Botulinum toxin A (BTX-A) is widely used in the management of muscle spasticity in children. However, at present the dose of BTX-A for a given patient is selected empirically. The aim of this study is to provide dosage guidelines that are based on risk/benefit assessment. This was a multicentre retrospective study of the safety profile and efficacy of BTX-A in children with chronic muscle spasticity. Data in 758 patients who received a total of 1594 treatments were analysed (mean age 7.2 years; 429 males, 329 females). Spastic cerebral palsy (CP) was the most common diagnosis (94% of the study sample). Of all treatments 7% resulted in adverse events; incidence was related to the total dose rather than the dose calculated on the basis of body weight. The highest incidence of adverse events was observed in patients who received >1000 IU of BTX-A per treatment session. The odds of an adverse event was 5.1 times greater for this group of patients than for those who had 250 IU or less (p<0.001). A good overall response to treatment was reported in 82% and treatment goals were fully or partially achieved in 3% and 94% of participants respectively. More patients in the highest dose group reported functional deterioration. Interestingly, multilevel treatments resulted in a better response than single-level treatments (odds ratio 1.7, 95% CI 1.3 to 2.2,p=0.001).

In this study, we compared the long‐term efficacy and tolerability of two dosage regimens of the potent botulinum toxin type A (BoNT‐A; Dysport; Ipsen Ltd, Slough, UK) in children with cerebral palsy (CP) and lower‐limb spasticity. Children aged 1 to 8 years with diplegic CP who were able to walk (aided or unaided) were randomized (1:1) to 30 LD50 units/kg total body weight of BoNT‐A (injected into gastrocnemius muscles) every 4 months or once yearly for 2 years in this multicentre, assessor‐blinded, parallel‐group study. In the 4‐monthly group (n=110, 39 males, 71 females), mean age was 3 years 8 months (SD 1y 6mo, range 1–8y). In the yearly group (n=104, 47 males, 57 females), mean age was 4 years 4 months (SD 1y 6mo, range 2–8y). Both treatment groups had similar baseline Gross Motor Function Measure scores. At month 28 (primary endpoint; intention‐to‐treat group), median maximum passive ankle dorsiflexion was 12.00° in the 4‐monthly and 11.00° in the yearly group. Between‐group difference of 1.67° was not statistically significant (p=0.055). Other efficacy endpoints showed no significant difference between the regimens. The results of the study do not allow a clear conclusion of the preferred injection regimen.

Botulinum toxin A (BTX‐A) is widely used in the management of muscle spasticity in children. However, at present the dose of BTX‐A for a given patient is selected empirically. The aim of this study is to provide dosage guidelines that are based on risk/benefit assessment. This was a multicentre retrospective study of the safety profile and efficacy of BTX‐A in children with chronic muscle spasticity. Data in 758 patients who received a total of 1594 treatments were analysed (mean age 7.2 years; 429 males, 329 females). Spastic cerebral palsy (CP) was the most common diagnosis (94% of the study sample). Of all treatments 7% resulted in adverse events; incidence was related to the total dose rather than the dose calculated on the basis of body weight. The highest incidence of adverse events was observed in patients who received >1000 IU of BTX‐A per treatment session. The odds of an adverse event was 5.1 times greater for this group of patients than for those who had 250 IU or less (p<0.001). A good overall response to treatment was reported in 82% and treatment goals were fully or partially achieved in 3% and 94% of participants respectively. More patients in the highest dose group reported functional deterioration. Interestingly, multilevel treatments resulted in a better response than single‐level treatments (odds ratio 1.7, 95% CI 1.3 to 2.2, p=0.001).