Dosing and uses of Lioresal, Gablofen (baclofen)
Adult dosage forms and strengths
tablet
- 10mg
- 20mg
intrathecal solution
- 50mcg/mL
- 500mcg/mL
intrathecal solution, preservative free
- 500mcg/mL
- 1000mcg/mL
- 2000mcg/mL
Spasticity
5 mg PO q8hr; may increase by 5 mg/dose q3Days to maximum 80 mg/day
Spasticity (Intrathecal Administration)
Screening phase
- Test bolus: 50 mcg intrathecal by barbotage over <1 minute; if inadequate response within 8 hours, 75 mcg 24 hours later; if still inadequate, 100 mcg 24 hours later
- Patients who do not respond to a 100 mcg intrathecal bolus should not be considered candidates for an implanted pump for chronic infusion
Titration (after initial 24 hr)
- Initial implant dose: 2 times screening dose that gave positive effect (or screening dose if effect lasted >8 hr) administer over 24-hour period
- Spasticity of spinal cord origin: Increase by 10-30% q24hr until desired clinical effect
- Spasticity of cerebral origin: Increase by 5-15% q24hr until desired clinical effect
Maintenance
- Spasticity of spinal cord origin: Increase by 10-40% or decrease by 10-20% during periodic pump refills; usual range 300-800 mcg/day (not to exceed 1000 mcg/day)
- Spasticity of cerebral origin: Increase by 5-20% or decrease by 10-20% during periodic pump refills; usual range 90-700 mcg/day (not to exceed 1000 mcg/day)
Dosing considerations
- Lioresal and Gablofen are administered chronically by the Medtronic SynchroMed II pump or other pumps labeled for IT use with these products
Dosage modifications
Renal failure: Dose reduction may be necessary
Orphan Indications
Treatment of dystonia
Treatment of spasticity associated with cerebral palsy
Treatment of intractable spasticity associated with spinal cord injury or multiple sclerosis
Trigeminal neuralgia
Gablofen: Treatment of complex regional pain syndrome
Sponsors
- Medtronic Neurological: 710 Medtronic Parkway NE; Minneapolis, MN 55432-5604
- Osmotica Pharmaceutical Corp: 1205 Culbreth Drive, Suite 200; Wilmington, NC 28405
- Mallinckrodt, Inc; 675 McDonnell Blvd; St. Louis, Missouri 63134
Pediatric dosage forms and strengths
tablet
- 10mg
- 20mg
intrathecal solution
- 50mcg/mL
- 500mcg/mL
intrathecal solution, preservative free
- 500mcg/mL
- 1000mcg/mL
- 2000mcg/mL
Spasticity
<2 years: 10-15 mg PO divided q8hr; increase dose q3Days by 5-15 mg/day; 40 mg/day maximum
Age 2-8 years: 10-15 mg/day PO divided q8hr; increase dose q3Days by 5-15 mg/day; 40 mg/day maximum
>8 years: 10-15 mg/day PO divided q8hr; increase dose q3Days by 5-15 mg/day; 60 mg/day maximum
Spasticity (Intrathecal Administration)
Screening phase
- Test bolus: 50 mcg intrathecal by barbotage over 1 minute; if inadequate response within 8 hours, 75 mcg 24 hours later; if still inadequate, 100 mcg 24 hours later
- May start with 25 mcg dose for small patients
- Patients who do not respond to a 100 mcg intrathecal bolus should not be considered candidates for an implanted pump for chronic infusion
Titration (after initial 24 hr)
- Initial implant dose: 2 times screening dose that gave positive effect (or screening dose if effect lasted >8 hr) administer over 24 hr period
- After the first 24 hours, the daily dose should be increased slowly by 5-15% only once q24hr, until desired clinical effect is achieved
Maintenance
- Maintenance dose: Same as adult with spasticity of cerebral origin (average dose usually lower than adult)
- Increase by 5-20% or decrease by 10-20% during periodic pump refills
- Average daily dose for patients <12 years was 274 mcg/day, with a range of 24-1199 mcg/day
Dosing considerations
- <4 years: Safety and efficacy not established
- Lioresal and Gablofen are administered chronically by the Medtronic SynchroMed II pump or other pumps labeled for IT use with these products
Spasticity With Cerebral Palsy (Orphan)
Intractable spasticity
Orphan indication sponsor
- Osmotica Pharmaceutical Corp; 1205 Culbreth Drive, Suite 200; Wilmington, NC 28405
Lioresal, Gablofen (baclofen) adverse (side) effects
>10%
Drowsiness, transient (10-63%)
Dizziness (5-15%)
Nausea (4-12%)
Confusion (1-11%)
1-10%
Headache (4-8%)
Insomnia (2-7%)
Constipation (2-6%)
Urinary frequency (2-6%)
Fatigue (2-4%)
<1%
Abdominal pain
Ankle edema
Anorexia
Ataxia
Blurred vision
Chest pain
Coordination disorder
Depression
Diarrhea
Dry mouth
Diplopia
Dysarthria
Dyspnea
Dystonia
Enuresis
Euphoria
Excitement
Hallucinations
Hematuria
Hypotension
Impotence
Miosis
Muscle pain
Mydriasis
Nasal congestion
Nocturia
Nystagmus
Palpitation
Paresthesia
Excessive perspiration
Pruritus
Rash
Rigidity
Seizure
Strabismus
Slurred speech
Syncope
Tinnitus
Tremor
Urinary retention
Vomiting
Weight gain
Warnings
Black box warnings
Abrupt discontinuation, of intrathecal baclofen, has resulted in high fever, altered mental status, exaggerated rebound spasticity, and muscle rigidity that, in rare cases, advances to rhabdomyolysis, multiple organ system failure, and death
Prevention of abrupt discontinuation requires careful attention to programming and monitoring of infusion system, refill scheduling and procedures, and pump alarms; advice patients and caregivers of importance of keeping scheduled refill visits and educate on the early symptoms of baclofen withdrawal; give special attention to patients at apparent risk (eg, spinal cord injuries at T-6 or above, communication difficulties, history of withdrawal symptoms from oral or intrathecal baclofen)
Contraindications
Hypersensitivity
Intravenous, intramuscular, subcutaneous or epidural administration
Cautions
May cause drowsiness/dizziness
Not indicated for spasm with rheumatic disease, stroke, Parkinson
May take with food to avoid stomach upset
Not significantly beneficial for patient with stroke
Use with caution in seizure disorders and renal impairment
Abrupt drug discontinuation may result in hallucinations and seizures
May cause acute urinary retention that may be related to underlying disease; use caution in patients with urinary obstruction
Animal studies have shown increased incidence in ovarian cysts; effect in humans inconclusive
Use with caution in patients with decreased GI motility, peptic ulcer disease, and/or gastrointestinal obstructive disorders
Use caution in respiratory disease and in the elderly
Potential toxic dose if <6 years: 5 mg/kg (PO)
Monitor: EEg
Intrathecal administration
- Intrathecal used with implanted pump
- Not for injection into pump catheter access port, as this may cause a life-threatening overdose
- Potential for contamination due to non-sterile external surface of prefilled syringe; use of baclofen prefilled syringe in an aseptic setting (e.g., operating room) to fill sterile intrathecal pumps prior to implantation in patients not recommended, unless external surface of prefilled syringe is treated to ensure sterility
- Potentially life-threatening CNS depression, cardiovascular collapse, and/or respiratory failure
- Resuscitative equipment and trained staff must be available during screening, dose titration, and refills
- Overdose may cause drowsiness, lightheadedness, dizziness, somnolence, respiratory depression, seizures, rostral progression of hypotonia and loss of consciousness progressing to coma
- Possible exacerbation of psychotic disorders, schizophrenia or confusional states may occur
- Intrathecal mass: Cases of intrathecal mass at the tip of the implanted catheter have been reported, most of them involving pharmacy-compounded analgesic admixtures; the most frequent symptoms associated with intrathecal mass include decreased therapeutic response (worsening spasticity, return of spasticity when previously well controlled, withdrawal symptoms, poor response to escalating doses, or frequent or large dosage increases), pain, and neurologic deficit/dysfunction
- Inadvertent injection into the SC tissue can occur if the intrathecal reservoir refill septum is not properly accessed; SC injection may result in symptoms of a systemic overdose or early depletion of the reservoir
Pregnancy and lactation
Pregnancy category: C
Lactation: Enters breast milk in small amounts; not recommended
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Lioresal, Gablofen (baclofen)
Mechanism of action
Inhibits synaptic transmission through spinal reflex arcs, via hyperpolarization of primary afferent fiber terminals, which may result in muscle spasticity
Absorption
Onset: 3-4 days
Duration: 4-8 hr
Peak plasma time: 2-3 hr
Peak plasma concentration: 500-600 ng/mL
Peak effect: 5-10 days
Distribution
Protein bound: 30%
Metabolism
Metabolized by liver (15%), mostly by deamination
Elimination
Half-life: 2.5-4 hr
Excretion: Urine and feces (85%; unchanged)
