What Are Implantable Drug Pumps?

Question: What Are Implantable Drug Pumps?

Because it’s easiest for both patient and doctor, drugs such as pain medications are generally taken by mouth. But did you know that there are other routes of administration for medications? Examples might include injections into the epidural space, a patch worn on the skin, such as the Fentanyl patch, or an implantable pump that delivers medication directly to a targeted area around the spinal cord.

Answer:

For many people with excruciating spine pain, taking meds by mouth just doesn’t do the job. An implantable drug delivery system (aka, the drug pump) is sometimes used as a last resort to control neuropathic pain and/or spasticity. The drug pump provides a way of delivering the medication directly to your spinal cord, greatly reducing the ">amount of narcotics needed for pain relief. Drug pumps have been around for approximately 30 years, having been used mainly for cancer and post operative pain. More recently, drug pumps have begun to be implanted in patients with chronic back pain.

After a trial to determine if the treatment will be helpful in relieving your pain, and to begin to determine the dosage you will need, the pump is surgically placed in your abdominal area. It is connected to a catheter that is inserted into one of two spaces surrounding the spinal cord. Generally, for chronic back pain patients who do not have cancer, the catheter will be placed in the intrathecal space, located very near the spinal cord, where cerebrospinal fluid flows. Sometimes the catheter is inserted into the epidural space, located just outside the spinal cord, in the vertebral canal. A catheter in the epidural space is usually reserved for patients with cancer pain and, to a lesser extent, for back patients during their trial run.

While doctors seem eager to apply current knowledge about implantable drug pumps to cases of chronic (non-cancer) spine pain, the research as yet does not provide evidence that this treatment delivers the long term relief back patients seek.

The description - drug delivery system - (and related terms) might refer to the drug itself or the device used to deliver the drug. Implantable drug delivery systems are regulated by the Center for Drug Evaluation and Research at the FDA. A drug pump is considered to be a combination product (i.e., it is both a device and a drug), with drug as its primary mode of action.

_{Sources:
Dr. Sudhir Diwan, Director Pain Medicine Fellowship Program and Director of the Division of Pain Medicine at Weil-Cornell Medical College of Cornell University. Telephone Interview. May 2008.}

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