Many medications that are normally given orally or intravenously can be delivered directly into the spinal canal. The advantage of this delivery is that a much smaller dosages of medication can be used, thereby minimizing many side effects associated with other oral or intravenous use.
Typically, the intraspinal administration is 300 times more effective than the oral dose. Morphine (and other opioids or narcotics) interacts with opioid receptors in the spinal cord to decrease pain impulses to the brain, thereby decreasing the brain's perception of painful conditions. While developed for cancer pain, the intraspinal use of this medication has proven very effective in chronic benign (non-cancer) pain as well.
Intraspinal delivery may allow the patient to significantly decrease the amount of oral medications ingested, thereby decreasing side effects. Because the effectiveness of intraspinal morphine is many-times the effectiveness of oral morphine, the patient's pain relief may allow resumption of a much more active lifestyle. Baclofen is a medication that also works on the spine, interacting with GABA receptors to decrease spasticity. As with morphine, the intraspinal administration is much more effective than oral ingestion, thereby decreasing side effects and improving muscle relaxation.
Intraspinal baclofen therapy is used for spasticity that occurs from injuries to the brain or spine. The therapy has proven effective for children with cerebral palsy or traumatic brain injuries and for adults who have suffered cerebrovascular accidents (strokes) or spinal injuries. Although morphine and baclofen are the most commonly used intraspinal medications, clinical circumstances may require the use of other medications, either alone or in combination.
These medications include the opioids hydromorphone and fentanyl as well as clonidine, bupivicaine and zinconotide. Prior to the implantation of the pump and catheter, a trial procedure is performed which demonstrates the effectiveness of the medication for the particular patient. The implantation requires a surgical operation and an anesthetic.