Baclofen 40mg/20ml Inj, 20ml
WARNING: Unsafe side effects have happened when this drug was stopped all of a sudden. Some of these side effects have been high fever, mental changes, more spasms, and muscle stiffness. Rarely, these side effects have led to very bad muscle problems, organ problems, and death. Avoid stopping this drug all of a sudden without talking with your doctor. Be sure you get your pump refilled on time and you know about the pump alarms and what to do if the pump alarm goes off. Tell your doctor if you have ever had signs of withdrawal while getting baclofen tablets or shot. Call your doctor right away if you have signs of withdrawal.Read the package insert for more details. @ COMMON USES: It is used to treat spasms in patients with MS (multiple sclerosis) or spinal cord problems.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Antispasticity agent
Pharmacologic Class
Centrally acting skeletal muscle relaxant; GABA-B receptor agonist
Pregnancy Category
Category C
FDA Approved
Mar 1992
DEA Schedule
Not Controlled
Overview
What is this medicine?
Baclofen injection is a medicine delivered directly into the fluid around your spinal cord using a special pump. It helps to reduce severe muscle stiffness and spasms (spasticity) that can happen with conditions like multiple sclerosis or spinal cord injury. It works by calming overactive nerves in your spinal cord.
How to Use This Medicine
To use this medication correctly, follow your doctor's instructions and carefully read all accompanying information. Adhere to the provided guidelines closely. This medication is administered via injection into the spine.
For storage and disposal, consult with your doctor, nurse, or pharmacist to determine the best approach if you need to keep this medication at home.
If you miss a scheduled dose, contact your doctor promptly to receive guidance on the appropriate course of action.
For storage and disposal, consult with your doctor, nurse, or pharmacist to determine the best approach if you need to keep this medication at home.
If you miss a scheduled dose, contact your doctor promptly to receive guidance on the appropriate course of action.
Lifestyle & Tips
- Always keep your pump refill appointments to prevent the pump from running dry, which can lead to dangerous withdrawal symptoms.
- Carry an identification card stating that you have an implanted baclofen pump.
- Avoid abrupt discontinuation of the medication, as this can cause severe and life-threatening withdrawal symptoms.
- Be aware of the symptoms of overdose and withdrawal and seek immediate medical attention if they occur.
- Avoid activities requiring mental alertness (e.g., driving, operating machinery) until you know how the medication affects you, especially during dose adjustments.
- Inform all healthcare providers that you have an intrathecal baclofen pump.
Available Forms & Alternatives
Available Strengths:
- Baclofen 10mg Tablets
- Baclofen 20mg Tablets
- Baclofen 40mg/20ml Inj, 20ml
- Baclofen 5mg Tablets
- Baclofen 20mg/20ml Inj 20ml
- Baclofen 10mg/20 Inj, 20ml
- Baclofen 5mg/5ml Solution
- Baclofen 50mcg/ml Pf Syr, 1ml
- Baclofen 25mg/5ml Oral Susp 300ml
- Baclofen 25mg/5ml Oral Susp 120ml
- Baclofen 15mg Tablets
- Baclofen 25mg/5ml Oral Susp 250ml
- Baclofen 2000mcg Inj Refill Kit
Dosing & Administration
Adult Dosing
Standard Dose:
Highly individualized. Screening dose: 50 mcg intrathecally, then 75 mcg, then 100 mcg at 24-hour intervals if no response. Initial daily dose (after pump implantation): typically twice the effective screening dose, administered over 24 hours. Maintenance dose: 300-800 mcg/day (median), adjusted based on response.
Dose Range:
12 - 2000 mg
Condition-Specific Dosing:
Spasticity of cerebral origin:
Initial daily dose may be lower than for spinal origin spasticity. Maintenance dose range typically 200-1000 mcg/day.
Spasticity of spinal origin:
Initial daily dose typically 300-400 mcg/day. Maintenance dose range typically 300-800 mcg/day.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established (approved for children âĨ4 years)
Child:
Screening dose: 25-50 mcg intrathecally. Initial daily dose (after pump implantation): typically 1.5 to 2 times the effective screening dose. Maintenance dose: Median 274 mcg/day, range 24-1200 mcg/day. Dosing is highly individualized based on patient response and age (approved for âĨ4 years).
Adolescent:
Similar to adult dosing, highly individualized based on response.
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment required for intrathecal administration due to minimal systemic absorption. Monitor for systemic side effects if any.
Moderate:
No specific adjustment required for intrathecal administration due to minimal systemic absorption. Monitor for systemic side effects if any.
Severe:
No specific adjustment required for intrathecal administration due to minimal systemic absorption. Monitor for systemic side effects if any.
Dialysis:
Not applicable for intrathecal administration as systemic exposure is minimal. However, if systemic absorption occurs (e.g., pump malfunction), baclofen is dialyzable.
Hepatic Impairment:
Mild:
No specific adjustment required for intrathecal administration due to minimal systemic absorption and metabolism.
Moderate:
No specific adjustment required for intrathecal administration due to minimal systemic absorption and metabolism.
Severe:
No specific adjustment required for intrathecal administration due to minimal systemic absorption and metabolism.
Pharmacology
Mechanism of Action
Baclofen is a gamma-aminobutyric acid (GABA) derivative that acts as a GABA-B receptor agonist. It is thought to produce its antispasticity effects by inhibiting both monosynaptic and polysynaptic reflexes at the spinal cord level, primarily by hyperpolarizing afferent terminals and inhibiting the release of excitatory neurotransmitters (e.g., glutamate, aspartate).
Pharmacokinetics
Absorption:
Bioavailability:
Not applicable (directly administered into CSF)
Tmax:
CSF concentrations peak within hours (typically 1-4 hours after bolus)
FoodEffect:
Not applicable (intrathecal administration)
Distribution:
Vd:
Limited to CSF space (approximately 150 mL in adults)
ProteinBinding:
<30% in CSF
CnssPenetration:
Yes (direct administration)
Elimination:
HalfLife:
1.5 hours (in CSF)
Clearance:
Not well-defined for CSF, primarily renal excretion of unchanged drug systemically
ExcretionRoute:
Renal (primarily unchanged drug systemically)
Unchanged:
>80% (systemically)
Pharmacodynamics
OnsetOfAction:
0.5-1 hour (after bolus)
PeakEffect:
3-4 hours (after bolus)
DurationOfAction:
4-8 hours (after bolus); continuous infusion provides sustained effect
Safety & Warnings
BLACK BOX WARNING
Abrupt discontinuation of intrathecal baclofen, regardless of the cause, has resulted in severe withdrawal symptoms including high fever, altered mental status, exaggerated rebound spasticity, and muscle rigidity, that in rare cases have advanced to rhabdomyolysis, multi-organ system failure, and death. Prevention of abrupt discontinuation of intrathecal baclofen requires careful attention to refill scheduling and pump alarms. Patients and caregivers should be advised of the importance of regular pump refills and to recognize the symptoms of withdrawal.
Side Effects
Serious Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Severe dizziness or fainting
Confusion
New or worsening mental, mood, or behavioral changes
Hallucinations (seeing or hearing things that are not there)
Seizures
Changes in balance or coordination
Vision changes
Chest pain
Muscle pain or weakness
Muscle stiffness
Abnormal burning, numbness, or tingling sensations
Breathing difficulties, slow breathing, or shallow breathing
Urination problems, such as:
+ Inability to pass urine
+ Changes in urine frequency or amount
+ Blood in the urine
Swelling in the arms or legs
Trouble controlling body movements, twitching, or changes in balance
Difficulty swallowing or speaking
Uncontrolled eye movements
Abnormal heartbeat
Other Possible Side Effects
Like all medications, this drug can cause side effects. Many people may not experience any side effects or may only have mild ones. If you are bothered by any of the following side effects or if they do not go away, contact your doctor:
Dizziness, drowsiness, fatigue, or weakness
Sleep disturbances
Upset stomach or vomiting
Headache
Constipation
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Severe dizziness or fainting
Confusion
New or worsening mental, mood, or behavioral changes
Hallucinations (seeing or hearing things that are not there)
Seizures
Changes in balance or coordination
Vision changes
Chest pain
Muscle pain or weakness
Muscle stiffness
Abnormal burning, numbness, or tingling sensations
Breathing difficulties, slow breathing, or shallow breathing
Urination problems, such as:
+ Inability to pass urine
+ Changes in urine frequency or amount
+ Blood in the urine
Swelling in the arms or legs
Trouble controlling body movements, twitching, or changes in balance
Difficulty swallowing or speaking
Uncontrolled eye movements
Abnormal heartbeat
Other Possible Side Effects
Like all medications, this drug can cause side effects. Many people may not experience any side effects or may only have mild ones. If you are bothered by any of the following side effects or if they do not go away, contact your doctor:
Dizziness, drowsiness, fatigue, or weakness
Sleep disturbances
Upset stomach or vomiting
Headache
Constipation
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Overdose symptoms: Extreme drowsiness, profound muscle weakness (floppy muscles), shallow or slow breathing, dizziness, lightheadedness, feeling very cold, seizures, loss of consciousness.
- Withdrawal symptoms: Sudden increase in muscle stiffness/spasms, itching, high fever, confusion, hallucinations, changes in behavior, seizures, muscle breakdown (dark urine), organ failure.
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, any of its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced as a result of the allergy.
If you currently have an infection.
This list is not exhaustive, and it is crucial to discuss all your medications (including prescription, over-the-counter, natural products, and vitamins) and health issues with your doctor and pharmacist. They will help determine whether it is safe to take this medication in conjunction with your other medications and health conditions.
Remember, do not start, stop, or modify the dosage of any medication without first consulting your doctor to ensure your safety.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, any of its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced as a result of the allergy.
If you currently have an infection.
This list is not exhaustive, and it is crucial to discuss all your medications (including prescription, over-the-counter, natural products, and vitamins) and health issues with your doctor and pharmacist. They will help determine whether it is safe to take this medication in conjunction with your other medications and health conditions.
Remember, do not start, stop, or modify the dosage of any medication without first consulting your doctor to ensure your safety.
Precautions & Cautions
Important Warnings and Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
To ensure your safety, avoid driving and engaging in activities that require alertness until you understand how this medication affects you. Before consuming alcohol, using marijuana or other forms of cannabis, or taking prescription or over-the-counter (OTC) drugs that may impair your actions, consult with your doctor.
When administering this medication to a child, exercise caution, as the risk of certain side effects may be higher in pediatric patients.
If you are pregnant, planning to become pregnant, or breastfeeding, notify your doctor. You and your doctor will need to discuss the potential benefits and risks of this medication to both you and your baby. Taking this medication during pregnancy may increase the risk of withdrawal symptoms in the newborn.
Injection Administration
If you notice that this medication is no longer effective, consult with your doctor. Do not exceed the prescribed dose, as this can lead to adverse effects.
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
To ensure your safety, avoid driving and engaging in activities that require alertness until you understand how this medication affects you. Before consuming alcohol, using marijuana or other forms of cannabis, or taking prescription or over-the-counter (OTC) drugs that may impair your actions, consult with your doctor.
When administering this medication to a child, exercise caution, as the risk of certain side effects may be higher in pediatric patients.
If you are pregnant, planning to become pregnant, or breastfeeding, notify your doctor. You and your doctor will need to discuss the potential benefits and risks of this medication to both you and your baby. Taking this medication during pregnancy may increase the risk of withdrawal symptoms in the newborn.
Injection Administration
If you notice that this medication is no longer effective, consult with your doctor. Do not exceed the prescribed dose, as this can lead to adverse effects.
Overdose Information
Overdose Symptoms:
- Profound hypotonia (muscle flaccidity)
- Somnolence, dizziness, lightheadedness
- Respiratory depression, apnea
- Bradycardia
- Hypothermia
- Seizures
- Coma
What to Do:
Seek immediate emergency medical attention. Call 911 or your local emergency number. Management involves supportive care, including respiratory support, and potentially removal of baclofen from the CSF.
Drug Interactions
Major Interactions
Moderate Interactions
- Monoamine Oxidase Inhibitors (MAOIs): Concurrent use with oral baclofen has been reported to cause exaggerated CNS depression. Caution with intrathecal, though systemic exposure is minimal.
Monitoring
Baseline Monitoring
Spasticity assessment (e.g., Ashworth Scale, Modified Ashworth Scale)
Rationale: To establish baseline severity and type of spasticity for treatment efficacy evaluation.
Timing: Prior to screening dose and pump implantation.
Neurological examination
Rationale: To assess motor function, reflexes, and sensory status.
Timing: Prior to screening dose and pump implantation.
Psychological evaluation
Rationale: To assess patient's ability to understand and comply with treatment, and to identify any contraindications.
Timing: Prior to pump implantation.
Imaging (MRI/CT of spine)
Rationale: To assess spinal anatomy for catheter placement and rule out any contraindications.
Timing: Prior to pump implantation.
Routine Monitoring
Spasticity severity and functional improvement
Frequency: Daily during titration, then regularly (e.g., monthly, quarterly) during maintenance
Target: Reduction in spasticity to a level that improves function and reduces pain without excessive hypotonia.
Action Threshold: Significant increase in spasticity (potential withdrawal/underdosing) or excessive hypotonia/sedation (potential overdose/overdosing).
Adverse effects (e.g., sedation, hypotonia, nausea, headache, dizziness)
Frequency: Daily during titration, then at each refill visit and as needed
Target: Minimal to no adverse effects.
Action Threshold: Presence of significant or bothersome adverse effects requiring dose adjustment or intervention.
Pump reservoir volume and refill schedule
Frequency: At each refill visit (typically every 1-3 months)
Target: Adequate volume to prevent pump running dry.
Action Threshold: Low reservoir volume indicating need for immediate refill; missed refill appointments.
Pump function and catheter integrity
Frequency: At each refill visit and if symptoms of overdose/withdrawal occur
Target: Normal pump operation, no signs of catheter kink, fracture, or dislodgement.
Action Threshold: Alarm activation, unexpected changes in spasticity, or signs of pump/catheter malfunction.
Symptom Monitoring
- Signs of Baclofen Overdose: Profound hypotonia, somnolence, dizziness, lightheadedness, drowsiness, respiratory depression, apnea, bradycardia, hypothermia, seizures, coma.
- Signs of Baclofen Withdrawal: Increased spasticity, pruritus, hyperthermia, altered mental status (e.g., confusion, hallucinations), exaggerated rebound spasticity, muscle rigidity, rhabdomyolysis, multi-organ system failure, seizures, death.
Special Patient Groups
Pregnancy
Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. While systemic exposure from intrathecal administration is minimal, animal studies with oral baclofen have shown adverse effects. Data in pregnant women are limited.
Trimester-Specific Risks:
First Trimester:
Limited data; theoretical risk of teratogenicity based on animal studies with high oral doses.
Second Trimester:
Limited data; potential for fetal CNS depression if significant systemic exposure occurs.
Third Trimester:
Limited data; potential for neonatal withdrawal symptoms if significant systemic exposure occurs, though unlikely with intrathecal administration.
Lactation
Baclofen is excreted in breast milk after oral administration. Due to minimal systemic absorption with intrathecal administration, infant exposure is expected to be very low. However, caution should be exercised, and the benefits of breastfeeding weighed against potential risks.
Infant Risk:
Low (L3) due to minimal systemic exposure from intrathecal route, but monitor infant for sedation or hypotonia.
Pediatric Use
Approved for children aged 4 years and older for severe spasticity unresponsive to oral baclofen or other therapies. Dosing is highly individualized based on patient response and age. Careful monitoring for adverse effects is crucial, as children may be more sensitive to baclofen's effects.
Geriatric Use
Elderly patients may be more sensitive to the effects of baclofen, particularly CNS depression and hypotonia. Start with lower doses and titrate slowly. Monitor closely for adverse effects.
Clinical Information
Clinical Pearls
- Intrathecal baclofen therapy requires a multidisciplinary team approach, including a neurosurgeon, neurologist, and rehabilitation specialists.
- Abrupt discontinuation of intrathecal baclofen is a medical emergency and can be life-threatening. Patients and caregivers must be educated on the critical importance of pump refills and recognizing withdrawal symptoms.
- A screening test dose via lumbar puncture is essential to determine patient responsiveness before pump implantation.
- Dosing is highly individualized and requires careful titration to achieve optimal spasticity control with minimal side effects.
- Pump malfunction or catheter issues (e.g., kink, fracture, dislodgement) can lead to either overdose or withdrawal symptoms.
- Patients should carry an identification card indicating they have an implanted baclofen pump and the contact information for their treating physician.
Alternative Therapies
- Oral antispasticity agents (e.g., oral baclofen, tizanidine, dantrolene, diazepam)
- Botulinum toxin injections (for focal spasticity)
- Physical therapy and occupational therapy
- Surgical interventions (e.g., selective dorsal rhizotomy, orthopedic procedures)
- Nerve blocks
Cost & Coverage
Average Cost:
Highly variable, includes drug cost, pump cost, surgical implantation, and ongoing refills/maintenance. Can range from thousands to tens of thousands of dollars annually. per vial/per year (including pump and services)
Generic Available:
Yes
Insurance Coverage:
Specialty Tier / Medical Benefit (often covered under durable medical equipment and pharmacy benefit for refills)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide details about the overdose, including the medication taken, the amount, and the time it occurred.