Dosing & Uses
Dosage Forms & Strengths
tablet
- 5mg (generic)
- 10mg (generic)
- 20mg (generic)
oral solution
- 5mg/5mL (Ozobax)
intrathecal solution, preservative free
- 500mcg/mL (generic, Lioresal, Gablofen)
- 1000mcg/mL (generic, Lioresal, Gablofen)
- 2000mcg/mL (generic, Lioresal, Gablofen)
Spasticity
Indicated for spasticity resulting from multiple sclerosis, particularly for the relief of flexor spasms and concomitant pain, clonus, and muscular rigidity
Oral
- May also be of some value in patients with spinal cord injuries and other spinal cord diseases
- Initiate with a low dosage, preferably in divided doses, PO
-
Following suggested gradual increase dosage regimen based on clinical response and tolerability
- 5 mg PO TID initially; after 3 days, may increase by 5 mg/dose q3days up to 20 mg PO TID
- If necessary, may increase to a maximum of 80 mg/day (20 mg QID)
Intrathecal
-
Screening phase
- Test bolus: 50 mcg intrathecal by barbotage over <1 minute; if inadequate response within 8 hr, 75 mcg 24 hr later; if still inadequate, 100 mcg 24 hr 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)
Dosage Modifications
Renal impairment
- Because baclofen is primarily excreted unchanged through the kidneys, use caution and consider reducing the dosage if necessary
Orphan Indications
Treatment of dystonia
Treatment of spasticity associated with cerebral palsy
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
Dosing Considerations
Lioresal and Gablofen are administered chronically by the Medtronic SynchroMed II pump or other pumps labeled for IT use with these products
Limitation of use
- Not indicated for skeletal muscle spasm resulting from rheumatic disorders
Dosage Forms & Strengths
tablet
- 5mg (generic)
- 10mg (generic)
- 20mg (generic)
oral solution
- 5mg/5mL (Ozobax)
intrathecal solution, preservative free
- 500mcg/mL (generic, Lioresal, Gablofen)
- 1000mcg/mL (generic, Lioresal, Gablofen)
- 2000mcg/mL (generic, Lioresal, Gablofen)
Spasticity
Indicated for spasticity resulting from multiple sclerosis, particularly for the relief of flexor spasms and concomitant pain, clonus, and muscular rigidity
Oral
May also be of some value in patients with spinal cord injuries and other spinal cord diseases
<12 years: Safety and efficacy not established
≥12 years: Initiate with a low dosage, preferably in divided doses, PO
Following suggested gradual increase dosage regimen based on clinical response and tolerability
- 5 mg PO TID initially; after 3 days, may increase by 5 mg/dose q3days up to 20 mg PO TID
- If necessary, may increase to a maximum of 80 mg/day (20 mg QID)
Intrathecal
-
Screening phase
- Test bolus: 50 mcg intrathecal by barbotage over 1 minute; if inadequate response within 8 hr, 75 mcg 24 hr later; if still inadequate, 100 mcg 24 hr 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 hr, 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
Dosage Modifications
Renal impairment
- Because baclofen is primarily excreted unchanged through the kidneys, use caution and consider reducing the dosage if necessary
Dosing Considerations
Lioresal and Gablofen are administered chronically by the Medtronic SynchroMed II pump or other pumps labeled for IT use with these products
Limitation of use
- Not indicated for skeletal muscle spasm resulting from rheumatic disorders
Spasticity With Cerebral Palsy (Orphan)
Intractable spasticity
Orphan indication sponsor
- Osmotica Pharmaceutical Corp; 1205 Culbreth Drive, Suite 200; Wilmington, NC 28405
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Adverse Effects
>10%
Oral solution/tablets
- Drowsiness (10-63%)
- Dizziness (5-15%)
- Weakness (5-15%)
- Nausea (4-12%)
- Confusion (1-11%)
- Intrathecal H4
- Hypotonia (2.4-34.7%)
- Somnolence (5.7-20.9%)
1-10%
Oral solution/tablets
- Hypotension (0-9%)
- Headache (4-8%)
- Insomnia (2-7%)
- Constipation (2-6%)
- Urinary frequency (2-6%)
- Fatigue (2-4%)
Intrathecal
- Convulsion (0.5-10%)
- Urinary retention (0.9-8%)
- Dizziness (1.7-8%)
- Paresthesia (2.1-6.7%)
- Nausea and vomiting (1.4-7.3%)
- Headache (1.6-10.7%)
- Constipation (0.2-5.1%)
- Pruritus (4%)
- Hypotension (0.2-4%)
- Pain (0.6-4%)
- Accidental injury (0.2-3.5%)
- Speech disorder (0.2-3.5%)
- Dry mouth (0.2-3.3%)
- Peripheral edema (2.3-3.3%)
- Death (0.2-3%)
- Increased salivation (2.6-2.7%)
- Ambylopia (0.2-2.3%)
- Diarrhea (0.5-2.3%)
- Confusion (0.5-2.3%)
- Hypoventilation (0.2-2.1%)
- Back pain (0.9-2%)
- Urinary incontinence (0.8-2%)
- Pneumonia (0.2-2%)
- Urinary retention (0.7-1.9%)
- Impotence (0.2-1.6%)
- Insomnia (0.4-1.6%)
- Depression (1.6%)
- Thinking abnormal (0.5-1.3%)
- Agitation (0.5-1.3%)
- Asthenia (0.7-1.4%)
- Tremor (1.3%)
- Coma (0.9-1.2%)
- Urticaria (0.2-1.2%)
- Dyspnea (0.3-1.2%)
<1%
Intrathecal
- Anorexia (0.4-0.9%)
- Diplopia (0.4-0.9%)
- Dysautonomia (0.2-0.9%)
- Anxiety (0.2-0.9%)
- Urinary frequency (0.6-0.9%)
- Fever (0.2-0.7%)
- Hypertension (0.2-0.6%)
- Hallucinations (0.3-0.5%)
Frequency Not Defined
Oral solution/tablets
- Neuropsychiatric: Euphoria, excitement, depression, hallucinations, paresthesia, muscle pain, tinnitus, slurred speech, coordination disorder, tremor, rigidity, dystonia, ataxia, blurred vision, nystagmus, strabismus, miosis, mydriasis, diplopia, dysarthria, epileptic seizure
- Cardiovascular: dyspnea, palpitation, chest pain, syncope Gastrointestinal: dry mouth, anorexia, taste disorder, abdominal pain, vomiting, diarrhea, and positive test for occult blood in stool
- Genitourinary: Enuresis, urinary retention, dysuria, impotence, inability to ejaculate, nocturia, hematuria
- Other: Rash, pruritus, ankle edema, excessive perspiration, weight gain, nasal congestion
Postmarketing Reports
Onset of scoliosis or worsening of a pre-existing scoliosis
Sexual dysfunction in men and women, including decreased libido and orgasm dysfunction
Erectile dysfunction in men following baclofen withdrawal
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
Intrathecal use: IV, IM, SC or epidural administration
Cautions
Use with caution in patients who have had a stroke; baclofen has not significantly benefited patients with stroke; patients have also shown poor tolerability to the drug
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 has resulted in adverse reactions that include hallucinations, seizures, high fever, altered mental status, exaggerated rebound spasticity, and muscle rigidity, that in rare cases has advanced to rhabdomyolysis, multiple organ-system failure, and death
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 with caution in patients with a history of autonomic dysreflexia; presence of nociceptive stimuli or abrupt withdrawal may cause autonomic dysreflexia episode
Possible exacerbation of psychotic disorders, schizophrenia or confusional state
Neonatal withdrawal symptoms can occur; gradually reduce the dosage and discontinue oral baclofen before delivery
Patients should avoid the operation of automobiles or other dangerous machinery until they know how the drug affects them; advise patients that the central nervous system effects may be additive to those of alcohol and other CNS depressants
Use with caution in patients where spasticity is utilized to sustain upright posture and balance in locomotion or whenever spasticity is utilized to obtain increased function
Intrathecal administration
- Intrathecal used with implanted pump
- Not for injection into pump catheter access port, as this may cause a life-threatening overdose
- Delivery of more drug volume than the programmed rate (over infusion) can result in unexpected overdose, or withdrawal caused by early emptying of pump reservoir; refer to manufacturer's pump manual and instructions for refilling the reservoir
- Potential for contamination due to non-sterile external surface of prefilled syringe; use of baclofen prefilled syringe in an aseptic setting (eg, 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
- 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
Drug interaction overview
- Baclofen may cause CNS depression, including drowsiness and sedation, which may be additive when used concomitantly with other CNS depressants or alcohol
Pregnancy & Lactation
Pregnancy
There are no adequate data on the developmental risk associated with the use in pregnant women
Oral administration of baclofen to pregnant rats resulted in an increased incidence of fetal structural abnormalities at a dose which was also associated with maternal toxicity
Clinical considerations
- May increase the risk of late-onset neonatal withdrawal symptoms
Animal data
- Baclofen given orally has been shown to increase the incidence of omphaloceles (ventral hernias) in fetuses of rats given ~13 times on a mg/kg basis, or 3 times on a mg/m2 basis, the maximum oral dose recommended for human use; this dose also caused reductions in food intake and weight gain in the dams
- This abnormality was not seen in mice or rabbits
Lactation
At recommended oral doses, baclofen is present in human milk
There are no human data on the effects of baclofen on milk production
There are no adequate data on the effects of baclofen on the breastfed infant
Withdrawal symptoms can occur in breastfed infants when maternal administration is stopped, or when breastfeeding is stopped
Consider developmental and health benefits of breastfeeding along with the mother’s clinical need and any potential adverse effects on the breastfed infant or from the underlying maternal condition
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
Mechanism of Action
Precise mechanism of action of baclofen is not fully understood
Baclofen inhibits both monosynaptic and polysynaptic reflexes at the spinal level, possibly by decreasing excitatory neurotransmitter release from afferent terminals, although actions at supraspinal sites may also occur and contribute to its clinical effect
It is a structural analog of the inhibitory neurotransmitter gamma aminobutyric acid (GABA), and may exert its effects by stimulation of the GABAB receptor subtype
Absorption
Onset: 6-8 hr (IT)
Duration: 4-8 hr
Peak plasma time: 28-48 hr (IT); 0.75 hr (PO)
Elimination
Half-life: 1.51 hr (IT); 5.7 hr (PO)
Clearance: 30 mL/hr (IT)
Excretion: Urine and feces (85%; unchanged)
Administration
Oral Administration
Take with or without food
Discontinuing: slowly reduce dose and avoid abrupt withdrawal to minimize risk of serious adverse events (eg, hallucinations, seizures, high fever, altered mental status, exaggerated rebound spasticity, and muscle rigidity, rhabdomyolysis, multiple-organ failure, death)
Intrathecal Preparation
Inspect ampules for particulate matter and discoloration before administration, whenever solution and container permit
Screening use
- The 1 mL screening ampule only (50 mcg/mL) for bolus injection into the subarachnoid space
- For a 50 mcg bolus dose, use 1 mL of the screening ampule
- Use 1.5 mL of 50 mcg/mL baclofen injection for a 75 mcg bolus dose
- For the maximum screening dose of 100 mcg, use 2 mL of 50 mcg/mL baclofen injection (2 screening ampules)
Maintenance
- Concentrations other than 500 mcg/mL or 2000 mcg/mL, drug must be diluted
- Dilute with sterile preservative free NaCl
Intrathecal Administration
Often administered in a continuous infusion mode immediately following implant
Patients implanted with programmable pumps who have achieved relatively satisfactory control on continuous infusion, further benefit may be attained using more complex schedules of drug delivery (eg, patients who have increased spasms at night may require a 20% increase in their hourly infusion rate; changes in flow rate should be programmed to start 2 hr before the time of desired clinical effect)
Storage
Oral solution: Refrigerate at 2-8ºC (36-46ºF); dispense in a tight, light-resistant container with a child-resistant closure
Tablet: Store at 2-25ºC (68-77ºF)
Injection: Does not require refrigeration; do not store above 86ºF (30ºC); do not freeze; do not heat sterilize
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Formulary
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