Skip to Content

Riluzole Side Effects

In Summary

Commonly reported side effects of riluzole include: weakness, nausea, and increased serum alanine aminotransferase. Other side effects include: vomiting. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to riluzole: oral tablet

As well as its needed effects, riluzole may cause unwanted side effects that require medical attention.

Major Side Effects

If any of the following side effects occur while taking riluzole, check with your doctor immediately:

More common:
  • Blurred vision
  • difficulty with breathing
  • difficulty with moving
  • dizziness
  • excessive muscle tone
  • headache
  • increased cough
  • muscle pain or stiffness
  • muscle tension or tightness
  • nervousness
  • pain in the joints
  • pounding in the ears
  • slow or fast heartbeat
Less common:
  • Bladder pain
  • bloating or swelling of the face, arms, hands, lower legs, or feet
  • bloody or cloudy urine
  • bluish lips or skin
  • burning while urinating
  • changes in skin color
  • chest congestion
  • chest pain
  • chills
  • cold sweats
  • confusion
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • cough
  • cough producing mucus
  • diarrhea
  • difficult, burning, or painful urination
  • difficult or labored breathing
  • difficulty with swallowing
  • fast, pounding, or irregular heartbeat or pulse
  • fever
  • frequent urge to urinate
  • general feeling of discomfort or illness
  • headache
  • increased sputum
  • loss of appetite
  • low blood pressure or pulse
  • lower back or side pain
  • muscle aches and pains
  • nausea
  • pain
  • rapid weight gain
  • runny nose
  • shivering
  • shortness of breath
  • slow breathing
  • sneezing
  • sore throat
  • sweating
  • tenderness
  • tightness in the chest
  • tingling of the hands or feet
  • trouble sleeping
  • troubled breathing
  • unconsciousness
  • unusual tiredness or weakness
  • unusual weight gain or loss
  • vomiting
  • wheezing
  • Continuing sores in the mouth
  • convulsions
  • increased thirst
  • lack of coordination
  • lack of energy
  • mental depression
  • mood or mental changes
  • muscle cramps, pain, or weakness
  • pain, tenderness, bluish color, or swelling of the foot or leg
  • redness, scaling, or peeling of the skin
  • swelling of the eyelids, mouth, lips, tongue, or throat
  • swelling of the face
  • yellow eyes or skin

Minor Side Effects

Some riluzole side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

More common:
  • Abdominal or stomach pain
  • acid or sour stomach
  • belching
  • drowsiness
  • heartburn
  • indigestion
  • lack or loss of strength
  • numbness or tingling around the mouth
  • pain or tenderness around the eyes and cheekbones
  • stomach discomfort, upset, or pain
  • weight loss
Less common:
  • Back or muscle pain or stiffness
  • constipation
  • cracks in the skin
  • dizziness or lightheadedness
  • dry mouth
  • excess air or gas in the stomach or intestines
  • feeling of constant movement of self or surroundings
  • full feeling
  • general feeling of discomfort or illness
  • hair loss or thinning of the hair
  • irritation or soreness of the mouth
  • itching skin
  • loss of heat from the body
  • passing gas
  • sensation of spinning
  • skin rash, encrusted, scaly, and oozing
  • sleepiness or unusual drowsiness
  • sleeplessness
  • sore mouth or tongue
  • swelling or inflammation of the mouth
  • tooth problems
  • unable to sleep
  • white patches in the mouth, tongue, or throat

For Healthcare Professionals

Applies to riluzole: oral tablet


At least one elevation in ALT has occurred in 50% of patients receiving riluzole. An ALT greater than 5 times the upper limit of normal has occurred in approximately 2% of patients. These elevations tend to occur within the first 3 months of treatment, are usually transient if less than 5 times the upper limit of normal, and may return to normal within 2 to 6 months if therapy is continued. There is little experience in the management of patients whose ALT exceeds 5 times the upper limit of normal. The manufacturer recommends discontinuing the drug if ALT exceeds 10 times the upper limit of normal or if jaundice occurs.

In one patient receiving riluzole for epilepsy and concurrently taking phenobarbital and carbamazepine, clinical jaundice developed four months after starting riluzole (ALT 26 X ULN, AST 17 X ULN, and bilirubin 11 X ULN). Liver function tests returned to normal 7 weeks after discontinuing riluzole therapy.[Ref]

Hepatic side effects including elevations in alanine aminotransferase (ALT), aspartate aminotransferase (AST), and jaundice have been reported. Cases of clinical hepatitis associated with riluzole have been reported, including one with a fatal outcome.[Ref]


Most gastrointestinal side effects have been dose-related. Nausea and abdominal pain commonly resulted in discontinuation of riluzole during clinical trials.[Ref]

Gastrointestinal side effects have included nausea (16.3%), abdominal pain (5.1%), vomiting (4.2%), anorexia (3.2%), and diarrhea (2.9%). Two cases of pancreatitis have also been reported.[Ref]


Musculoskeletal side effects including asthenia (which appears to be dose-related) (19.2%) and muscle stiffness have been reported.[Ref]


Respiratory side effects including cases of interstitial lung disease have been reported in patients treated with riluzole, some of them severe. Upon further investigation, many of these cases were hypersensitivity pneumonitis.

Nervous system

Nervous system side effects appear to be dose-related. Dizziness occurred more frequently in female patients.[Ref]

Nervous system side effects including dizziness (3.8%), vertigo (1.9%), circumoral paresthesias (1.6%) and somnolence (1.9%) have been reported.[Ref]


Hematologic side effects including anemia and neutropenia (absolute neutrophil count less than 500/mm3) have rarely been reported. A case of methemoglobinemia has also been reported.[Ref]


Cardiovascular side effects including mild to moderate increases in blood pressure have been reported.[Ref]


Hypersensitivity side effects including anaphylaxis have been reported.


1. "Product Information. Rilutek (riluzole)." Rhone-Poulenc Rorer, Collegeville, PA.

2. Bensimon G, Lacomblez L, Meininger V "A controlled trial of riluzole in amyotrophic lateral sclerosis. ALS/Riluzole Study Group." N Engl J Med 330 (1994): 585-91

3. Drory VE, Sidi I, Korczyn AD "Riluzole-induced pancreatitis." Neurology 52 (1999): 892-3

4. Rodrigo L, Moreno M, Calleja S, Mateos V, Andrade RJ, Lucena MI "Riluzole-induced acute pancreatitis." Am J Gastroenterol 96 (2001): 2268-9

5. Woolf A, Carstairs SD, Tanen DA "Riluzole-induced methemoglobinemia." Ann Emerg Med 43 (2004): 294

6. Weber G, Bitterman H "Riluzole-induced neutropenia." Neurology 62 (2004): 1648

It is possible that some side effects of riluzole may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.