NAME OF DRUG
baclofen

CLASSIFICATION

Muscle relaxant, antispastic

ALTERNATE NAMES

LIORESAL

INDICATIONS

• management of patients with severe spinal cord spasticity who are unresponsive or experience unacceptable side effects from oral baclofen

RECONSTITUTION AND STABILITY

• stable at room temperature, protect from heat
• discard if solution is cloudy, discoloured, or contains particulate matter

COMPATIBILITY

• compatible with normal saline
• incompatible with dextrose solutions
• do not mix with any other drug or infusion solution

ROUTES OF ADMINISTRATION

• Intrathecal only - direct via barbotage over at least 1 minute or via continuous intrathecal infusion

• After a bolus test injection: temperature, pulse, respiratory rate, oxygen saturation and blood pressure must be monitored q30minutes x 2 post injection, then q1h until patient is discharged.  Refer to Patient Care GuidelinesI (Intrathecal Baclofen Test Dose I-095)

Direct intrathecal administration by physician only

DOSAGE

Test dose:

• 25-50 mcg intrathecally by barbotage over at least one minute; if no response, increase by 25 mcg increments every 24 hours until a 4-8 hour clinical response is demonstrated; if no response occurs to a 100 mcg test dose, then no further dosage should be considered
• If adverse reaction occurs to initial 25 mcg test dose, a 10 mcg test dose may be considered

Maintenance dose:

• Double the initial screening dose patient responded to and administer by continuous intrathecal infusion over 24 hours; if initial screening dose lasted greater than 12 hours, then do not double the dose but use the same screening dose administered over 24 hours
• Dosage may be adjusted upward in titrations of 10-30% every 24-48 hours
• Maintenance dosage range: 10-1200 mcg/day (average 300-800 mcg/day)

POTENTIAL HAZARDS OF PARENTERAL ADMINISTRATION

• onset of effect post intrathecal bolus is 1-2 hours with peak onset at 2-4 hours; duration of effect is 4-8 hours
• life-threatening CNS depression, cardiovascular collapse and/or respiratory failure; resuscitative equipment should be readily available for the first dose
• patients receiving concomitant benzodiazepines or opiates are at higher risk of respiratory depression

IMPORTANT IMPLICATIONS

• most common side effects include drowsiness, weakness in the lower extremities, dizziness/lightheadedness, seizures, headache, nausea and vomiting
• avoid abrupt withdrawal as a hyperactive state with rapid and uncontrolled spasms, and increased rigidity may occur; to discontinue, dosage should be tapered slowly over a period of 1-2 weeks

Rev. June 2007