Alternative treatments of breakthrough pain in patients receiving spinal analgesics for cancer pain

Patients who experience a poor response to different systemic opioid trials (oral and intravenous) are candidates for spinal treatment. Breakthrough pain occurring in this group of patients is challenging for physicians. This phenomenon has never been described in this context and the treatment is quite difficult, as patients already demonstrated a poor response to systemic opioids. We report a preliminary experience of alternative methods, including the intrathecal injection of local anesthetic boluses as needed, or alternatively, the use of sublingual ketamine. Twelve consecutive patients with advanced cancer and pain were selected for intrathecal treatment after receiving different trials with systemic opioids. During intrathecal therapy, pain flares not responding to high doses of intravenous morphine were treated with intrathecal boluses of local anesthetics titrated to achieve the best balance between analgesia and adverse effects, or with sublingual ketamine (25 mg), according to their preference. Pain and symptoms were recorded for each episode of breakthrough pain during hospital admission. Effective pain control was achieved in all the episodes treated within 10 minutes with either method, without relevant complications. A mean volume of 0.6 mL of levobupivacaine (LB) 0.25% (1.5 mg) was effective within a few minutes and was well tolerated in patients receiving a continuous intrathecal infusion of a combination of morphine and LB in different doses. Similarly, ketamine in doses of 25 mg sublingually was effective and relatively well tolerated. Despite the difficult clinical situation of these patients, these approaches controlled almost all breakthrough pain events previously unresponsive to relatively high doses of intravenous opioids. These intensive treatments should be reserved for a very selected population and initiated in an appropriate selling with frequent monitoring facilities and skilled nursing.