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Riluzole Side Effects

In Summary

Commonly reported side effects of riluzole include: asthenia, 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:

Less common:
  • Bladder pain
  • bloody or cloudy urine
  • blurred vision
  • dark urine
  • difficult, burning, or painful urination
  • fast, pounding, or irregular heartbeat or pulse
  • flu-like symptoms
  • frequent urge to urinate
  • headache
  • increased cough
  • itching skin
  • lower back or side pain
  • nervousness
  • persistent anorexia
  • pounding in the ears
  • right upper quadrant tenderness
  • slow heartbeat
  • yellow eyes or skin
Incidence not known:
  • Black, tarry, stools
  • chills
  • cough
  • decreased frequency or amount of urine
  • difficult breathing
  • fever
  • increased thirst
  • loss of appetite
  • nausea
  • pale skin
  • sore throat
  • swelling of the face, fingers, or lower legs
  • ulcers, sores, or white spots in the mouth
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • vomiting
  • weight gain

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:
  • Lack or loss of strength
Less common:
  • Abdominal or stomach pain
  • bloating or swelling of the face, arms, hands, lower legs, or feet
  • difficulty moving
  • dizziness or lightheadedness
  • dry mouth
  • excess air or gas in the stomach or intestines
  • feeling of constant movement of self or surroundings
  • full feeling
  • muscle pain or stiffness
  • pain in the joints
  • passing gas
  • rapid weight gain
  • sensation of spinning
  • skin rash, encrusted, scaly and oozing
  • sleepiness or unusual drowsiness
  • tingling of the hands or feet
  • trouble sleeping
  • unusual weight gain or loss

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. 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

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

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

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

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.

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