Lacosamide

INTRODUCTION

Indications

Adjunctive therapy of partial-onset seizures.

Action

Mechanism is not known, but may involve enhancement of slow inactivation of sodium channels with resultant membrane stabilization; also binds to collapsin response mediator protein-2 (CRMP-2) which is involved in neural differentiation and growth. Therapeutic Effects: Decreased incidence and severity of partial-onset seizures.

Adverse Reactions/Side Effects

CNS: dizziness, headache, syncope, vertigo. EENT: diplopia. CV: PR interval prolongation. GI: nausea, vomiting. Neuro: ataxia. Misc: multiorgan hypersensitivity reactions (Drug Reaction with eosinophilia and systemic symptoms—DRESS).

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Be alert for hypersensitivity responses that might indicate DRESS. These responses include fever, skin reactions (rash that progresses to exfoliative dermatitis), blood dyscrasias (eosinophilia, neutrophilia, neutropenia, thrombopenia, anemia), and involvement of one or more internal organs leading to hepatitis, pneumonitis, nephritis, myocarditis, pericarditis, myositis, pancreatitis, or thyroiditis. Notify physician of these reactions immediately.

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

• Assess dizziness, syncope, and vertigo that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician, and caution the patient and family/caregivers to guard against falls and trauma.

• Assess any ataxia or gait disturbances to rule out neuromuscular pathology; that is, try to determine if neurologic signs are drug-induced rather than caused by neurologic pathology.

• Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendixes G, H). Report any rhythm disturbances (prolonged PR interval) or symptoms of increased arrhythmias, including palpitations, chest discomfort, shortness of breath, fainting, and fatigue/weakness.

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).

• Because of the risk of cardiac arrhythmias (prolonged PR interval), use caution during aerobic exercise and other forms of therapeutic exercise. Assess exercise tolerance frequently (blood pressure, heart rate, fatigue levels), and terminate exercise immediately if any untoward responses occur (See Appendix L).

Patient/Client-Related Instruction

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

• Advise patients on prolonged antiseizure therapy not to discontinue medication without consulting their physician. Abrupt withdrawal may cause increased seizures.

• Instruct patient and family/caregivers to report other troublesome side effects such as severe or prolonged vision problems or GI reactions problems (nausea, vomiting).

Pharmacokinetics

Absorption: 100% absorbed following oral administration; IV administration results in complete bioavailability.