riluzole
amyotrophic lateral sclerosis
The disease presents in adulthood, usually between the ages of 40 and 70, and affects men two to three times more often than women. The initial symptom is weakness of skeletal muscles, especially in the limb. As the disease progresses the patient has difficulty swallowing and talking, with dyspnea as the accessory muscles of respiration are affected. Eventually muscles atrophy and the patient becomes a functional quadriplegic. Mentation is not affected, so that the patient remains alert and aware of functional loss and the inevitable outcome. Although there may be periods of remission, the disease usually progresses rapidly, with death in 2 to 5 years. The cause of ALS is not known and there is no cure. Treatment is intended to provide symptomatic relief, prevent complications, and maintain optimal function as long as possible.
Intervention is planned and implemented according to each patient's needs at specific times during the course of the illness. In general, the major problems encountered are those related to (1) dysphagia and the need to meet nutritional requirements and avoid aspiration, (2) dyspnea and maintenance of blood gases within normal range, (3) aphasia and impaired verbal communication, (4) weakness, impaired mobility, and activity intolerance, (5) constipation, (6) pain and discomfort due to muscle cramps, and (7) alteration in self-concept and body image.
The patient and family also will need assistance in managing home care, coping with the effects of the illness, and maintaining optimal functioning in the patient. Community health nurses and home health care professionals and paraprofessionals should be available to provide a variety of services including physical therapy, occupational therapy, social services, mental health care, and medical and nursing care.
A resource agency that can provide assistance and information to ALS patients and their families is the Amyotrophic Lateral Sclerosis Association, 21021 Ventura Blvd., Suite 321, Woodland Hills, CA 91364-2206, (800) 782–4747; http://www.alsa.org.
riluzole
Pharmacologic class: Glutamate antagonist
Therapeutic class: Amyotrophic lateral sclerosis (ALS) agent
Pregnancy risk category C
Action
Unknown. Thought to inhibit amino acid accumulation on motor neurons of CNS, improving nerve impulse transmission.
Availability
Tablets: 50 mg
Indications and dosages
➣ ALS
Adults: 50 mg P.O. q 12 hours
Off-label uses
• Cervical dystonia
• Huntington's disease
Contraindications
• Hypersensitivity to drug or its components
Precautions
Use cautiously in:
• hepatic or renal insufficiency, neutropenia, febrile illness
• elderly patients
• female patients and Japanese patients (may have decreased metabolic capacity to eliminate drug)
• pregnant or breastfeeding patients
• children.
Administration
• Give at least 1 hour before or 2 hours after a meal to maximize absorption.
Adverse reactions
CNS: headache, dizziness, drowsiness, asthenia, hypertonia, depression, insomnia, malaise, vertigo, circumoral paresthesia
CV: hypertension, orthostatic hypotension, tachycardia, palpitations, peripheral edema, phlebitis, cardiac arrest
EENT: rhinitis, sinusitis, oral candidiasis
GI: nausea, vomiting, diarrhea, abdominal pain, dyspepsia, flatulence, stomatitis, dry mouth, anorexia
GU: urinary tract infection, dysuria
Hematologic: neutropenia
Musculoskeletal: back pain, joint pain
Respiratory: decreased lung function, increased cough, pneumonia
Skin: pruritus, eczema, alopecia, exfoliative dermatitis
Other: tooth disorders, weight loss
Interactions
Drug-drug. Allopurinol, methyldopa, sulfasalazine: increased risk of hepatotoxicity
CYP450-1A2 inducers (such as omeprazole, rifampin): increased riluzole elimination
CYP450-1A2 inhibitors (such as amitriptyline, phenacetin, quinolones, theophylline): decreased riluzole elimination
Drug-diagnostic tests. Alanine aminotransferase, aspartate aminotransferase, bilirubin, gamma-glutamyltransferase: increased levels
Drug-food. High-fat foods: decreased riluzole absorption
Drug-behaviors. Alcohol use: increased risk of hepatotoxicity
Patient monitoring
• Monitor liver function tests and CBC.
• Assess vital signs and cardiovascular status, particularly for hypertension, orthostatic hypotension, and peripheral edema.
• Closely monitor respiratory status for decreased lung function and pneumonia.
• Monitor weight, nutritional status, and hydration.
• Closely monitor females and patients of Japanese origin, who are at increased risk for adverse reactions.
Patient teaching
• Tell patient to take 1 hour before or 2 hours after a meal, at same time each day.
• Instruct patient to take his temperature regularly and report fever.
See Teach patient to immediately report arm or leg swelling, difficulty breathing, and other signs of decreased lung function.
• Advise patient to minimize GI upset by eating small, frequent servings of food and drinking plenty of fluids.
• Caution patient to avoid high-fat foods and alcohol.
• Instruct patient to move slowly when sitting up or standing, to avoid dizziness from sudden blood pressure decrease.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and behaviors mentioned above.