Efficacy of a second “drug holiday” in the treatment of intrathecal baclofen tolerance – A case study

Abstract

Spasticity and muscle spasms are common complications following a SCI. Intrathecal baclofen (ITB) infusion is an effective treatment for severe spasticity of spinal cord origin. However, concerns over tolerance remain controversial. It is manifested by an escalation of dose required to produce a previously obtained effect or by a given dose of drug with continued administration. To combat baclofen resistance, a drug holiday is an effective method, interrupting the trend of accelerated dosage by weaning off the baclofen during 4–6 weeks. We report a case of a 45-year-old patient who suffered an accident on 1996 with SCI. He has incomplete tetraplegia AIS B, motor level C5 and sensitive L1. Due to severe uncontrolled spasticity (MAS = 4), he was implanted with a ITB pumb in 2002. Since than, it remained controlled (MAS = 2) with 310 ug/day. In 2009, because the resurgence of severe spasticity (MAS = 5), resistant to a fast increase on daily dose of baclofen until 360 ug/day, drug tolerance was suspected. We conducted a drug holiday over 4weeks and reintroduce baclofen. With 220 ug/day he showed a good control of spasticity (MAS = 1). During 2017, he presented an increase in spasticity (MAS = 4), combined with clonus of lower limbs [Spasm Frequency Scale (SFS) = 2]. We tried to control it, increasing the daily dose of baclofen, without response. He was admitted in CMRA for a second drug holiday. After 4 weeks without any baclofen, we gradually refill the pump. With 60ug/day we noticed an improvement on lower limbs spasticity (MAS = 2) and a decrease on muscle spasms (SFS = 0). He was discharged with this dose, appreciably below from admission. The use of ITB is increasing so we want to highlight the importance of being aware for cases of tolerance to baclofen. In this case, both drug holidays were effective, as measured by MAS and SFS.