Current Developments in Intraspinal Agents for Cancer and Noncancer Pain

Abstract

Since the late 1980s, intrathecal (IT) analgesic therapy has improved, and implantable IT drug delivery devices have become increasingly sophisticated. Physicians and patients now have myriad more options for agents and their combination, as well as for refining their delivery. As recently as 2007, The Polyanalgesic Consensus Conference of expert panelists updated its algorithm for drug selection in IT polyanalgesia. We review this algorithm and the emerging therapy included. This article provides an update on newly approved as well as emerging IT agents and the advances in technology for their delivery.

MEMS: Enabled Drug Delivery Systems

“…The pump is currently in clinical trials to assess the pressure sensor. [ 77 ] In most of the current drug delivery devices, failure is determined only when the patient has shown physical side effects. …”

“…Olive, NJ), utilizes a positive pressure gas expansion actuation design with battery powered valves for fl ow regulation ( Figure 28 ). [ 77 ] The device is intended for chronic pain management and delivers morphine into intrathecal space with a fl ow rate of up to 28 mL per day [ 103 ] (overall 97.5% dose accuracy). The 20 mL fi xed-volume reservoir is refi llable.…”

Neuraxial Agents

“…Smalldiameter A-delta and C fibers primarily transmit nociceptive information. 13 Second-order neurons in the dorsal horn possess a wide variety of neurotransmitter receptors. The excitatory amino acid, glutamate, is also present within small-diameter primary afferents and can be released by noxious stimulation, resulting in the activation of second-order neurons in the dorsal horn of the spinal cord.…”

“…The duration of sensory blockade was prolonged in the group receiving midazolam by over 25 minutes without increasing motor blockade. 13 Prochazka and associates 81 injected doses of 0.02 to 0.06 mg/kg into 14 patients with 10 administrations or more and reported that none of them displayed any clinical signs of neurotoxicity, such as bladder or bowel dysfunction, motor or sensory deficits, or new neuropathic pain. 79 Other studies have found intrathecal midazolam to be effective in treating chronic mechanical low back pain, musculoskeletal pain, and neurogenic pain.…”

“…13 At present, adenosine is considered investigational or only for use in palliative care of terminal patients without further options and full consent of the patient. To date, all human studies assessing neuraxial adenosine have been in either the perioperative setting or experimental pain models.…”