CLONAZEPAM

CLONAZEPAM (kloe-na'zi-pam) Klonopin, Klonopin Wafers, Rivotril  Classifications: anticonvulsant; benzodiazepine; Therapeutic: anticonvulsant Prototype: Diazepam Pregnancy Category: D Controlled Substance: Schedule IV

Availability

0.5 mg, 1 mg, 2 mg tablets; 0.125 mg, 0.25 mg, 0.5 mg, 1 mg, and 2 mg orally disintegrating wafers

Action

BENZODIAZEPINE derivative with strong anticonvulsant activity and several other pharmacologic properties. It prevents seizures by potentiation of the effects of GABA, an inhibitory neurotransmitter. Suppresses the spread of seizure activity in the cortex, thalamus, and limbic regions of the brain.

Therapeutic Effect

Suppresses spike and wave discharge in absence seizures (petit mal) and decreases amplitude, frequency, duration, and spread of discharge in minor motor seizures.

Uses

Alone or with other drugs in absence, myoclonic, and akinetic seizures, Lennox-Gastaut syndrome, absence seizures refractory to succinimides or valproic acid, and for infantile spasms and restless legs.

Unlabeled Uses

Panic disorder, complex partial seizure pattern, and generalized tonic-clonic convulsions.

Contraindications

Hypersensitivity to benzodiazepines; liver disease; acute narrow-angle glaucoma; pulumonary disease, COPD; coma or CNS depression; pregnancy (category D), lactation; children <10 y.

Cautious Use

Renal or hepatic disease; COPD; drug-controlled open-angle glaucoma; bipolar disorder, preexisting depression; addiction-prone individuals; neuromuscular disease; children (because of unknown consequences of long-term use on growth and development); patient with mixed seizure disorders.

Route & Dosage

Seizures Adult: PO 1.5 mg/d in 3 divided doses, increased by 0.5–1 mg q3d until seizures are controlled or until intolerable adverse effects (max recommended dose: 20 mg/d) Child (<10 y): PO 0.01–0.03 mg/kg/d (not to exceed 0.05 mg/kg/d) in 3 divided doses; may increase by 0.25–0.5 mg q3d until seizures are controlled or until intolerable adverse effects (max recommended dose: 0.2 mg/kg/d) Panic Disorders Adult: PO 1–2 mg/d in divided doses (max: 4 mg/d)

Administration

Oral

• Give largest dose at bedtime if daily dose cannot be equally divided.
• Place wafer form on tongue to dissolve.
• If clonazepam is to replace a different anticonvulsant, verify whether or not the prior drug should be gradually tapered.
• Store in tightly closed container protected from light at 15°–30° C (59°–86° F) unless otherwise specified.

Adverse Effects (≥1%)

CV: Palpitations. GI: Dry mouth, sore gums, anorexia, coated tongue, increased salivation, increased appetite, nausea, constipation, diarrhea. Hematologic: Anemia, leukopenia, thrombocytopenia, eosinophilia. CNS: Drowsiness, sedation, ataxia, insomnia, aphonia, choreiform movements, coma, dysarthria, "glassy-eyed" appearance, headache, hemiparesis, hypotonia, slurred speech, tremor, vertigo, confusion, depression, hallucinations, aggressive behavior problems, hysteria, suicide attempt. Respiratory: Chest congestion, respiratory depression, rhinorrhea, dyspnea, hypersecretion in upper respiratory passages. Skin: Hirsutism, hair loss, skin rash, ankle and facial edema. Special Senses: Diplopia, nystagmus, abnormal eye movements. Urogenital: Increased libido, dysuria, enuresis, nocturia, urinary retention.

Diagnostic Test Interference

Clonazepam causes transient elevations of serum transaminase and alkaline phosphatase.

Interactions

Drug: Alcohol and other cns depressants increase sedation and CNS depression; may increase phenytoin levels. Herbal: Kava, valerian may potentiate sedation.

Pharmacokinetics

Absorption: Readily absorbed from GI tract. Onset: 60 min. Peak: 1–2 h. Duration: Up to 12 h in adults; 6–8 h in children. Distribution: Crosses placenta; distributed into breast milk. Metabolism: In liver. Elimination: In urine primarily as metabolites. Half-Life: 18–40 h.

Nursing Implications

Assessment & Drug Effects

• Monitor for signs of suicidal ideation in depressive individuals.
• Monitor I&O ratio and patterns: Excess accumulation of metabolites due to impaired excretion leads to toxicity.
• Assess carefully for signs of overdosage or drug interaction (i.e., increased depressant adverse effects) if multiple anticonvulsants are being given.
• Lab tests: Periodic liver function tests, platelet counts, blood counts, and renal function tests.
• Watch patient to see that he or she does not cheek the tablet. Both psychological and physical dependence may occur in the patient on long-term, high-dose therapy. Limit availability of large amounts of drug in the addiction-prone individual.
• Monitor for S&S of overdose, including somnolence, confusion, irritability, sweating, muscle and abdominal cramps, diminished reflexes, coma.

Patient & Family Education

• Report loss of seizure control promptly. Anticonvulsant activity is often lost after 3 mo of therapy; dosage adjustment may reestablish efficacy.
• Do not abruptly discontinue this drug. Abrupt withdrawal can precipitate seizures. Other withdrawal symptoms include convulsion, tremor, abdominal and muscle cramps, vomiting, sweating.
• Take drug as prescribed and do not alter dosing regimen without consulting physician.
• Do not self-medicate with OTC drugs before consulting the physician.
• Do not drive a car or engage in other activities requiring mental alertness and physical coordination until reaction to the drug is known. Drowsiness occurs in approximately 50% of patients.
• Carry identification (e.g., Medic Alert) bearing information about medication in use and the diagnosis.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug