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Pharmacologic class: Benzodiazepine
Therapeutic class: Anticonvulsant
Controlled substance schedule IV
Pregnancy risk category D
Unknown. May enhance activity of gamma-aminobutyric acid, an inhibitory neurotransmitter in CNS.
Tablets: 0.5 mg, 1 mg, 2 mg
Indications and dosages
➣ Absence seizures (Lennox-Gastaut syndrome); akinetic and myoclonic seizures
Adults: Initially, 1.5 mg/day P.O. in three divided doses; may increase by 0.5 to 1 mg q 3 days until seizures are adequately controlled or drug intolerance occurs. Maximum dosage is 20 mg/day.
Infants and children ages 10 and younger or weighing 30 kg (66 lb) or
less: Initially, 0.01 to 0.03 mg/kg/day P.O. Give total dosage (not to exceed 0.05 mg/kg/day) in two to three equally divided doses. Increase by no more than 0.25 to 0.5 mg q 3 days until dosage of 0.1 to 0.2 mg/kg/day is reached, seizures are adequately controlled, or drug intolerance occurs.
• Acute manic episodes of bipolar disorder
• Multifocal tic disorders
• Parkinsonian dysarthria
• Periodic leg movements occurring during sleep
• Adjunctive treatment of schizophrenia
• Hypersensitivity to drug or other benzodiazepines
• Severe hepatic disease
• Acute angle-closure glaucoma
Use cautiously in:
• renal impairment, chronic respiratory disease, open-angle glaucoma
• history of porphyria
• pregnant or breastfeeding patients
☞ Be aware that overdose may cause fatal respiratory depression or cardiovascular collapse.
• Give tablets with water, and make sure patient swallows them whole.
CNS: ataxia, fatigue, drowsiness, behavioral changes, depression, dizziness, nervousness, reduced intellectual ability
EENT: abnormal eye movements, blurred vision, diplopia, nystagmus, sinusitis, rhinitis, pharyngitis
GI: constipation, diarrhea, hypersalivation
GU: dysuria, nocturia, urinary retention, dysmenorrhea, delayed ejaculation, erectile dysfunction
Hematologic: anemia, eosinophilia,
Respiratory: increased respiratory secretions, upper respiratory tract infection, cough, bronchitis, respiratory depression
Other: appetite changes, fever, physical or psychological drug dependence, drug tolerance, allergic reaction
Drug-drug. Antidepressants, antihistamines, opioids, other benzodiazepines: additive CNS depression
Barbiturates, rifampin: increased metabolism and decreased efficacy of clonazepam
Cimetidine, disulfiram, fluoxetine, hormonal contraceptives, isoniazid, ketoconazole, metoprolol, propoxyphene, propranolol, valproic acid: decreased clonazepam metabolism
Phenytoin: decreased clonazepam blood level
Drug-diagnostic tests. Eosinophils, liver function tests: increased values
Platelets, white blood cells: decreased counts
Drug-herbs. Chamomile, hops, kava, skullcap, valerian: increased CNS depression
Drug-behaviors. Alcohol use: increased CNS depression
• Monitor patient for respiratory depression. Assess respiratory rate and quality, oxygen saturation (using pulse oximetry), and mental status.
• Monitor hematologic and liver function test results.
☞ Instruct patient to immediately report easy bleeding or bruising or yellowing of skin or eyes.
• Advise patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
☞ Caution patient not to stop taking drug abruptly. Advise him to consult prescriber for dosage-tapering schedule if he wishes to discontinue drug.
• Advise patient not to drink alcohol, which may increase drowsiness, dizziness, and risk of seizures.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.
- Petit mal,
- Myoclonic seizures.
Time/action profile (anticonvulsant activity)
|PO||20–60 min||1–2 hr||6–12 hr|
Adverse Reactions/Side Effects
Central nervous system
- suicidal thoughts (life-threatening)
- behavioral changes (most frequent)
- drowsiness (most frequent)
- slurred speech
- abnormal eye movements
- ↑ secretions
- weight gain
- urinary retention
- ataxia (most frequent)
- physical dependence
- psychological dependence
Drug-Drug interactionAlcohol, antidepressants, antihistamines, other benzodiazepines, and opioid analgesics ; concurrent use results in ↑ CNS depression.Cimetidine, hormonal contraceptives, disulfiram, fluoxetine, isoniazid, ketoconazole, metoprolol, propranolol, or valproic acid may ↓ metabolism and ↑ toxicity of clonazepam.May ↓ efficacy of levodopa.Rifampin or barbiturates may ↑ metabolism and ↓ effectiveness.Sedative effects may be ↓ by theophylline.May ↑ serum phenytoin levels.Phenytoin may ↓ levels.Concomitant use of kava-kava, valerian, or chamomile can ↑ CNS depression.
Availability (generic available)
- Observe and record intensity, duration, and location of seizure activity.
- Assess degree and manifestations of anxiety and mental status (orientation, mood, behavior) prior to and periodically during therapy.
- Assess need for continued treatment regularly.
- Assess patient for drowsiness, unsteadiness, and clumsiness. These symptoms are dose related and most severe during initial therapy; may decrease in severity or disappear with continued or long-term therapy.
- Monitor closely for notable changes in behavior that could indicate the emergence or worsening of suicidal thoughts or behavior or depression.
- Lab Test Considerations: Patients on prolonged therapy should have CBC and liver function test results evaluated periodically. May cause an ↑ in serum bilirubin, AST, and ALT.
Therapeutic serum concentrations are 20–80 mg/mL. Flumazenil antagonizes clonazepam toxicity or overdose (may induce seizures in patients with history of seizure disorder or who are on tricyclic antidepressants).
- May cause ↓ thyroidal uptake of sodium iodide, 123I, and 131I.
Potential Nursing DiagnosesRisk for injury (Indications, Side Effects)
- Do not confuse clonazepam with clonidine, clozapine, clorazepate, or lorazepam. Do not confuse Klonopin with clonidine.
- Institute seizure precautions for patients on initial therapy or undergoing dose manipulations.
- Oral: Administer with food to minimize gastric irritation. Tablets may be crushed if patient has difficulty swallowing. Administer largest dose at bedtime to avoid daytime sedation. Taper by 0.25 mg every 3 days to decrease signs and symptoms of withdrawal. Some patients may require longer taper period (months).
- Orally disintegrating tablets should be left in the package until use. Remove from the blister pouch. Do not push tablet through the blister; peel open the blister pack with dry hands and place tablet on tongue. Tablet will dissolve rapidly and be swallowed with saliva. No liquid is needed to take the orally disintegrating tablet.
- Instruct patient to take medication exactly as directed. Take missed doses within 1 hr or omit; do not double doses. Abrupt withdrawal of clonazepam may cause status epilepticus, tremors, nausea, vomiting, and abdominal and muscle cramps. Instruct patient to read the Medication Guide before starting and with each Rx refill, changes may occur.
- Advise patient that clonazepam is usually prescribed for short-term use and does not cure underlying problems.
- Advise patient to not share medication with others.
- May cause drowsiness or dizziness. Advise patient to avoid driving or other activities requiring alertness until response to drug is known.
- Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care professional before taking any other Rx, OTC, or herbal products. Caution patient to avoid taking alcohol or other CNS depressants concurrently with this medication.
- Advise patient to notify health care professional of medication regimen prior to treatment or surgery.
- Instruct patient and family to notify health care professional of unusual tiredness, bleeding, sore throat, fever, clay-colored stools, yellowing of skin, or behavioral changes. Advise patient and family to notify health care professional if thoughts about suicide or dying, attempts to commit suicide; new or worse depression; new or worse anxiety; feeling very agitated or restless; panic attacks; trouble sleeping; new or worse irritability; acting aggressive; being angry or violent; acting on dangerous impulses; an extreme increase in activity and talking; other unusual changes in behavior or mood occur.
- Advise female patients to notify health care professional if pregnancy is planned or suspected or if breast feeding. Encourage pregnant patients to enroll in North American Antiepileptic Drug (NAAED) Pregnancy Registry to collect information about safety of antiepileptic drugs during pregnancy. To enroll, patients can call 1-888-233-2334.
- Patient on anticonvulsant therapy should carry identification at all times describing disease process and medication regimen.
- Emphasize the importance of follow-up exams to determine effectiveness of the medication.
- Decrease or cessation of seizure activity without undue sedation. Dose adjustments may be required after several months of therapy.
- Decrease in frequency and severity of panic attacks.
- Relief of leg movements during sleep.
- Decrease in pain from neuralgia.