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(RIL yoo zole)

Index Terms

  • 2-Amino-6-Trifluoromethoxy-benzothiazole
  • RP-54274

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Tablet, Oral:

Rilutek: 50 mg

Generic: 50 mg

Brand Names: U.S.

  • Rilutek

Pharmacologic Category

  • Glutamate Inhibitor


Mechanism of action is not known. Pharmacologic properties include inhibitory effect on glutamate release, inactivation of voltage-dependent sodium channels; and ability to interfere with intracellular events that follow transmitter binding at excitatory amino acid receptors


High-fat meal decreases AUC by 20% and peak blood levels by 45%


Vd: ~3.4 L/kg


Hepatic via CYP1A2 and UGT-HP4


Urine (90%; 2% as unchanged drug) and feces (5%)

Half-Life Elimination

12 hours

Protein Binding

Plasma: 96%, primarily to albumin and lipoproteins

Special Populations: Hepatic Function Impairment

AUC increased by about 1.7- and 3-fold in patients with mild and moderate chronic hepatic insufficiency, respectively. The pharmacokinetics have not been studied in patients with severe hepatic impairment.

Special Populations: Gender

Mean clearance was found to be 30% lower in women compared with men.

Special Populations: Race

Clearance was 50% lower in male Japanese patients than in Caucasian patients.

Special Populations Note

Smoking: Clearance was 20% greater in smokers compared to nonsmokers.

Use: Labeled Indications

Amyotrophic lateral sclerosis: Treatment of patients with amyotrophic lateral sclerosis (ALS); may extend survival and/or time to tracheostomy


Hypersensitivity to riluzole or any component of the formulation

Canadian labeling: Additional contraindications (not in US labeling): Hepatic disease or baseline serum transaminases >3 times ULN; pregnancy; breast-feeding

Dosing: Adult

Amyotrophic lateral sclerosis (ALS): Oral: 50 mg twice daily.

Dosing: Geriatric

Refer to adult dosing.

Dosing: Renal Impairment

US labeling: There are no dosage adjustments provided in the manufacturer’s labeling.

Canadian labeling: Use is not recommended in patients with renal impairment (has not been studied).

Dosing: Hepatic Impairment

There are no dosage adjustments provided in the manufacturer’s labeling; use with caution.


Oral: Administer at the same time each day, at least 1 hour before or 2 hours after a meal.


Store at 20°C to 25°C (68°F to 77°F). Protect from bright light.

Drug Interactions

Cannabis: May decrease the serum concentration of CYP1A2 Substrates. Monitor therapy

CYP1A2 Inducers (Strong): May increase the metabolism of CYP1A2 Substrates. Management: Consider an alternative for one of the interacting drugs. Some combinations may be specifically contraindicated. Consult appropriate manufacturer labeling. Consider therapy modification

Cyproterone: May decrease the serum concentration of CYP1A2 Substrates. Monitor therapy

Teriflunomide: May decrease the serum concentration of CYP1A2 Substrates. Monitor therapy

Adverse Reactions


Gastrointestinal: Nausea (16%)

Neuromuscular & skeletal: Weakness (19%)

1% to 10%:

Cardiovascular: Hypertension (5%), peripheral edema (3%), tachycardia (3%)

Central nervous system: Dizziness (4%), somnolence (2%), vertigo (2%), malaise (1%)

Dermatologic: Pruritus (4%), eczema (2%), exfoliative dermatitis (1%)

Gastrointestinal: Abdominal pain (5%), vomiting (4%), flatulence (3%), oral moniliasis (1%), stomatitis (1%), tooth caries (1%)

Genitourinary: Urinary tract infection (3%), dysuria (1%)

Hepatic: Liver function tests increased (8% >3 x ULN; 2% >5 x ULN)

Neuromuscular & skeletal: Arthralgia (4%), paresthesia (circumoral; 2%), tremor (1%)

Respiratory: Lung function decreased (10%), cough increased (3%)

<1% (Limited to important or life-threatening): Alkaline phosphatase increased, amblyopia, anaphylactoid reaction, anaphylaxis, angioedema, aplastic anemia, arthrosis, asthma, ataxia, bone necrosis, bradycardia, bundle branch block, cataract, cerebral hemorrhage, deafness, dementia, diabetes mellitus, diabetes insipidus, edema, erythema multiforme, extrapyramidal syndrome, facial paralysis, gastrointestinal hemorrhage, gastrointestinal ulcer, GGT increased, glaucoma, hallucination, heart failure, hematemesis, hematuria, hemoptysis, hepatitis, hypercalcemia, hypokalemia, hypokinesia, hyponatremia, hypotension, hypersensitivity pneumonitis, interstitial lung disease, jaundice, LDH increased, leukocytosis, leukopenia, lymphadenopathy, mania, myoclonus, neutropenia, osteoporosis, pancreatitis, peripheral neuritis, pleural effusion, pseudomembranous colitis, purpura, respiratory acidosis, seizure, subarachnoid hemorrhage, thrombosis, urinary retention, urticaria, uterine hemorrhage, ventricular fibrillation, ventricular tachycardia


Concerns related to adverse effects:

• CNS depression: May cause dizziness or somnolence; caution should be used performing tasks which require alertness (operating machinery or driving).

• Hepatic effects: May cause drug-induced hepatic injury (including fatality); asymptomatic elevations of hepatic transaminases may also occur. Elevations of transaminases may occur within 3 months of use. Use is not recommended in patients who develop hepatic transaminases >5 times the upper limit of normal. Monitor for signs and symptoms of hepatic injury every month for the first 3 months and periodically thereafter; discontinue use if evidence of hepatic dysfunction occurs (eg, elevated bilirubin).

• Neutropenia: Severe neutropenia has been reported (ANC <500/mm3) within the first 2 months of therapy. Evaluate patients with febrile illnesses.

• Pulmonary disorders: Interstitial lung disease (ILD), including hypersensitivity pneumonitis, has occurred. Discontinue therapy immediately if ILD occurs.

Disease-related concerns:

• Hepatic impairment: Use with caution in patients with hepatic impairment; the Canadian labeling contraindicates use in patients with hepatic disease or with baseline serum transaminases >3 times ULN.

• Renal impairment: Canadian labeling does not recommended use in patients with renal impairment (has not been studied).

Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

• Females: Use with caution in females; clearance decreased.

Monitoring Parameters

Serum aminotransferases including ALT levels before and during therapy; signs and symptoms of hepatic injury every month for the first 3 months and periodically thereafter.

Pregnancy Considerations

Adverse events have been observed in animal reproduction studies. Use is contraindicated during pregnancy (Canadian labeling).

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience nausea, loss of strength and energy, or abdominal pain. Have patient report immediately to prescriber signs of infection, signs of a severe pulmonary disorder (lung or breathing problems like trouble breathing, shortness of breath, or a cough that is new or worse), signs of liver problems (dark urine, feeling tired, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or yellow skin or eyes), severe dizziness, passing out, vision changes, severe headache, tachycardia, or swelling of arms or legs (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.