Zonisamide

INTRODUCTION

Indications

Partial seizures in adults.

Action

Raises the threshold for seizures and reduces duration of seizures, probably by action on sodium and calcium channels. Therapeutic Effects: ↓ frequency of partial seizures.

Adverse Reactions/Side Effects

CNS: drowsiness, fatigue, agitation/irritability, depression, dizziness, psychomotor slowing, psychosis, weakness. EENT: amblyopia, tinnitus. Resp: cough, pharyngitis. GI: anorexia, nausea, vomiting. GU: kidney stones. Derm: oligohidrosis (↑ in children), rash. Metab: hyperthermia (↑ in children). Neuro: abnormal gait, hyperesthesia, incoordination, tremor. Misc: ALLERGIC REACTIONS, INCLUDING STEVENS-JOHNSON SYNDROME.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Monitor allergic responses, including skin reactions such as rash, itching/burning skin, hives, exfoliation, and dermatitis. Notify physician immediately about because certain skin reactions may indicate serious hypersensitivity reactions (Stevens-Johnson syndrome).

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

• Assess dizziness 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.

• Monitor daytime drowsiness, agitation, irritability, depression, psychosis, or other psychiatric disturbances. Repeated or excessive symptoms may require change in dose or medication.

• Assess any gait disturbances, incoordination, tremor, or increased sensation to pain/touch to rule out neuromuscular pathology; that is, try to determine if neurologic signs are drug induced rather than caused by neurologic pathology.

• Monitor and report signs of kidney stones, including severe pain in the side and back, pain on urination, bloody urine, and a persistent urge to urinate.

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 effects.

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

• Advise patient about the risk of daytime drowsiness and decreased attention and mental focus. Use care if driving or in other activities that require strong concentration and fast responses.

• Instruct patient and family/caregivers to report other troublesome side effects such as severe or prolonged cough, pharyngeal irritation, vision problems, ringing/buzzing in the ears (tinnitus), skin reactions (rash, inadequate sweating), or GI problems (nausea, vomiting, loss of appetite).

Pharmacokinetics

Absorption: Well absorbed following oral administration.

Distribution: Binds extensively to red blood cells.

Metabolism ...