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Side Effects


The following adverse reactions are described below and elsewhere in the labeling:

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Adverse Reactions In Controlled Clinical Trials

In the placebo-controlled clinical trials in patients with ALS (Study 1 and 2), a total of 313 patients received RILUTEK 50 mg twice daily [see Clinical Studies]. The most common adverse reactions in the RILUTEK group (in at least 5% of patients and more frequently than in the placebo group) were asthenia, nausea, dizziness, decreased lung function, and abdominal pain. The most common adverse reactions leading to discontinuation in the RILUTEK group were nausea, abdominal pain, constipation, and elevated ALT.

There was no difference in rates of adverse reactions leading to discontinuation in females and males. However, the incidence of dizziness was higher in females (11%) than in males (4%). The adverse reaction profile was similar in older and younger patients. There were insufficient data to determine if there were differences in the adverse reaction profile in different races.

Table 1 lists adverse reactions that occurred in at least 2% of RILUTEK-treated patients (50 mg twice daily) in pooled Study 1 and 2, and at a higher rate than placebo.

Table 1: Adverse Reactions in Pooled Placebo-Controlled Trials (Studies 1 and 2) in Patients with ALS

  RILUTEK 50 mg twice daily
Asthenia 19% 12%
Nausea 16% 11%
Decreased lung function 10% 9%
Hypertension 5% 4%
Abdominal pain 5% 4%
Vomiting 4% 2%
Arthralgia 4% 3%
Dizziness 4% 3%
Dry mouth 4% 3%
Insomnia 4% 3%
Pruritus 4% 3%
Tachycardia 3% 1%
Flatulence 3% 2%
Increased cough 3% 2%
Peripheral edema 3% 2%
Urinary Tract Infection 3% 2%
Circumoral paresthesia 2% 0%
Somnolence 2% 1%
Vertigo 2% 1%
Eczema 2% 1%

Postmarketing Experience

The following adverse reactions have been identified during postapproval use of RILUTEK. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Read the Rilutek (riluzole) Side Effects Center for a complete guide to possible side effects


Agents That May Increase Riluzole Blood Concentrations

CYP1A2 inhibitors

Co-administration of RILUTEK (a CYP1A substrate) with CYP1A2 inhibitors was not evaluated in a clinical trial; however, in vitro findings suggest an increase in riluzole exposure is likely. The concomitant use of strong or moderate CYP1A2 inhibitors (e.g., ciprofloxacin, enoxacin, fluvoxamine, methoxsalen, mexiletine, oral contraceptives, thiabendazole, vemurafenib, zileuton) with RILUTEK may increase the risk of RILUTEK-associated adverse reactions [see CLINICAL PHARMACOLOGY].

Agents That May Decrease Riluzole Plasma Concentrations

CYP1A2 inducers

Co-administration of RILUTEK (a CYP1A substrate) with CYP1A2 inducers was not evaluated in a clinical trial; however, in vitro findings suggest a decrease in riluzole exposure is likely. Lower exposures may result in decreased efficacy [see CLINICAL PHARMACOLOGY].

Hepatotoxic Drugs

Clinical trials in ALS patients excluded patients on concomitant medications which were potentially hepatotoxic (e.g., allopurinol, methyldopa, sulfasalazine). RILUTEK-treated patients who take other hepatotoxic drugs may be at an increased risk for hepatotoxicity [see WARNINGS AND PRECAUTIONS].

Read the Rilutek Drug Interactions Center for a complete guide to possible interactions

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 6/7/2016

Side Effects

Rilutek - User Reviews

Rilutek User Reviews

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Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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