RILUZOLE

Riluzole is a member of the benzothiazole class. The chemical designation for riluzole is 2-amino-6-(trifluoromethoxy) benzothiazole. Its molecular formula is C 8 H 5 F 3 N 2 OS, and its molecular weight is 234.2. The chemical structure is: Riluzole is a white to slightly yellow powder that is very soluble in dimethylformamide, dimethylsulfoxide, and methanol; freely soluble in dichloromethane; sparingly soluble in 0.1 N HCl; and very slightly soluble in water and in 0.1 N NaOH. Each film-coated tablet for oral use contains 50 mg of riluzole, USP and the following inactive ingredients: anhydrous dibasic calcium phosphate, colloidal silicon dioxide, croscarmellose sodium, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol 400, povidone, talc and titanium dioxide. structure

Riluzole tablets, USP are indicated for the treatment of amyotrophic lateral sclerosis (ALS). Riluzole is indicated for the treatment of amyotrophic lateral sclerosis (ALS) (1)

The recommended dosage for riluzole is 50 mg taken orally twice daily. Riluzole should be taken at least 1 hour before or 2 hours after a meal [ see Clinical Pharmacology (12.3)] . Measure serum aminotransferases before and during treatment with riluzole [ see Warnings and Precautions (5.1) ]. Recommended dosage: 50 mg twice daily, taken at least 1 hour before or 2 hours after a meal (2) Measure serum aminotransferases before and during treatment ( 2 , 5.1 )

Riluzole tablets are contraindicated in patients with a history of severe hypersensitivity reactions to riluzole or to any of its components (anaphylaxis has occurred) [ see Adverse Reactions (6.1) ] . Patients with a history of severe hypersensitivity reactions to riluzole or to any of its components (4)

The following adverse reactions are described below and elsewhere in the labeling: Hepatic Injury [ see Warnings and Precautions (5.1) ] Neutropenia [ see Warnings and Precautions (5.2) ] Interstitial lung disease [ see Warnings and Precautions (5.3) ] Most common adverse reactions (incidence greater than or equal to 5% and greater than placebo) were asthenia, nausea, dizziness, decreased lung function, and abdominal pain ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Sun Pharmaceutical Industries, Inc. at 1-800-818-4555 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 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 riluzole 50 mg twice daily [ see Clinical Studies (14) ] . The most common adverse reactions in the riluzole 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 riluzole 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 riluzole-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 Riluzole Tablets 50 mg twice daily (N=313) Placebo (N=320) 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% 6.2 Postmarketing Experience The following adverse reactions have been identified during postapproval use of riluzole. 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. Acute hepatitis and icteric toxic hepatitis [ see Warnings and Precautions (5.1) ] Renal tubular impairment Pancreatitis

Strong to moderate CYP1A2 inhibitors: Coadministration may increase riluzole-associated adverse reactions (7.1) Strong to moderate CYP1A2 inducers: Coadministration may result in decreased efficacy (7.2) Hepatotoxic drugs: Riluzole-treated patients that take other hepatotoxic drugs may be at increased risk for hepatotoxicity (7.3) 7.1 Agents that may Increase Riluzole Blood Concentrations CYP1A2 inhibitors Coadministration of riluzole (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 riluzole may increase the risk of riluzole-associated adverse reactions [ see Clinical Pharmacology (12.3) ] . 7.2 Agents that may Decrease Riluzole Plasma Concentrations CYP1A2 inducers Coadministration of riluzole (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 (12.3) ] . 7.3 Hepatotoxic Drugs Clinical trials in ALS patients excluded patients on concomitant medications which were potentially hepatotoxic (e.g., allopurinol, methyldopa, sulfasalazine). Riluzole-treated patients who take other hepatotoxic drugs may be at an increased risk for hepatotoxicity [ see Warnings and Precautions (5.1) ] .