riluzole (Rilutek)

Indications

• amyotrophic lateral sclerosis (ALS)
• Huntington's disease

Dosage

• 50 mg PO every 12 hours
• no increased benefits fromm larger amounts
• take at same time each day, 1 hour before or 2 hours after meals

Tabs: 50 mg. Dosage adjustment with hepatic impairment.

Avoid excessive alcohol.

Pharmacokinetics

• metabolized in the liver by cyt P450 1A2

elimination via liver

elimination via kidney

Monitor

• liver function tests (serum AST, serum ALT, serum bilirubin, serum GGT) baseline
• serum transaminases (serum AST, serum ALT)
  • monthly for 1st 3 months
  • every 3 months for remainder of 1st year
  • periodically thereafter
• complete blood count (CBC)

Adverse effects

• common (> 10%)
  • nausea, abdominal pain, constipation, elevation of serum alanine aminotransferase (ALT)

Drug interactions

• drugs that induce cyt P450 1A2 reduce effect of riluzole
  • cigarette smoke
  • charbroiled foods
  • rifampin
  • omeprazole
• inhibitors of cyt P450 1A2 increase toxicity of riluzole
  • caffeine
  • theophylline
  • amitriptyline
  • quinolones

Mechanism of action

• antiglutamate activity; inhibits release of glutamate
• may slow the progression of amyotrophic lateral sclerosis
  • benefit primarily in patients with bulbar-onset disease
  • effectiveness in patients with limb-girdle disease is uncertain

More general terms

• miscellaneous pharmacologic agent

Additional terms

• amyotrophic lateral sclerosis (ALS); Lou Gerig's disease
• cytochrome p450 1A2 (cytochrome P3-450, phenacetin deethylase, cytochrome p450-4, CYP1A2)

Database

• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5070