Life-Threatening Constipation Induced by Intrathecal Baclofen Therapy

drugs (4 azathioprine, 2 methotrexate, 1 interferon beta-1b, 8 gabapentin, 2 pregabalin, 2 phenobarbital, 2 paroxetine, 1 citalopram, 1 venlafaxine, 7 furosemide, 4 heparin, 1 risperidone and 1 olanzapine). Fifteen patients did not receive any concomitant medication. ITB was administered with a mean effective daily dose of 251.3 8 11 g (range 90–580 g). Adverse events of ITB were monitored by evaluating patients’ monthly records and constipation was defined as Dear Sir, Intrathecal baclofen (ITB) delivery is a therapeutic option for patients with severe spasticity not responding to common oral medications, such as baclofen, dantrolene or tizanidine. At common doses, ITB is usually tolerated by patients [1] . Unfortunately, higher doses could be necessary to treat many cases of spasticity, thus enhancing the frequency of side effects [2–4] . Concerning gastrointestinal function, ITB could affect peristalsis, which could be severely slowed down to paralytic ileus. Nevertheless, constipation has previously been reported as an infrequent ITB-induced adverse effect, ranging from 3 to 10% of treated patients [2–4] . Here we report that, in our series of patients treated with ITB, constipation was a frequent and serious side effect, leading to death in 1 case. Thirty-eight patients (26 men and 12 women; age 48.7 8 15.4 years, mean 8 SD) were implanted for continuous ITB infusion from August 2002 to July 2006. They had severe spasticity due to different neurological diseases. Thirty-six patients out of 38 (95%) were affected by spinal cord diseases (myelitis, n = 19; multiple sclerosis, n = 13; traumatic injury, n = 4). The remaining 2 patients suffered from spasticity due to anoxic encephalopathy. All patients had previously been treated with oral baclofen, dantrolene, or tizanidine at their optimal doses, without relevant clinical benefit. Twenty-three out of 38 patients (61%) were on treatment with other Received: June 27, 2007 Accepted: October 9, 2007 Published online: June 14, 2008