Riluzole

Indications

Riluzole is used for: Amyotrophic lateral sclerosis

Adult Dose

Oral Amyotrophic lateral sclerosis Adult: 50 mg bid. Discontinue if ALT levels increase to 5 times the upper limit of normal (ULN). Hepatic impairment Mild or moderate (Child-Pugh A or B): Patients had increases in AUC; thus, may be at increased risk of adverse reactions Severe (Child-Pugh C): Unknown Not recommended for patients with baseline serum aminotransferases (AST/ALTs) >5x ULN or evidence of liver dysfunction (eg, elevated bilirubin)

Child Dose

Renal Dose

Administration

Should be taken on an empty stomach. Take on an empty stomach at least 1 hr before or 2 hr after meals.

Contra Indications

Hepatic impairment (baseline transaminases >3 times the upper limit of normal).

Precautions

Patient with history of liver diseases. Pregnancy and lactation. Patient Counselling This drug may cause dizziness, drowsiness or vertigo, if affected, do not drive or operate machinery. Monitoring Parameters Monitor serum aminotransferase concentrations (e.g. ALT) before and during therapy; signs and symptoms of hepatic injury.

Pregnancy-Lactation

Pregnancy There are no studies in pregnant women, and case reports have been inadequate to inform of drug-associated risk Unknown if risk of major birth defects and miscarriage in patients with amyotrophic lateral sclerosis Animal data In studies in which riluzole was orally administered to pregnant animals, developmental toxicity (decreased embryofetal/offspring viability, growth, and functional development) was observed at clinically relevant doses Based on these results, advise women of possible risks to fetus associated with use of riluzole during pregnancy In rats, oral administration of riluzole resulted in decreased fertility indices and increases in embryo lethality Lactation Unknown if distributed in human breast milk

Interactions

Decreased rate of elimination with CYP1A2 inhibitors (e.g. caffeine, ciprofloxacin, oral contraceptives). Increased rate of elimination with CYP1A2 inducers (e.g. rifampicin, omeprazole). Increased risk of hepatotoxicity with hepatotoxic drugs (e.g. allopurinol, methyldopa, sulfasalazine).

Side Effects

Side effects of Riluzole : >10% Oral hypoesthesia (29%) Asthenia (19%) Nausea (16%) 1-10% Decreased lung function (10%) Hypertension (5%) Abdominal pain (5%) Vomiting (4%) Arthralgia (4%) Dizziness (4%) Dry mouth (4%) Insomnia (4%) Pruritus (4%) Tachycardia (3%) Flatulence (3%) Increased cough (3%) Peripheral edema (3%) Urinary tract infection (3%) Circumoral paresthesia (2%) Somnolence (2%) Vertigo (2%) Eczema (2%)

Mode of Action

Riluzole is a glutamate inhibitor used to slow disease progression and prolong survival rate in patients with amyotrophic lateral sclerosis. The exact mechanism of its action is not fully elucidated but is shown to inhibit the release of glutamate, inactivate voltage-dependent Na channels, and interfere with intracellular events following binding of transmitter at excitatory amino acid receptors.