Bupivacaine administered intrathecally versus rectally in the management of intractable rectal cancer pain in palliative care

BACKGROUND Unacceptable adverse effects, contraindications to and/or ineffectiveness of World Health Organization step III "pain ladder" drugs causes needless suffering among a population of cancer patients. Successful management of severe cancer pain may require invasive treatment. However, a patient's refusal of an invasive procedure necessitates that clinicians consider alternative options. OBJECTIVE Intrathecal bupivacaine delivery as a viable treatment of intractable pain is well documented. There are no data on rectal bupivacaine use in cancer patients or in the treatment of cancer tenesmoid pain. This study aims to demonstrate that bupivacaine administered rectally could be a step in between the current treatment options for intractable cancer pain (conventional/conservative analgesia or invasive procedures), and to evaluate the effect of the mode of administration (intrathecal versus rectal) on the bupivacaine plasma concentration. CASES We present two Caucasian, elderly inpatients admitted to hospice due to intractable rectal/tenesmoid pain. The first case is a female with vulvar cancer, and malignant infiltration of the rectum/vagina. Bupivacaine was used intrathecally (0.25-0.5%, 1-2 mL every 6 hours). The second case is a female with ovarian cancer and malignant rectal infiltration. Bupivacaine was adminstered rectally (0.05-0.1%, 100 mL every 4.5-11 hours). METHODS Total bupivacaine plasma concentrations were determined using the high-performance liquid chromatography-ultraviolet method. RESULTS Effective pain control was achieved with intrathecal bupivacaine (0.077-0.154 mg·kg(-1)) and bupivacaine in enema (1.820 mg·kg(-1)). Intrathecal bupivacaine (0.5%, 2 mL) caused a drop in blood pressure; other side effects were absent in both cases. Total plasma bupivacaine concentrations following intrathecal and rectal bupivacaine application did not exceed 317.2 ng·mL(-1) and 235.7 ng·mL(-1), respectively. Bupivacaine elimination was slower after rectal than after intrathecal administration (t½= 5.50 versus 2.02 hours, respectively). LIMITATIONS This study reports two cases only, and there could be inter-patient variation. CONCLUSION Bupivacaine in boluses administered intrathecally (0.25%, 2 mL) provided effective, safe analgesia in advanced cancer patients. Bupivacaine enema (100 mg·100 mL(-1)) was shown to be a valuable option for control of end-of-life tenesmoid cancer pain.