Classifications: amyotrophic lateral sclerosis (als) agent; glutamate antagonist;
Therapeutic: als agent

Pregnancy Category: C


50 mg tablets


Glutamate antagonist used for treating amyotrophic lateral sclerosis (ALS). Inhibits the presynaptic release of glutamic acid in the CNS. Effectiveness based on hypothesis that pathogenesis of ALS is related to injury of motor neurons by glutamate.

Therapeutic Effect

Believed to reduce the degeneration of neurons that occurs in ALS.


Treatment of ALS, may extend survival or time to tracheostomy.


Hypersensitivity to riluzole; pregnancy (category C); lactation.

Cautious Use

Hepatic dysfunction, renal impairment; hypertension, history of other CNS disorders. Safe use in children <12 y is not established.

Route & Dosage

Adult: PO 50 mg q12h at least 1 h before or 2 h after meals


  • Give at same time daily and at least 1 h before or 2 h after a meal. Do not give before/after a high-fat meal.
  • Store at room temperature; protect from bright light.

Adverse Effects (≥1%)

Body as a Whole: Asthenia, headache, back pain, malaise, arthralgia, weight loss, peripheral edema, flu-like syndrome. CNS: Hypertonia, depression, dizziness, dry mouth, insomnia, somnolence, circumoral paresthesia. CV: Hypertension, tachycardia, phlebitis, palpitation. GI: Abdominal pain, nausea, vomiting, dyspepsia, anorexia, diarrhea, flatulence, stomatitis. Respiratory: Decreased lung function, rhinitis, increased cough, apnea, bronchitis, dysphagia, dyspnea. Skin: Pruritus, eczema, alopecia, exfoliative dermatitis (rare). Urogenital: UTI.


Drug: barbiturates, carbamazepine may increase risk of hepatotoxicity.


Absorption: Well absorbed from GI tract, 60% reaches systemic circulation. Peak: Steady-state levels by day 5. Distribution: 96% protein bound. Metabolism: In liver by cytochrome P4501A2 (CYP1A2). Elimination: 90% in urine. Half-Life: 12 h.

Nursing Implications

Assessment & Drug Effects

  • Lab tests: Monitor periodically Hct and Hgb, routine blood chemistries, and alkaline phosphatase. If febrile illness develops, monitor WBC count. Monitor liver function before and during course of therapy; evaluate ALT/SGPT every month for first 3 mo, every 3 mo for remainder of first year, and periodically thereafter.
  • Withhold drug and notify physician if liver enzymes are elevated.

Patient & Family Education

  • Do not increase dose. There is no increased benefit from daily doses >50 mg q12h.
  • Report any febrile illness to physician.
  • Do not drive or engage in potentially hazardous activities until response to drug is known.
  • Learn common adverse effects and possible adverse interaction with alcohol.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

© 2006-2023 Last Updated On: 01/27/2023 (0)
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