General

Pronunciation
toe-PEER-i-mate

Trade Name(s)

• Topamax

Pregnancy Category
Category C

Ther. class.
anticonvulsants
mood stabilizers

Indications

• Seizures including

» partial-onset

» primary generalized tonic-clonic

» seizures due to Lennox-Gastaut syndrome

• Prevention of migraine headache in adults

Unlabelled Use(s):
Adjunct in treatment of bipolar disorder

Action

Action may be due to

» Blockade of sodium channels in neurons

» Enhancement of gamma-aminobutyrate (GABA), an inhibitory neurotransmitter

» Prevention of activation of excitatory receptors

Therapeutic Effect(s):

• Decreased incidence of seizures

• Decreased incidence/severity of migraine headache

Pharmacokinetics

Absorption: Well absorbed (80%) after oral administration

Distribution: Unknown

Metabolism and Excretion: 70% excreted unchanged in urine

Half-life: 21 hr

TIME/ACTION PROFILE (blood levels†)

ROUTE	ONSET	PEAK	DURATION
PO	unknown	2 hr	12 hr

†After single dose

Contraindication/Precautions

Contraindicated in:

• Hypersensitivity

• Lactation

Use Cautiously in:

• Renal impairment (dosage reduction recommended if CCr <70 ml/min/1.73 m²)

• Hepatic impairment

• Dehydration

• OB: Use only if maternal benefit outweighs fetal risk

• Lactation: Discontinue drug or bottle feed.

• Pedi: Children are more prone to oligohydrosis and hyperthermia; safety in children <2 yr not established

• Geri: Consider age-related decrease in renal/hepatic impairment, concurrent disease states and drug therapy

Adverse Reactions/Side Effects

CNS: INCREASED SEIZURES, dizziness, drowsiness, fatigue, impaired concentration/memory, nervousness, psychomotor slowing, speech problems, sedation, aggressive reaction, agitation, anxiety, cognitive disorders, confusion, depression, malaise, mood problems.

EENT: abnormal vision, diplopia, nystagmus, acute myopia/secondary angle closure glaucoma,.

GI: nausea, abdominal pain, anorexia, constipation, dry mouth.

GU: kidney stones.

Derm: oligohydrosis ( in children).

F and E: hyperchloremic metabolic acidosis.

Hemat: leukopenia.

Metabolic: weight loss, hyperthermia( in children).

Neuro: ataxia, paresthesia, tremor.

Misc: SUICIDE ATTEMPT, fever.

*CAPITALS indicates life-threatening.
*italic indicates most frequent.

Interactions

Drug-Drug

• Blood levels and effects may be by phenytoin, carbamazepine, or valproic acid

• May blood levels and effects of phenytoin or amitriptyline

• May blood levels and effects of hormonal contraceptives, risperidone, lithium or valproic acid

• risk of CNS depression with alcohol or other CNS depressants

• Carbonic anhydrase inhibitors (acetazolamide) may risk of kidney stones

• Concurrent use with valproic acid may risk of hyperammonemia/encephalopathy

Route/Dosage

Epilepsy (monotherapy)

• PO (Adults and children >=10 yr):
Seizures/migraine prevention —50 mg/day initially, gradually increased over 6 wk to 400 mg/day in two divided doses.

Epilepsy (adjunctive therapy)

• PO (Adults and Children >= 17 yr): 25–50 mg/day increased by 25–50 mg/day at weekly intervals up to 200–400 mg/day in two divided doses (200–400 mg/day in two divided doses for partial seizures and 400 mg/dy in two divided doses for primary generalized tonic/clonic seizures.

Renal Impairment

• PO (Adults):
CCr<70 ml/min—50% of the usual dose.

• PO (Children 2–17 yr):
Seizures—5–9 mg/kg/day in 2 divided doses; initiate with 25 mg (or less based in 1–3 mg/kg) nightly for 7 days then increase at 1–2 wk intervals in increments of 1–3 mg/kg/day in 2 divided doses; titration should be based on clinical outcome.

Migraine prevention

• PO (Adults): 25 mg at night initially, increase by 25 mg/day at weekly intervals up to target dose of 100 mg/day in 2 divided doses.

Availability

• Sprinkle capsules: 15 mg, 25 mg

» Cost: 15 mg $114.19/60, 25 mg $139.96/60.

• Tablets: 25 mg, 50 mg, 100 mg, 200 mg

» Cost: 25 mg $369.90/180, 50 mg $703.96/180, 100 mg $1,023.97/180, 200 mg $1,162.91/180.

Assessment

Seizures

• Assess location, duration, and characteristics of seizure activity

Migraines

• Assess pain location, intensity, duration, and associated symptoms (photophobia, phonophobia, nausea, vomiting) during migraine attack. Monitor frequency and intensity of pain on pain scale

Bipolar disorder

• Administer Young Mania Rating Scale (YMRS) or similar tool to evaluate manic symptoms at baseline and over time in patients

Lab Test Considerations

• Monitor CBC with differential and platelet count before therapy to determine baseline levels and periodically during therapy. Frequently causes anemia

» Hepatic function should be monitored periodically throughout therapy. May cause AST and ALT levels

» Evaluate serum bicarbonate prior to and periodically during therapy. If metabolic acidosis occurs, dosing taper or discontinuation may be necessary

Potential Nursing Diagnoses

• Risk for injury (Indications)(Side Effects)

• Disturbed thought process (Indications)

Implementation

• Implement seizure precautions

» Do not confuse Topamax (topiramate) with Toprolol (metoprolol)

• PO: May be administered without regard to meals

» Do not break/crush tablets because of bitter taste

» Contents of the sprinkle capsules can be sprinkled on a small amount (teaspoon) of soft food, such as applesauce, custard, ice cream, oatmeal, pudding, or yogurt. To open, hold the capsule upright so that you can read the word "TOP." Carefully twist off the clear portion of the capsule. It may be best to do this over the small portion of the food onto which you will be pouring the sprinkles. Sprinkle the entire contents of the capsule onto the food. Be sure the patient swallows the entire spoonful of the sprinkle/food mixture immediately without chewing. Follow with fluids immediately to make sure all of the mixture is swallowed. Never store a sprinkle/food mixture for use at another time

Patient/Family Teaching

• Instruct patient to take topiramate exactly as directed. Take missed doses as soon as possible but not just before next dose; do not double doses. Notify health care professional if more than 1 dose is missed. Medication should be gradually discontinued to prevent seizures and status epilepticus

• May cause decreased sweating and increased body temperature. Advise patients, especially parents of pediatric patients, to provide adequate hydration and monitoring, especially during hot weather

• May cause dizziness, drowsiness, confusion, and difficulty concentrating. Caution patients to avoid driving or other activities requiring alertness until response to medication is known

• Advise patient to maintain a fluid intake of 2000–3000 ml of fluid/day to prevent the formation of kidney stones

• Instruct patient to notify health care professional immediately if periorbital pain or blurred vision occur. Medication should be discontinued if ocular symptoms occur. May lead to permanent loss of vision

• Caution patient to make position changes slowly to minimize orthostatic hypotension

• Advise patient not to take alcohol or other CNS depressants concurrently with this medication

• Advise patient to use a nonhormonal form of contraception while taking topiramate

• Instruct patient to notify health care professional of medication regimen before treatment or surgery

• Advise patient to use sunscreen and wear protective clothing to prevent photosensitivity reactions

• Advise patient to carry identification describing disease and medication regimen at all times

• Refer patient/family to Manic-Depressive and Depressive Association for support

Evaluation/Desired Outcomes

• Absence or reduction of seizure activity

• Decrease in incidence and severity of migraine headaches

• Remission of manic symptoms

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