• Pain control rate [ Time Frame: within 15 days ] [ Designated as safety issue: No ]
• Reduction of Break Through Pain number [ Time Frame: within 15 days ] [ Designated as safety issue: No ]
• Record of adverse events [ Time Frame: within 15 days ] [ Designated as safety issue: Yes ]
• Reduction of allodynia in patients presenting it at T0 [ Time Frame: within 15 days ] [ Designated as safety issue: No ]
• Patient satisfaction [ Time Frame: within 15 days ] [ Designated as safety issue: No ]
• Assessing whether COMT and mu blood polymorphisms are associated to response [ Time Frame: within 15 days ] [ Designated as safety issue: No ]

The aim of the study is to assess tolerability and activity of oxycodone and pregabalin in combination for the treatment of oncological neuropathic pain with two different strategies.

Neuropathic pain is frequently diagnosed as a complication of cancer pain. While opioids are the mainstay of cancer pain management,their efficacy in neuropathic pain seems to be less then optimal,and adjuvant drugs, mainly anticonvulsants and antidepressants,are often combined with opioids in the analgesic regimen of patients with neuropathic cancer pain. This approach is suggested by well-established guidelines, but the analgesic benefit and the safety of pregabalin and oxycodone in combination is not yet documented.

The aim of this study is to assess the activity and tolerability of the addition of pregabalin to oxycodone in the treatment of patients with neuropathic pain due to neoplasm.

• Cancer
• Pain

• Drug: oxycodone
• Drug: pregabalin

• Experimental: oxycodone 20 mg/day plus pregabalin at increasing dose starting from 50 mg/day for 15 days or until unacceptable toxicity develops
• Active Comparator: pregabalin 50 mg/day plus oxycodone at increasing dose starting from 20 mg/day. For 15 days or until unacceptable toxicity develops

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Inclusion Criteria:

• instrumental and clinical diagnosis of every malignant neoplasm
• presence of pain with a neuropathic component in the opinion of the physician
• presence of pain >=4(NRS)
• PS ECOG <3
• written informed consent

Exclusion Criteria:

• serum creatinine >2mg/ml or creatinine clearance <40 ml/min
• mild or severe hepatic insufficiency
• iatrogenic neuropathy caused by chemotherapeutic agents
• previous allergic reactions to oxycodone and pregabalin
• pregnancy or breastfeeding