Action

Unknown. May enhance activity of gamma-aminobutyric acid, an inhibitory neurotransmitter in CNS.

Availability

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.

Off-label uses

• Acute manic episodes of bipolar disorder

• Multifocal tic disorders

• Neuralgias

• Parkinsonian dysarthria

• Periodic leg movements occurring during sleep

• Adjunctive treatment of schizophrenia

Contraindications

• Hypersensitivity to drug or other benzodiazepines

• Severe hepatic disease

• Acute angle-closure glaucoma

Precautions

Use cautiously in:

• renal impairment, chronic respiratory disease, open-angle glaucoma

• history of porphyria

• pregnant or breastfeeding patients

• children.

Administration

See Be aware that overdose may cause fatal respiratory depression or cardiovascular collapse.

• Give tablets with water, and make sure patient swallows them whole.

Adverse reactions

CNS: ataxia, fatigue, drowsiness, behavioral changes, depression, dizziness, nervousness, reduced intellectual ability

CV: palpitations

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,

leukopenia, thrombocytopenia

Hepatic: hepatitis

Musculoskeletal: myalgia

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

Interactions

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

Patient monitoring

• 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.

Patient teaching

See 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.

See 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.