Baclofen acts on the central nervous system to relieve spasms, cramping, and tightness of muscles caused by spasticity in multiple sclerosis. Intrathecal baclofen therapy (ITB) consists of long-term delivery of baclofen to the intrathecal space in the spinal column. It is used in MS for those individuals with severe spasticity whose symptoms are not sufficiently relieved with oral baclofen and other oral medications. Because ITB is administered directly in to the intrathecal space, it provides better spasticity reduction at lower doses than can be achieved with oral medications that, at higher doses, can produce sedation, sleepiness, and imbalance.
Individuals who are considered candidates for intrathecal baclofen are given a test dose via lumbar puncture. Those who respond positively to the test dose can be considered for ongoing ITB therapy.
The SynchroMed® Infusion System (Medtronic) consists of: a small titanium disk, about three inches in diameter and one inch thick, which contains a refillable reservoir for the liquid; a computer chip that regulates the battery-operated pump; and a flexible silicone catheter that serves as the pathway from the pump to the intrathecal space.
Implantation of the pump requires two incisions, one in the lower abdomen to create a pocket for the pump, and another one in the lower back for inserting the catheter that is looped around the torso, inside the body, connecting the pump to the intrathecal space.
The dose of medication delivered by the pump is programmed and subsequently adjusted if necessary by non-invasive radio-telemetry. The pump is refilled every 4 to 12 weeks by injection in a procedure lasting about 20 minutes.
To prevent the baclofen supply from running out, the pump contains a programmable alarm that sounds whenever the reservoir need to be refilled, the battery is low, or the pump is malfunctioning in some way. In the event that the alarm sounds, you should contact your physician immediately.
As with any surgical procedure, the implantation of the pump carries with it the risk of infection and the risks associated with general anesthesia. There is an additional risk of spinal fluid leakage.
Your doctor should check your progress at regular visits, especially during the first few weeks of treatment with this medicine. During this time, the amount of medicine you are using may have to be changed often to meet your individual needs.
Make sure to keep all appointments to refill the pump. If the pump is not refilled on time you may experience return of your muscle tightness and early withdrawal symptoms that might include: itching of the skin; decreased blood pressure; blurred vision*; confusion; dizziness; faintness or lightheadedness when rising from a lying or sitting position; sweating; unusual tiredness or weakness*; burning, crawling, itching, numbness, prickling, "pins and needles" or tingling feelings*; seizures.
Abruptly stopping intrathecal baclofen can result in serious medical problems and in rare cases has been fatal.
Possible Side Effects
Side effects that typically go away as your body adjusts to the medication and do not require medical attention unless they continue for several weeks or are bothersome: drowsiness or unusual tiredness*; increased weakness*; dizziness or lightheadedness; confusion; unusual constipation*; new or unusual bladder symptoms*; trouble sleeping; unusual unsteadiness or clumsiness*.
Unusual side effects that require immediate medical attention: high fever; altered mental status; spasticity than is worse than was experienced prior to starting ITB Therapy; muscle rigidity.
Symptoms of overdose: drowsiness; lightheadedness; sudden onset of blurred or double vision*; shortness of breath or troubled breathing; vomiting; seizures; loss of consciousness; coma.
*Since it may be difficult to distinguish between certain common symptoms of MS and some side effects of baclofen, be sure to consult your health care professional if an abrupt change of this type occurs.