Reviewed on 7/6/2022

What Is Riluzole and How Does It Work?

Riluzole is a prescription medication used for the treatment of amyotrophic lateral sclerosis

What Are Dosages of Riluzole?

Adult  dosage


  • 50 mg

Oral suspension

  • 5 mg /mL (300-mL multidose bottle)

Oral film

  • 50 mg

Amyotrophic Lateral Sclerosis

Adult dosage

  • 50 mg orally every 12 hours

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Are Side Effects Associated with Using Riluzole?

Common side effects of Riluzole include:

  • weakness,
  • drowsiness,
  • nausea,
  • stomach pain,
  • dizziness,
  • spinning sensation,
  • decreased lung function,
  • diarrhea,
  • constipation,
  • muscle stiffness,
  • numbness or tingly feeling in or around the mouth,
  • headache,
  • lightheadedness,
  • tiredness,
  • vomiting,
  • loss of appetite, or
  • runny nose.

Serious side effects of Riluzole include:

  • sudden chest pain, wheezing, feeling short of breath;
  • dry cough, or cough with mucus;
  • low white blood cell counts--fever, mouth sores, skin sores, sore throat; or
  • liver problems--nausea, loss of appetite, stomach pain (upper right side), tiredness, itching, dark urine, jaundice (yellowing of the skin or eyes).

Rare side effects of Riluzole include:

  • none

Seek medical care or call 911 at once if you have the following serious side effects:

  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheartedness, or passing out.
This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Riluzole?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Riluzole?


  • Hypersensitivity to drug or any component of the formulation

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Riluzole?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Riluzole?”


  • Cases of severe neutropenia (absolute neutrophil count less than 500/mm3) within the first 2 months of treatment reported; advise patients to report febrile illnesses
  • Interstitial lung disease, including hypersensitivity pneumonitis, is reported in patients receiving therapy; discontinue immediately if interstitial lung disease develops
  • Hepatic injury
  • Cases of drug-induced liver injury were reported; asymptomatic elevations of hepatic transaminases were reported and recurred in some patients upon rechallenging treatment (see Dosage Modifications)
  • Monitor patients for signs and symptoms of hepatic injury, every month for the first 3 months of treatment, and periodically thereafter; use is not recommended if patients develop hepatic transaminase levels greater than 5 times the ULN; discontinue therapy if there is evidence of liver dysfunction (e.g., elevated bilirubin)
  • Case reports of clinical hepatitis reported
  • Drug interactions overview
  • Riluzole is a CYP1A substrate
  • CYP1A2 inhibitors
    • In vitro findings suggest coadministration of riluzole with CYP1A2 inhibitors may increase in riluzole exposure
    • Coadministration with strong or moderate CYP1A2 inhibitors (eg, ciprofloxacin, enoxacin, fluvoxamine, methoxsalen, mexiletine, oral contraceptives, thiabendazole, vemurafenib, zileuton) may increase risk of riluzole-associated adverse reactions
  • CYP1A2 inducers
    • In vitro findings suggest coadministration with CYP1A2 inducers may decrease riluzole exposure, which may result in decreased efficacy
  • Hepatotoxic drugs

Pregnancy & Lactation

  • There are no studies on pregnant women, and case reports have been inadequate to inform of drug-associated risk
  • Unknown if the risk of major birth defects and miscarriage in patients with amyotrophic lateral sclerosis
  • Lactation
    • Unknown if distributed in human breast milk
    • Riluzole or its metabolites have been detected in the milk of lactating rat
    • Consider the developmental and health benefits of breastfeeding along with the mother’s clinical need for the drug, and any potential adverse effects on the breastfed infant from the drug or from the underlying maternal condition

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