Baclofen 20mg/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
GABA-B receptor agonist
Pregnancy Category
Category C
FDA Approved
Dec 1992
DEA Schedule
Not Controlled
Overview
What is this medicine?
Baclofen is a medicine that helps relax very stiff muscles (spasticity) caused by conditions like multiple sclerosis, spinal cord injury, or cerebral palsy. It is given directly into the fluid around your spinal cord using a special pump, which allows it to work where it's needed most with fewer side effects than oral medications.
How to Use This Medicine
To use this medication correctly, follow your doctor's instructions and carefully read all accompanying information. Adhere to the dosage instructions provided by your healthcare team. 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 dose, contact your doctor promptly to receive guidance on the next steps to take.
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 dose, contact your doctor promptly to receive guidance on the next steps to take.
Lifestyle & Tips
- Always carry an identification card stating you have an intrathecal pump and are receiving baclofen.
- Do not miss scheduled pump refill appointments, as abrupt discontinuation can be life-threatening.
- Report any changes in your spasticity, muscle weakness, or any new or worsening side effects to your doctor immediately.
- Avoid activities that could damage your pump or catheter.
- Be aware of symptoms of overdose (extreme drowsiness, weakness, shallow breathing) and withdrawal (fever, confusion, severe muscle stiffness, seizures) and seek immediate medical attention if they occur.
- Avoid alcohol and other sedating medications unless approved by your doctor, as they can increase drowsiness.
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. Initial test dose followed by titration to maintenance dose.
Dose Range:
300 - 1000 mg
Condition-Specific Dosing:
severe_spasticity_of_spinal_origin:
Initial test dose: 50 mcg over 1 minute. If inadequate response after 24 hours, administer 75 mcg. If still inadequate after 24 hours, administer 100 mcg. Maintenance dose: After a positive response to a test dose, the initial daily dose is typically 1/3 to 1/4 of the test dose that produced a positive response, administered over 24 hours. Doses are then slowly titrated based on patient response, typically ranging from 300 mcg to 1000 mcg per day. Maximum daily dose rarely exceeds 2000 mcg/day.
severe_spasticity_of_cerebral_origin:
Initial test dose: 25 mcg over 1 minute. If inadequate response after 24 hours, administer 50 mcg. If still inadequate after 24 hours, administer 75 mcg. Maintenance dose: Similar titration as for spinal origin, but typically lower doses are required. Average daily dose for cerebral origin spasticity is 200-700 mcg/day.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Approved for severe spasticity unresponsive to oral therapy. Test dose: 25-50 mcg. Maintenance doses typically range from 200 mcg to 1000 mcg per day, but can vary widely based on individual response and condition.
Adolescent:
Similar individualized approach as adults, with test doses and titration based on response.
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment required due to minimal systemic exposure with intrathecal administration.
Moderate:
No specific adjustment required due to minimal systemic exposure with intrathecal administration.
Severe:
No specific adjustment required due to minimal systemic exposure with intrathecal administration. Use with caution and monitor for systemic effects if any.
Dialysis:
No specific adjustment required for patients on dialysis due to minimal systemic exposure with intrathecal administration.
Hepatic Impairment:
Mild:
No specific adjustment required due to minimal systemic exposure with intrathecal administration.
Moderate:
No specific adjustment required due to minimal systemic exposure with intrathecal administration.
Severe:
No specific adjustment required due to minimal systemic exposure with intrathecal administration.
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. This action leads to hyperpolarization of afferent terminals and inhibition of the release of excitatory neurotransmitters, thereby reducing muscle spasticity.
Pharmacokinetics
Absorption:
Bioavailability:
100% (to CSF)
Tmax:
CSF concentrations peak within hours (typically 0.5-1 hour after bolus, sustained with continuous infusion)
FoodEffect:
Not applicable (intrathecal administration)
Distribution:
Vd:
Not precisely quantified for CSF, but limited to CSF space initially
ProteinBinding:
Approximately 30%
CnssPenetration:
Yes (direct administration into CSF)
Elimination:
HalfLife:
CSF half-life: Approximately 1.5 hours; Systemic half-life: 2.5-4 hours (if absorbed systemically)
Clearance:
Primarily via CSF circulation and subsequent systemic absorption and renal excretion.
ExcretionRoute:
Renal (primarily unchanged)
Unchanged:
Approximately 70-80% (renally)
Pharmacodynamics
OnsetOfAction:
0.5-1 hour (after intrathecal bolus)
PeakEffect:
3-4 hours (after intrathecal bolus)
DurationOfAction:
4-8 hours (after single intrathecal bolus; continuous infusion provides sustained effect)
Safety & Warnings
BLACK BOX WARNING
Abrupt discontinuation of intrathecal baclofen, regardless of the cause, has resulted in severe adverse events, including high fever, altered mental status, exaggerated spasticity, muscle rigidity, and in rare cases, rhabdomyolysis, multiple organ-system failure, and death. Patients and caregivers should be fully informed of the importance of regular pump refills and the risks of abrupt discontinuation. Special attention should be given to patients at risk for withdrawal (e.g., spinal cord injury, cerebral palsy, traumatic brain injury).
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you experience any of the following symptoms, contact your doctor or seek medical attention immediately:
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 behavior changes
Hallucinations (seeing or hearing things that are not there)
Seizures
Changes in balance or coordination
Changes in eyesight
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 experience any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Dizziness, drowsiness, tiredness, or weakness
Sleep disturbances
Upset stomach or vomiting
Headache
Constipation
Reporting Side Effects
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you experience any of the following symptoms, contact your doctor or seek medical attention immediately:
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 behavior changes
Hallucinations (seeing or hearing things that are not there)
Seizures
Changes in balance or coordination
Changes in eyesight
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 experience any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Dizziness, drowsiness, tiredness, or weakness
Sleep disturbances
Upset stomach or vomiting
Headache
Constipation
Reporting Side Effects
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact 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:
- Signs of overdose: profound drowsiness, extreme muscle weakness, shallow or slow breathing, lightheadedness, dizziness, loss of consciousness, seizures.
- Signs of withdrawal: high fever, confusion, hallucinations, severe increase in muscle stiffness or spasms, muscle rigidity, itching, low blood pressure, seizures, rhabdomyolysis (muscle breakdown).
- Signs of pump or catheter problems: pain, redness, swelling, or warmth at the pump site; pump alarms; sudden return of spasticity.
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 allergic reaction you experienced, including any symptoms that occurred.
If you currently have an infection.
This is not an exhaustive list of all potential interactions with this medication. Therefore, it is crucial to discuss the following with your doctor and pharmacist:
All medications you are taking, including prescription and over-the-counter drugs, natural products, and vitamins.
Any health problems you have.
To ensure your safety, carefully review all your medications and health conditions with your doctor before taking this medication. Do not start, stop, or modify the dose of any medication without first consulting your doctor to confirm that it is safe to do so.
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 allergic reaction you experienced, including any symptoms that occurred.
If you currently have an infection.
This is not an exhaustive list of all potential interactions with this medication. Therefore, it is crucial to discuss the following with your doctor and pharmacist:
All medications you are taking, including prescription and over-the-counter drugs, natural products, and vitamins.
Any health problems you have.
To ensure your safety, carefully review all your medications and health conditions with your doctor before taking this medication. Do not start, stop, or modify the dose of any medication without first consulting your doctor to confirm that it is safe to do so.
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, marijuana, or other forms of cannabis, or taking prescription or over-the-counter (OTC) drugs that may cause drowsiness, 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 lead to 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, marijuana, or other forms of cannabis, or taking prescription or over-the-counter (OTC) drugs that may cause drowsiness, 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 lead to 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 muscle weakness (hypotonia)
- Somnolence, drowsiness, lightheadedness, dizziness
- Respiratory depression (slow, shallow breathing)
- Bradycardia (slow heart rate)
- Hypothermia (low body temperature)
- Seizures
- Coma
What to Do:
Seek immediate medical attention. Call 911 or your local emergency number. Management is primarily supportive: maintain airway, assist ventilation if necessary, monitor vital signs. Physostigmine has been used off-label in some cases to reverse CNS effects, but its use is controversial and should only be considered by specialists. Do NOT induce vomiting.
Drug Interactions
Major Interactions
- CNS depressants (e.g., opioids, benzodiazepines, sedatives, hypnotics, general anesthetics): May potentiate CNS depression, including respiratory depression and sedation.
- Tricyclic antidepressants (TCAs): May potentiate hypotonia.
Moderate Interactions
- Alcohol: Additive CNS depressant effects.
- Antihypertensives: May cause additive hypotensive effects.
Confidence Interactions
Monitoring
Baseline Monitoring
Spasticity assessment (e.g., Ashworth Scale, Penn Spasm Frequency Scale)
Rationale: To establish baseline severity and guide initial dosing.
Timing: Prior to test dose and initiation of therapy.
Neurological examination
Rationale: To assess motor function, reflexes, and sensory status.
Timing: Prior to test dose and initiation of therapy.
Vital signs (blood pressure, heart rate, respiratory rate)
Rationale: To establish baseline and monitor for adverse effects.
Timing: Prior to test dose and initiation of therapy.
Renal and hepatic function tests
Rationale: Although systemic exposure is minimal, baseline assessment is prudent.
Timing: Prior to initiation of therapy.
Routine Monitoring
Spasticity assessment
Frequency: Daily during titration, then regularly during maintenance (e.g., monthly to quarterly or as needed)
Target: Reduction in spasticity symptoms to improve function and comfort without excessive weakness.
Action Threshold: Inadequate spasticity control or excessive hypotonia/weakness requires dose adjustment.
Adverse effects (e.g., sedation, hypotonia, respiratory depression, nausea, headache, dizziness)
Frequency: Continuously during titration, then regularly during maintenance (e.g., at each refill visit)
Target: Absence or minimal tolerable adverse effects.
Action Threshold: Presence of significant or intolerable adverse effects requires dose adjustment or intervention.
Vital signs (especially respiratory rate)
Frequency: Frequently during titration, then periodically during maintenance (e.g., at each refill visit)
Target: Within normal limits for the patient.
Action Threshold: Significant changes, especially respiratory depression, require immediate intervention.
Pump function and reservoir volume
Frequency: At each refill visit (typically every 1-3 months)
Target: Adequate drug remaining, proper pump operation.
Action Threshold: Low reservoir volume, pump malfunction, or alarm requires immediate attention.
Symptom Monitoring
- Excessive drowsiness or sedation
- Profound muscle weakness or hypotonia
- Shallow or slow breathing (respiratory depression)
- Lightheadedness or dizziness
- Nausea or vomiting
- Headache
- Confusion or altered mental status (especially with withdrawal)
- High fever (with withdrawal)
- Exaggerated spasticity or muscle rigidity (with withdrawal)
- Seizures (with withdrawal)
- Itching or rash at the pump site
- Signs of infection (fever, redness, swelling, pain at pump site)
Special Patient Groups
Pregnancy
Category C. Baclofen should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Limited human data are available.
Trimester-Specific Risks:
First Trimester:
Potential for developmental abnormalities cannot be ruled out based on animal studies, but human data are limited.
Second Trimester:
Limited human data; risk appears low but caution advised.
Third Trimester:
Limited human data; risk appears low but caution advised. Neonatal withdrawal symptoms have been reported following maternal use of oral baclofen near term.
Lactation
L3 (Moderately safe). Baclofen is excreted into breast milk in small amounts. No adverse effects have been reported in breastfed infants. Monitor infant for sedation or unusual drowsiness.
Infant Risk:
Low risk; monitor for sedation.
Pediatric Use
Approved for severe spasticity in children aged 4 years and older who are unresponsive to oral baclofen or who experience intolerable side effects at effective oral doses. Dosing is highly individualized and requires careful titration. Safety and efficacy in children younger than 4 years have not been established.
Geriatric Use
Use with caution in elderly patients. Start with lower doses and titrate slowly due to increased sensitivity to adverse effects (e.g., sedation, weakness) and potential for altered pharmacokinetics or comorbidities. Monitor closely for CNS depression and hypotonia.
Clinical Information
Clinical Pearls
- Intrathecal baclofen therapy requires a multidisciplinary team approach, including a neurosurgeon or pain specialist for pump implantation and management, and ongoing medical supervision.
- The 20mg/20ml concentration means 1mg/ml. Intrathecal doses are typically in micrograms (mcg), so careful calculation and dilution may be necessary depending on the pump and patient needs.
- Abrupt withdrawal 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.
- Patients should carry an identification card or wear a medical alert bracelet indicating they have an intrathecal pump and are receiving baclofen.
- Overdose symptoms can mimic withdrawal symptoms in some aspects (e.g., altered mental status, respiratory depression), requiring careful differential diagnosis.
- Tolerance to baclofen's effects can develop over time, necessitating dose increases. However, rapid dose escalation should be avoided.
- MRI compatibility of the pump system must be confirmed before any MRI procedures.
Alternative Therapies
- Oral baclofen
- Tizanidine (oral)
- Dantrolene (oral)
- Botulinum toxin injections (e.g., Botox, Myobloc, Dysport)
- Benzodiazepines (e.g., diazepam, clonazepam)
- Physical therapy
- Occupational therapy
- Surgical interventions (e.g., selective dorsal rhizotomy, tenotomy)
- Nerve blocks
Cost & Coverage
Average Cost:
Varies widely, typically $500 - $1500+ per 20mg/20ml vial
Generic Available:
Yes
Insurance Coverage:
Specialty tier, often requires prior authorization and may be covered under medical benefit (for pump refills) rather than pharmacy benefit.
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 reporting the incident, be prepared to provide details about the medication taken, the amount, and the time it occurred.