Efficacy, safety and tolerance of subcutaneous injection of high dosages of diclofenac in patients with neuropathic non-cancer pain and neuropathic cancer pain: Data from a clinical setting

Abstract

Diclofenac sodium is widely used for its anti-inflammatory and analgesic effects in the symptomatic treatment of acute and chronic inflammatory and painful conditions. The present observational study was carried out to investigate efficacy, safety, and tolerability of a new subcutaneous (SC) 75 mg/1 mL diclofenac hydroxypropyl-β-cyclodextrin (HPβCD) formulation for the treatment of neuropathic pain both in patients without cancer and in patients with cancer. A total of 105 outpatients and inpatients with moderate to severe neuropathic pain related to cancer (CP) and non-cancer (NCP), were selected if Numeric Rating Scale (NRS) ⩾7 and Pain Detect (PD) >16, and treated with 75 mg/1 mL SC HPβCD, according to a real clinical setting. The analgesic efficacy of the treatment, which was assessed during the study by questionnaire, was expressed in terms of reduction of 30–50% and >50% of baseline pain (NRS), after 1.5 h and 4 h from drug administration; tolerability and safety were assessed as well, and adverse events were recorded by an expert panel. In our study, a significant reduction in pain intensity (PI) after 1.5 h and after 4 h was observed for both groups of patients (CP and NCP). Different from what was detected in the CP group, a further and significant reduction of PI was obtained in the NCP group at 4 h ( P <0.039). With regard to tolerability, while 90% of the patients did not complain of any adverse drug reactions, only 10% reported mild transient adverse reactions. SC administration of HPβCD has been proven effective and safe in the treatment of patients with moderate to severe neuropathic pain related to cancer or not, in a real clinical setting.