USE OF INTRATHECAL BACLOFEN IN TREATMENT OF SPASTICITY

USE OF INTRATHECAL BACLOFEN IN TREATMENT OF SPASTICITY BY: NURUL ISLAH BT MUZAKIR, PRP PRECEPTORS: MR LIM YONG YAN

OUTLINE O INTRODUCTION O INDICATIONS FOR INTRATHECAL O O O O INJECTION INTRATHECAL BACLOFEN PUMP SYSTEM LIORESAL DOSE SIDE EFFECTS MONITORING POSSIBLE COMPLICATIONS REFERENCES

INTRODUCTION O Intrathecal injection is an injection into the spinal canal (intrathecal space surrounding the spinal cord)

INDICATIONS O Local (spinal) anaesthesia: pethidine, ketamine O Chemotherapy: methotrexate, cytarabine O Pain management – palliative care: morphine O Spasticity: baclofen O The drug needs to be given intrathecally to avoid the blood brain barrier.

INTRATHECAL BACLOFEN (ITB) O Baclofen : GABA agonist, muscle relaxant O Used in the treatment of the severe pain and disability secondary to spasticity (occurs in spinal cord injury, traumatic brain injury, stroke, cerebral palsy) O Indicated for patients unresponsive to oral meds or with intolerable CNS side effects with effective oral doses (5 mg tds, max 80 mg/day). O Delivered directly to intrathecal space.

O The oral baclofen delivered throughout the body, only a small portion goes to the spinal fluid where it is needed to work. O An intrathecal delivery system, which provides the baclofen right to the target site in the spinal cord, is an effective way to deliver the medicine.

ITB PUMP SYSTEM

ITB pump system O Consists of a catheter (a small, flexible tube) and a pump (a round metal disc, about one inch thick and three inches in diameter). O Surgically placed under the skin of the abdomen near the waistline. O Stores and releases prescribed amounts of medicine through the catheter. O Refilled by inserting a needle through the skin into a filling port in the center of the pump.

O With a programmable pump, a tiny motor moves the medicine from the pump reservoir through the catheter. Using an external programmer, the dose, rate, and timing of the medicine can be adjusted. O After the implantation procedure, patient will stay in the hospital a few days so their recovery can be closely monitored. O Patient must return to hospital for pump refills and medicine adjustments, typically every 2 -3 months. The pump is taken out and replaced at the end of the battery's life span, which is usually 5 -7 years.

ITB pump system

ITB - LIORESAL® O By Novartis Pharma O Strengths: 0. 5, 2 mg/m. L O Preservative-free O Stable for 90 days O Half-life: 1. 5 hrs O Typical dose: 1/100 of oral dose

ITB DOSE in SPASTICITY – TEST DOSE Lioresal® Package Insert Test dose: bolus 50 mcg (1 m. L) over ≥ 1 minute. If response observed 4 -8 hrs after initial test dose is LESS than desired, administer a second dose of 75 mcg (1. 5 m. L) 24 hrs after the first test dose If response still inadequate (in 4 -8 hrs), administer a final test dose of 100 mcg (2 m. L) 24 hrs after second test dose Prior to pump implantation, pts MUST shows positive clincal response to the bolus dose. Pts not responding to test dose of 100 mcg should not be considered for implanted pump (chronic ITB therapy).

ITB DOSE in SPASTICITY – MAINTENANCE DOSE (INITIAL DOSE) Lioresal® Package Insert If duration of positive response with test dose ≤ 8 hrs, initial daily dose is TWICE the test dose, given over a 24 -hr period. If duration of positive response with test dose >8 hrs, initial daily dose is the SAME as the test dose, given over a 24 -hr period.

ITB DOSE in SPASTICITY – MAINTENANCE DOSE (DOSE TITRATION) Lioresal® Package Insert Spasticity of spinal cord origin Spasticity of cerebral origin After the first 24 hrs, ↑dose by 10 -30% increments once every 24 hrs until desired clinical effect is achieved After the first 24 hrs, ↑dose by 5 -15% increments once every 24 hrs until desired clinical effect is achieved during periodic pump refill ↑ daily dose by 10 -40% ↑ daily dose by 5 -20% if patient experience side effect ↓ dose by 10 -20% Maintenance dosage in most patients 300 -800 mcg / day 90 -703 mcg/day range: 12 -2003 mcg/day range: 22 -1400 mcg/day

ITB - SIDE EFFECTS O Drowsiness O Dizziness O Blurred vision O Slurred speech O Nausea O Confusion

ITB - CONTRAINDICATIONS O Severely impaired renal function O Pregnancy / Lactation O Hx of hypersensitivity to baclofen O Hx of non-compliance to regimen or follow -up

ITB - MONITORING Therapeutic (Physical Findings) O Monitor patient for evidence of a therapeutic response (significant decrease in muscle tone, and/or frequency, and/or severity of spasm) for the first 4 -8 hours following the initial screening dose; and for 4 -8 hours following any subsequent screening doses and the dose titration period immediately following implantation of the pump.

ITB - MONITORING Toxic (Physical Findings) 1) Assess patient for any new neurological signs or symptoms (ie, worsening spasticity, return of spasticity, withdrawal symptoms, poor response to escalating doses, frequent or large dosage increases, pain, neurological deficit/dysfunction) suggestive of an intrathecal mass at the tip of the implanted catheter [107]. O 2) Monitor for signs and symptoms of overdose (ie, drowsiness, dizziness, light-headedness, somnolence, respiratory depression, seizures, rostral progression of hypotonia, and loss of consciousness progressing to coma) during initial screening, dosetitration, during reintroduction of baclofen after a period of interruption in therapy [107].

O 3) Monitor for signs and symptoms of baclofen withdrawal (ie, altered mental status, increased spasticity and muscle rigidity, high fever, pruritus, hypotension, paresthesias), especially in patients at risk, including spinal cord injuries at T-6 or above, communication difficulties, history of withdrawal symptoms O 4) Monitor patient response during the initial phases of pump use and on each occasion when adjustments are made to the dosing rate of the pump, or the concentration in the reservoir, or refilling or manipulation of the reservoir O 5) Monitor programming of the infusion system, refill scheduling and procedures, and pump alarms to prevent abrupt discontinuation of intrathecal baclofen

ITB – POTENTIAL PUMP COMPLICATIONS O Catheter kinking O Disconnection O Dislodgement or pump failure O Programme error O Overfill or incorrect refill

REFERENCES O Mc. Kinley, W. (n. d. ). Intrathecal baclofen pump and other management strategies for spasticity. O The British Pain Society. (2008). Intrathecal drug delivery for the management of pain and spasticity in adults; recommendations for best clinical practice. Retrieved April 11, 2012, from http: //www. britishpainsociety. org O The Cleveland Clinic. (2011). Intrathecal Baclofen Therapy (for MS). Retrieved April 11, 2012, from http: //myclevelandclinic. org

REFERENCES O Lexi-comp Online: Lexi-Drugs O AHFS Essentials O Lioresal® Package Insert O Micromedex O Pub. Med Database

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