Riluzole 50mg Tablets
It is used to treat amyotrophic lateral sclerosis (ALS).
Drug Class
Amyotrophic Lateral Sclerosis (ALS) Agent
Pharmacologic Class
Benzothiazole derivative; Glutamate release inhibitor
Pregnancy Category
C
FDA Approved
Dec 1995
DEA Schedule
Not Controlled
Overview
What is this medicine?
Riluzole is a medication used to treat Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig's disease. It is thought to work by protecting nerve cells in the brain and spinal cord from too much of a chemical called glutamate, which can damage these cells. While it is not a cure for ALS, it can help slow down the progression of the disease and may extend survival.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. Take your medication on an empty stomach, either at least 1 hour before or at least 2 hours after a meal. Establish a routine by taking your medication at the same time every day. Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better.
Storing and Disposing of Your Medication
To maintain the effectiveness and safety of your medication, store it at room temperature, protected from light and moisture. Avoid storing it in a bathroom. Keep all medications in a secure location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist. If you have questions about disposing of your medication, consult with your pharmacist, who can also inform you about potential drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember, provided you take it on an empty stomach. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Avoid taking two doses at the same time or taking extra doses, as this can increase the risk of side effects.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. Take your medication on an empty stomach, either at least 1 hour before or at least 2 hours after a meal. Establish a routine by taking your medication at the same time every day. Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better.
Storing and Disposing of Your Medication
To maintain the effectiveness and safety of your medication, store it at room temperature, protected from light and moisture. Avoid storing it in a bathroom. Keep all medications in a secure location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist. If you have questions about disposing of your medication, consult with your pharmacist, who can also inform you about potential drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember, provided you take it on an empty stomach. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Avoid taking two doses at the same time or taking extra doses, as this can increase the risk of side effects.
Lifestyle & Tips
- Take Riluzole on an empty stomach, at least 1 hour before or 2 hours after a meal, to ensure proper absorption.
- Do not drink alcohol while taking Riluzole, as it can increase the risk of liver problems.
- Avoid smoking, as it can reduce the effectiveness of Riluzole.
- Do not stop taking Riluzole without talking to your doctor, even if you feel better.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
50 mg orally every 12 hours
Dose Range:
50 - 50 mg
Condition-Specific Dosing:
ALS:
50 mg orally every 12 hours, taken at least 1 hour before or 2 hours after a meal.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No specific dose adjustment recommended, but use with caution.
Moderate:
No specific dose adjustment recommended, but use with caution.
Severe:
Not recommended due to lack of data and potential for increased exposure.
Dialysis:
Not recommended due to lack of data and potential for increased exposure.
Hepatic Impairment:
Mild:
Use with caution; monitor liver function closely.
Moderate:
Not recommended due to increased exposure and risk of liver injury.
Severe:
Contraindicated.
Confidence:
High
Pharmacology
Mechanism of Action
The mechanism by which riluzole exerts its therapeutic effect in patients with ALS is unknown. However, it is proposed to act by inhibiting glutamate release, inactivating voltage-dependent sodium channels, and interfering with intracellular events that follow transmitter binding at excitatory amino acid receptors. It may protect motor neurons from excitotoxicity.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 50%
Tmax:
60-90 minutes (oral solution), 1-1.5 hours (tablet)
FoodEffect:
High-fat meals decrease absorption (Cmax by 44%, AUC by 17%). Should be taken on an empty stomach.
Distribution:
Vd:
240 L (approximately 3.4 L/kg)
ProteinBinding:
Approximately 96% (primarily to albumin and alpha-1 acid glycoprotein)
CnssPenetration:
Yes
Elimination:
HalfLife:
9-15 hours
Clearance:
Approximately 15.4 L/hour
ExcretionRoute:
Urine (approximately 90%), Feces (approximately 5%)
Unchanged:
Less than 2% (urine)
Pharmacodynamics
OnsetOfAction:
Not acutely measurable; clinical benefit observed over months.
PeakEffect:
Not acutely measurable; clinical benefit observed over months.
DurationOfAction:
Not acutely measurable; continuous treatment required.
Safety & Warnings
BLACK BOX WARNING
Riluzole can cause liver injury. Liver function tests (ALT, AST, bilirubin) should be measured before and during treatment. Discontinue riluzole if ALT/AST levels are >5 times the upper limit of normal (ULN) or if ALT/AST levels are >3 times ULN and total bilirubin is >2 times ULN.
Side Effects
Serious Side Effects: Seek Medical Help Immediately
Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical attention right away:
Signs of an allergic reaction: 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, or swelling of the mouth, face, lips, tongue, or throat
Signs of high blood pressure: severe headache, dizziness, fainting, or changes in vision
Signs of lung or breathing problems: shortness of breath, difficulty breathing, cough, or fever
Liver problems: dark urine, fatigue, decreased appetite, nausea, stomach pain, pale stools, vomiting, or yellowing of the skin or eyes (jaundice)
Signs of infection (due to low white blood cell count): fever, chills, or sore throat
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. Contact your doctor or seek medical help if you experience:
Upset stomach
Stomach pain
Dizziness, fatigue, or weakness
Reporting Side Effects
This list is not exhaustive, and you may experience other 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, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical attention right away:
Signs of an allergic reaction: 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, or swelling of the mouth, face, lips, tongue, or throat
Signs of high blood pressure: severe headache, dizziness, fainting, or changes in vision
Signs of lung or breathing problems: shortness of breath, difficulty breathing, cough, or fever
Liver problems: dark urine, fatigue, decreased appetite, nausea, stomach pain, pale stools, vomiting, or yellowing of the skin or eyes (jaundice)
Signs of infection (due to low white blood cell count): fever, chills, or sore throat
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. Contact your doctor or seek medical help if you experience:
Upset stomach
Stomach pain
Dizziness, fatigue, or weakness
Reporting Side Effects
This list is not exhaustive, and you may experience other 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:
- Signs of liver problems: yellowing of the skin or eyes (jaundice), dark urine, severe nausea or vomiting, unusual tiredness, pain in the upper right side of the stomach.
- Signs of infection/low white blood cells: fever, chills, sore throat, mouth sores, unusual weakness.
- Signs of lung problems: new or worsening cough, shortness of breath, fever.
- Allergic reactions: rash, itching, swelling of the face/tongue/throat, severe dizziness, trouble breathing.
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, 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 have liver disease or elevated liver enzymes, as this may affect your ability to take this medication.
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. Additionally, share any health problems you have, as they may interact with this medication.
To ensure your safety, always check with your doctor before starting, stopping, or changing the dose of any medication. This will help prevent potential interactions and ensure that it is safe for you to take this medication with your other drugs and health conditions.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, 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 have liver disease or elevated liver enzymes, as this may affect your ability to take this medication.
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. Additionally, share any health problems you have, as they may interact with this medication.
To ensure your safety, always check with your doctor before starting, stopping, or changing the dose of any medication. This will help prevent potential interactions and ensure that it is safe for you to take this medication with your other drugs and health conditions.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Regularly undergo blood tests and other laboratory examinations as directed by your doctor to monitor your condition. If you are of Japanese descent, exercise caution when using this drug, as you may be more susceptible to side effects. Prior to initiating treatment, notify your doctor if you are pregnant, planning to become pregnant, or are breastfeeding, as this will require a discussion about the potential benefits and risks to both you and your baby.
Overdose Information
Overdose Symptoms:
- Acute neurological and psychiatric symptoms (e.g., acute toxic encephalopathy with coma, stupor, ataxia, dizziness, agitation, decreased consciousness)
- Cardiovascular symptoms (e.g., sinus bradycardia, QT prolongation)
- Liver enzyme elevation
What to Do:
Seek immediate medical attention or call a poison control center (1-800-222-1222). Treatment is supportive and symptomatic. There is no specific antidote.
Drug Interactions
Major Interactions
- Strong CYP1A2 inhibitors (e.g., fluvoxamine, ciprofloxacin, enoxacin): May significantly increase riluzole exposure, increasing risk of adverse effects. Consider dose reduction or avoid concomitant use.
- Hepatotoxic drugs (e.g., methotrexate, amiodarone, allopurinol, some antifungals): Increased risk of liver injury. Monitor LFTs closely.
Moderate Interactions
- Moderate CYP1A2 inhibitors (e.g., verapamil, mexiletine, propafenone): May increase riluzole exposure. Monitor for adverse effects.
- CYP1A2 inducers (e.g., rifampin, omeprazole, tobacco smoke): May decrease riluzole exposure, potentially reducing efficacy. Monitor clinical response.
- Alcohol: Increased risk of liver injury.
Minor Interactions
- Not specifically identified as minor interactions with significant clinical impact.
Monitoring
Baseline Monitoring
Liver Function Tests (ALT, AST, bilirubin)
Rationale: Riluzole can cause dose-dependent liver injury, including severe hepatic injury.
Timing: Before starting treatment.
Complete Blood Count (CBC) with differential
Rationale: Riluzole has been associated with neutropenia.
Timing: Before starting treatment.
Routine Monitoring
Liver Function Tests (ALT, AST)
Frequency: Monthly for the first 3 months of treatment, every 3 months for the remainder of the first year, and periodically thereafter.
Target: Within normal limits or stable baseline.
Action Threshold: Discontinue riluzole if ALT/AST levels are >5 times the upper limit of normal (ULN) or if ALT/AST levels are >3 times ULN and total bilirubin is >2 times ULN.
Complete Blood Count (CBC) with differential
Frequency: Periodically, especially if signs of infection develop.
Target: Within normal limits.
Action Threshold: Discontinue riluzole if neutrophil count falls below 1000/mm³.
Symptom Monitoring
- Signs and symptoms of liver injury (e.g., nausea, vomiting, abdominal pain, fatigue, dark urine, jaundice, pruritus)
- Signs and symptoms of neutropenia/infection (e.g., fever, chills, sore throat, mouth sores, unusual bleeding/bruising)
- Signs and symptoms of interstitial lung disease (e.g., dry cough, dyspnea, fever)
Special Patient Groups
Pregnancy
Riluzole is Pregnancy Category C. There are no adequate and well-controlled studies in pregnant women. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Animal studies showed developmental toxicity (reduced fetal weight, skeletal ossification delays) at doses higher than human therapeutic doses.
Second Trimester:
Risk not well-established in humans; animal data suggest potential for developmental effects.
Third Trimester:
Risk not well-established in humans; animal data suggest potential for developmental effects.
Lactation
It is not known whether riluzole is excreted in human milk. Due to the potential for serious adverse reactions in breastfed infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Infant Risk:
L3 (Moderate risk - no human data, but potential for adverse effects based on drug properties and animal data).
Pediatric Use
Safety and effectiveness in pediatric patients have not been established. Riluzole is not recommended for use in pediatric patients.
Geriatric Use
No specific dose adjustment is required based on age alone. However, elderly patients may have reduced renal or hepatic function, which should be considered. Monitor liver function closely.
Clinical Information
Clinical Pearls
- Riluzole is the first FDA-approved drug for ALS and has been shown to extend survival by approximately 2-3 months.
- It is crucial to monitor liver function tests (ALT/AST) regularly, especially during the first year of treatment, due to the risk of hepatotoxicity.
- Patients should be educated on the signs and symptoms of liver injury and neutropenia and instructed to report them immediately.
- Administer on an empty stomach for optimal absorption.
- Oral suspension (Tiglutik, Exservan) and oral film (Exservan) formulations are available for patients with dysphagia.
Alternative Therapies
- Edaravone (Radicava, Radicava ORS)
- Tofersen (Qalsody) - for SOD1-ALS
- Sodium Phenylbutyrate/Taurursodiol (Relyvrio) - recently withdrawn from market due to failed confirmatory trial, but was an alternative.
- Non-pharmacological supportive care (e.g., respiratory support, nutritional support, physical therapy, occupational therapy, speech therapy).
Cost & Coverage
Average Cost:
$1000 - $2000+ per 60 tablets (50mg)
Generic Available:
Yes
Insurance Coverage:
Tier 3 / Specialty Drug (requires prior authorization)
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 your 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 emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.