). Orthopedic patients administered 20 g clenbuterol twice daily for 4 wk did not exhibit any improvement in the absolute strength of their knee extensor muscles compared with patients given placebo (27).…”