Long-term epidural ketamine, morphine and bupivacaine attenuate reflex sympathetic dystrophy neuralgia

There is considerable evidence that NMDA receptor antagonists can abolish nociceptor hypersensitivity in animals. In the present case report, two patients with reflex sympathetic dystrophy were treated with ketamine, a NMDA antagonist, morphine and bupivacaine.

Two patients were referred suffering from severe pain, allodynia, hyperaesthesia, swelling and disability over their right lower legs, diagnosed as reflex sympathetic dystrophy. They had received conventional treatments with non-steroid anti-inflammatory drugs (NSAIDs), steroids, anticonvulsant, antidepressant, epidural lidocaine sympathetectomy and rehabilitation which failed to provide satisfactory pain relief. We administered subanalgesic doses of ketamine (7.5 mg), morphine (0.75 mg) and 6 ml bupivacaine 0.1% via a lumbar epidural catheter three times per day. After several courses of treatment over three and six months, satisfactory pain relief was achieved in each patient. Both are now able to walk with slight weight bearing with the assistance of crutch. The treatment is continuing with further improvement of symptoms and signs.

Epidural coadministration of low doses of morphine, ketamine and bupivacaine provided effective pain relief in two patients. This suggests synergy from this combination that provides an alternative treatment for reflex sympathetic dystrophy.