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Back to Benzodiazipines

Name: Clonazepam

C-IV controlled substance
Pregnancy Category D

Drug classes

  • Benzodiazepine
  • Antiepileptic drug

Therapeutic actions

Exact mechanisms of action not understood; benzodiazepines potentiate the effects of GABA, an inhibitory neurotransmitter.

Indications

Used alone or as adjunct in treatment of Lennox-Gastaut syndrome (petit mal variant), akinetic and myoclonic seizures; may be useful in patients with absence (petit mal) seizures who have not responded to succinimides; up to 30% of patients show loss of effectiveness of drug, often within 3 mo of therapy (may respond to dosage adjustment).

Unlabeled uses: treatment of panic attacks, periodic leg movements during sleep, hypokinetic dysarthria, acute manic episodes, multifocal tic disorders, adjunct treatment of schizophrenia, neuralgias

Contraindications/cautions

Contraindicated in the presence of hypersensitivity to benzodiazepines, psychoses, acute narrow-angle glaucoma, shock, coma, acute alcoholic intoxication with depression of vital signs; pregnancy (increased risk of congenital malformations, neonatal withdrawal syndrome), labor and delivery ("floppy infant" syndrome reported), lactation (infants become lethargic and lose weight).

Use caution in the presence of impaired liver or kidney function, debilitation.

Adverse effects

  • CNS: Transient, mild drowsiness initially; sedation, depression, lethargy, apathy, fatigue, lightheadedness, disorientation, anger, hostility, episodes of mania and hypomania, restlessness, confusion, crying, delirium, headache, slurred speech, dysarthria, stupor, rigidity, tremor, dystonia, vertigo, euphoria, nervousness, difficulty in concentration, vivid dreams, psychomotor retardation, extrapyramidal symptoms; mild paradoxical excitatory reactions, during first two weeks of treatment
  • GI: Constipation, diarrhea, dry mouth, salivation, nausea, anorexia, vomiting, difficulty in swallowing, gastric disorders, hepatic dysfunction, encoporesis
  • CV: Bradycardia, tachycardia, cardiovascular collapse, hypertension and hypotension, palpitations, edema
  • Hematologic: Elevations of blood enzymes: LDH, alkaline phosphatase, SGOT, SGPT; blood dyscrasias: agranulocytosis, leukopenia
  • GU: Incontinence, urinary retention, changes in libido, menstrual irregularities
  • EENT: Visual and auditory disturbances, diplopia, nystagmus, depressed hearing, nasal congestion
  • Dermatologic: Urticaria, pruritus, skin rash, dermatitis
  • Other: Hiccups, fever, diaphoresis, paresthesias, muscular disturbances, gynecomastia. Drug dependence with withdrawal syndrome when drug is discontinued more common with abrupt discontinuation of higher dosage used for longer than 4 mo.

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