Neurológia pre prax 2/2012

GABRIEL: the implications of a study of prescribing patterns of physicians in treating painful forms of peripheral neuropathies with gabapentin

Study background: Proper management of neuropathic pain is a major part of an outpatient neurologist's everyday practice. Despite an increasing range of active substances used for symptomatic treatment of painful forms of neuropathies of varying aetiology, it is a well-known fact that drugs are not used across the entire therapeutic dosage range and are often insufficiently dosed even in spite of good tolerance and failure to achieve desired relief. Purpose: The primary purpose of the non-interventional clinical trial was to assess the prescribing patterns of neurology specialists in patients with neuropathic pain of varying aetiology in terms of titration and the maximum dose of the drug used. The secondary purpose was to assess the „point of satisfaction” of the physician with the efficacy of treatment with gabapentin as well as to assess the effect of aetiology, co-pharmacotherapy, and possible comorbidities. Methods and results: A prospective multicentre (87 outpatient neurology practices covering the whole area of Slovakia) non-interventional clinical trial in a cohort of 972 adult patients with neuropathic pain of varying aetiology who were either indicated for treatment with gabapentin or continuously treated with gabapentin. An electronic clinical record form (CRF) was used to record the patient's basic medical history and anthropometric data, the intensity (analogue pain scale) and quality of pain and/or of its equivalents and their dynamics in the course of treatment over a period of six months. Initiation of treatment with gabapentin was the case in 841 patients and continuing treatment in 131 patients. There was a predominance of women (61.4%) in the cohort and diabetic neuropathy was the most frequent cause of pain (70.1%). Based on the dose of gabapentin used, the cohort was divided into two groups with an arbitrary dose threshold of 1800 mg (< 1800 mg and ≥ 1800 mg, respectively). Only 98 patients were treated with a dose ≥ 1800 mg; as many as 658 patients were treated with a maximum dose of < 900 mg. Poorly compensated diabetic patients (HbA1c > 7%) required higher doses of the drug to achieve similar therapeutic effect of the treatment. Conclusion: Despite good efficacy of treatment with even lower doses of gabapentin and its good tolerance, the majority of patients used gabapentin in insufficient doses, thus not utilizing the whole therapeutic potential of the drug. Patients with poorly compensated diabetes, which also was the most frequent cause of neuropathic pain, required a higher daily therapeutic dose (DTD) of gabapentin than those with a different aetiopathogenesis of pain, which accentuates the need for tight glycaemic control as a fundamental prerequisite for effective pharmacological symptomatic treatment.

Keywords: neuropathic pain, diabetes mellitus, gabapentin.