Vigabatrin

INTRODUCTION

Indications

Management (adjunctive) of refractory complex partial seizures in adults in patients who have responded inadequately to several alternative treatments; not a 1st-line treatment. Management of infantile spasms (ISs) in patients 1 mo–2 yr.

Action

Acts an irreversible inhibitor of γ-aminobutyric acid transaminase (GABA-T), the enzyme responsible for the metabolism of the inhibitory neurotransmitter GABA. This action results in increased levels of GABA in the central nervous system. Therapeutic Effects: ↓ incidence and severity of refractory complex partial seizures.

Adverse Reactions/Side Effects

CNS: SUICIDAL THOUGHTS, confusional state, memory impairment, drowsiness, fatigue. CV: edema. EENT: blurred vision, nystagmus, vision loss. Hemat: anemia. Metab: weight gain. MS: arthralgia. Neuro: abnormal coordination, tremor, peripheral neuropathy.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Be alert for suicidal thoughts and ideology; notify physician immediately if patient expresses suicidal thoughts or exhibits suicidal behaviors.

• Document the number, duration, and severity of seizures to help determine if this drug is effective in reducing seizure activity.

• Assess incoordination and tremor that might affect gait, balance, and other functional activities. Report balance problems and functional limitations to the physician, and caution the patient and family/caregivers to guard against falls and trauma.

• Monitor signs of anemia, including unusual fatigue, shortness of breath with exertion, and bruising, and pale skin. Notify physician immediately if these signs occur.

• Assess signs of peripheral neuropathy such as numbness, tingling, and decreased muscle strength. Establish baseline electroneuromyographic values using EMG and nerve conduction at the beginning of drug treatment whenever possible, and reexamine these values periodically to document drug-induced changes in peripheral nerve function.

• Assess any joint pain to rule out musculoskeletal pathology; that is, try to determine if pain is drug induced rather than caused by anatomic or biomechanical problems.

• Monitor daytime drowsiness, confusion, hallucinations, memory impairment, or other changes in personality. Repeated or excessive symptoms may require change in dose or medication.

• Assess peripheral edema using girth measurements, volume displacement, and measurement of pitting edema (See Appendix N). Report increased swelling in feet and ankles or a sudden increase in body weight due to fluid retention.

• Periodically assess body weight and other anthropometric measures (body mass index, body composition). Report a rapid or unexplained weight gain.

Interventions

• Guard against falls and trauma (hip fractures, head injury, and so forth), especially if dizziness or ataxia affect gait and balance. Implement fall-prevention strategies, especially if balance is impaired (See Appendix E).

Patient/Client-Related Instruction

• Advise patient to avoid alcohol and other CNS depressants because of the increased risk of sedation and adverse ...