Pharmacological Treatment Patterns in Neuropathic Pain-Lessons from Swedish Administrative Registries

Objective. To explore the treatment patterns of patients with a diagnosis related to chronic pain (DRCP) initiating pharmacological treatment indicated for neuropathic pain (NeuP: tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors, and anticonvulsants). Design. Retrospective study on administrative registers. Setting. General population in Western Sweden (one sixth of the country). Subjects. All patients with a DRCP (N = 840,000) in years 2004-2009. Outcome Measures. Treatment sequence, continuation, switching, and comedication. Results. In total, 22,997 patients with a first NeuP in 2007 or 2008 were identified, out of which 2% also had epilepsy and 39% had a mood disorder. The remaining 13,749 patients were assumed to be treated for neuropathic pain, out of which 16% had a neuropathy diagnosis, 18% had a mixed pain diagnosis, and the remaining 66% had another DRCP. The most common first prescription was amitriptyline (40%) followed by pregabalin (22%) and gabapentin (19%). More than half had discontinued treatment after 3 months, and 60-70% at 6 months. Seven percent received another NeuP drug within 6 months of the discontinuation of their first NeuP treatment, 11% had another analgesic and 22% had a prescription indicating psychiatric comorbidity (selective serotonin reuptake inhibitors or benzodiazepine). Conclusions. Treatment initiation of currently available drugs indicated for neuropathic pain less frequently lead to long-term treatment in clinical practice compared with clinical trial, and few try more than one drug. We suggest our findings to be indications of a need for better routines in diagnosing patients to ascertain optimal treatment and follow-up.