The use of low doses of gabapentin in patients with neuropathic pain and with thrombocytopenia

Abstract

Introduction. Approximately 21–27% of patients with blood system diseases receive opioid analgesics, with neuropathic pain being one of the most common reasons for prescription. Gabapentin is used as a first-line drug for neuropathic pain (NP), but has been poorly studied in patients with blood system diseases.The objective was to study the effectiveness and safety of gabapentin in patients with blood system diseases with chronic pain.Materials and methods. A single-center, prospective observational study included 24 patients with thrombocytopenia and pain between October 2017 and October 2022. The patients’ age ranged from 18 to 71 years (median 40 years). All patients with blood system diseases: non-tumor blood system diseases (aplastic anemia) in 8% (n = 2), myeloid tumor blood system diseases (acute myeloid leukemia) in 34% (n = 8), lymphoid tumor blood system diseases (acute lymphoblastic leukemia, follicular lymphoma, diffuse B – large cell lymphoma, T-cell lymphomas, multiple myeloma) in 58% (n = 14). All patients had thrombocytopenia less than 150∙109/l, 66% (n = 16) had less than 90∙109/l. All patients were diagnosed with neuropathic pain (NP), localized according to the neuroanatomical distribution and accompanied by sensory disturbances typical of NP. The localization of pain was different, pain predominated in the lower extremities (63% (n = 15), 95% CI: 43 – 79%), caused by peripheral polyneuropathy of predominantly toxic origin (vincristine, bortezomib), and pain was also caused by the course of the underlying disease: cephalalgia and neck pain, this pain was caused by compression of the nerve structures by the lymph nodes, postherpetic neuralgia, trigeminal neuralgia caused by tumor growth. All patients had intractable, high-intensity pain requiring trimeperidine at a dose of 20–40 mg/day. All patients were prescribed gabapentin therapy at a dose of 900–1200 mg/day.Results. When taking gabapentin in the study group of patients (n = 24), already on the 3rd day, there was a clinically and statistically significant decrease in pain intensity: 1) by median: from the initial 6 to 4 points, p = 0.01 (and up to 3 points by 7th day of therapy) and 2) on average: from initial 6.5 to 3.9 points, p = 0.01 (and up to 3.2 points by the 7th day). Stratification of the dynamics of pain intensity reduction by type of blood system disease (BSD) shows that the decrease by day 3 (sustained and further by day 7) was clinically and statistically significant (p = 0.01) for groups of patients with lymphoid and myeloid BSD, and clinically and approximately statistically significant in patients (n = 2) with non-tumor BSD. Analgesic therapy using small doses of gabapentin gave a pronounced, stable positive effect (pain intensity statistically significantly decreased by an average of 50%). After 7 days of gabapentin therapy, a decrease in the opioid dose was noted in 52% of patients. Side effects were dominated by drowsiness 67% (n = 16), dizziness 32% (n = 8).Conclusion. The results of this study indicate that gabapentin is effective in the treatment of chronic neuropathic pain in patients with BSD and is safe when used in minimal/average therapeutic doses within the daily dosing ranges established by the official instructions for use.