The aim of this study is determine whether or not the antiepileptic drug Levetiracetam is an effective treatment of the postmastectomy pain syndrome.

This study is a randomised, placebocontrolled, doubleblind study on the effect of the antiepileptic drug, levetiracetam, in patients suffering from PMPS. The treatment periods are 1 month each and the periods are separated by a 1-week washout period. The daily dose of levetiracetam is increased over a 2-week period to 3.000 mg/day. The primary effect variable is pain relief by the use of numeric rating scale. Secondary parameters are daily registration of pain performed by the patients during the treatment periods and the amount of escape medicine used (paracetamol and tramadol). Sensory testing is performed at baseline and after each treatment period.

Inclusion Criteria:

• Symptoms characteristic for postmastectomy pain syndrome with a duration of more than 3 months and at least 6 months after the operation.
• Neuropathic pain diagnose confirmed by abnormities in the neurological investigation and/or psychophysical sensory testing
• Average (1 week) pain score minimum 4 on a 11 points numerical rating scale for total pain.
• Pain present minimum 4 out of 7 days.
• Fertile women must use anticonception.

Exclusion Criteria:

• Verified og suspected other reason than mastectomy/lumpectomy for the pain.
• Known allergic effects to levetiracetam.
• Known sideeffects to treatment with levetiracetam.
• Pregnancy or breast-feeding.
• Severe disease (terminal cancer, heart failure, kidney insufficiency, severe respiratory problems)
• Compliance problems