Effect of salbutamol on respiratory muscle strength in children with SMA: A pilot study

Abstract

Background: Oral salbutamol has shown clinical benefits in spinal muscular atrophy (SMA). However no study assessed its effect on respiratory muscles. Aims and objectives: We studied the effect of oral salbutamol on the respiratory muscle strength in children with SMA and searched for possible outcome measures for future therapeutic trials. Methods: Lung function and respiratory muscle function were assessed in children affected by different types of SMA and receiving daily oral salbutamol for at least one year. The respiratory data charts (n=21) of 11 SMA type II historical controls were selected in order to match the mean age of the SMA II and II-III intermediate patients receiving salbutamol. Results: Four boys and 3 girls (6.4±2.0 yrs old, range 4-10 years old; 1 SMA I-II intermediate, 4 SMA II, 1 SMA II-III intermediate and 1 SMA III) treated by oral salbutamol (duration 23±8 months) were assessed. Treatment was well tolerated by all patients. Maximal static inspiratory pressure, sniff nasal inspiratory pressure and slow vital capacity were significantly better in the salbutamol treated SMA II and II-III group compared to controls (p Conclusions: Long term oral salbutamol showed benefits in motor and respiratory function in children with SMA and appeared to increase the strength of the inspiratory muscles in a small cohort of SMA II and II-III patients.