Levetiracetam as an adjunctive analgesic in neoplastic plexopathies: case series and commentary.

Certain types of pain associated with cancer may be difficult to treat with standard therapies, often resulting in intractable pain and suffering for the patient. The use of an opioid as analgesic monotherapy can lead to poorly controlled pain as well as multiple side effects. Non-opioid adjunctive analgesics, such as antidepressants and antiepileptic drugs (AEDs) often improve both pain control, and side effect prevalence. Levetiracetam is an AED with unique mechanisms of action that may have analgesic properties in various pain syndromes. Seven patients with neoplasms involving neural structures (four invading the brachial plexus, and three the lumbosacral plexus) had severe pain of 8 to 9 out of 10 on a visual analog scale (VAS), despite the use of parenteral opioids and various adjunctive therapies. These patients were treated with oral levetiracetam titrated over days to two weeks, depending on the location of pain, drug response, and tolerance to tapering of opioid analgesics. Opioid and adjunctive analgesic use and VAS scores were recorded periodically. The maximum levetiracetam dose ranged from 500 mg to 1500 mg BID. All patients experienced pain control improvement after the addition of levetiracetam, with VAS scores decreasing from 8-9 out of 10 to 0-3 out of 10 within two to 14 days of therapy initiation. Overall opioid use decreased by at least an estimated 70%, without drug related adverse events. In this small series of patients, levetiracetam effectively and safely improved pain relief in patients with neoplastic plexopathies previously resistant to standard analgesic approaches.