oxazepam
Apo-Oxazepam ◆, Novoxapam ◆, Serax

Available forms
Available by prescription only
Capsules: 10 mg, 15 mg, 30 mg
Tablets: 15 mg

Indications and dosages
 Alcohol withdrawal, severe anxiety. Adults: 15 to 30 mg P.O. t.i.d. or q.i.d.
 Tension, mild to moderate anxiety. Adults: 10 to 15 mg P.O. t.i.d. or q.i.d.
≡ Dosage adjustment. For older adults, give 10 mg P.O. t.i.d.; then increase to 15 mg t.i.d. or q.i.d., p.r.n.

Pharmacodynamics
Anxiolytic and sedative-hypnotic actions: Oxazepam depresses the CNS at the limbic and subcortical levels of the brain. It produces an antianxiety effect by enhancing the effect of the neurotransmitter gamma-aminobutyric acid on its receptor in the ascending reticular activating system, which increases inhibition and blocks both cortical and limbic arousal.

Pharmacokinetics
Absorption: Well absorbed through the GI tract.
Distribution: Distributed widely throughout the body; 85% to 95% protein-bound.
Metabolism: Metabolized in the liver to inactive metabolites.
Excretion: Metabolites are excreted in urine as glucuronide conjugates. Half-life of drug is 5 3/4 to 20 hours.

Contraindications and precautions
Contraindicated in patients hypersensitive to drug and patients with psychosis. Use cautiously in elderly or debilitated patients; in those with history of drug abuse; and in those for whom decreased blood pressure is linked to cardiac problems.

Interactions
Drug-drug. Antacids: May decrease rate but not extent of oxazepam absorption. Separate administration times of these drugs.
Antidepressants, antihistamines, barbiturates, general anesthetics, MAO inhibitors, narcotics, phenothiazines: Potentiates CNS depressant effects of these drugs. Avoid use together, if possible.
Cimetidine, disulfiram: Causes risk of decreased hepatic metabolism and increases plasma levels of oxazepam. Monitor patient carefully.
Levodopa: Inhibits therapeutic effects of levodopa. Monitor patient closely.
Theophylline: May antagonize effects of benzodiazepines. Monitor patient for effect.
Drug-herb. Catnip, kava, lady’s slipper, lemon balm, passionflower, sassafras, skullcap, valerian: May enhance sedative effects. Discourage use together.
Drug-lifestyle. Alcohol use: Potentiates CNS depressant effects. Discourage alcohol use.
Caffeine: May antagonize effects of benzodiazepines. Monitor patient for effect.
Heavy smoking: Accelerates oxazepam metabolism and reduces effectiveness. Discourage smoking.

Adverse reactions
CNS: drowsiness, lethargy, dizziness, vertigo, headache, syncope, tremor, slurred speech, changes in EEG patterns.
CV: edema.
GI: nausea.
Hepatic: hepatic dysfunction.
Skin: rash.
Other: altered libido.

Effects on lab test results
None reported.

Overdose and treatment
Signs and symptoms of overdose include somnolence, confusion, coma, hypoactive reflexes, dyspnea, labored breathing, hypotension, bradycardia, slurred speech, and unsteady gait or impaired coordination.
 Support blood pressure and respiration until drug effects have subsided; monitor vital signs. Mechanical ventilatory assistance via endotracheal tube may be needed to maintain a patent airway and support oxygenation. Flumazenil, a specific benzodiazepine antagonist, may be useful and should be kept readily available. As needed, give I.V. fluids and vasopressors, such as dopamine and phenylephrine, to treat hypotension. If the patient is conscious, induce emesis. Use gastric lavage if ingestion was recent, but only if an endotracheal tube is present to prevent aspiration. After emesis or lavage, administer activated charcoal with a cathartic as a single dose. Dialysis is of limited value.

Special considerations
• Oxazepam tablets contain tartrazine dye; check patient’s history for allergy to this substance.
• Store drug in a cool, dry place away from light.
• Use of drug for longer than 4 months hasn’t been established.
• Gradually reduce dosage (over 8 to 12 weeks) after long-term use.
• Ensure safety precautions, such as siderails in the upright position; patient should be assisted while walking to prevent falls.
• Monitor hepatic and renal function test results to ensure normal function.
Breast-feeding patients
• The breast-fed infant of a woman who uses oxazepam may become sedated, have feeding difficulties, or lose weight. Avoid use in breast-feeding women.
Pediatric patients
• Safety in children younger than age 6 hasn’t been established. Closely observe neonate for withdrawal symptoms if mother took oxazepam for a prolonged period during pregnancy.
Geriatric patients
• These patients are more susceptible to CNS depressant effects of oxazepam. Some may need assistance with walking and activities of daily living when therapy starts or dosage increases.
• Reduced dosages are usually effective in elderly patients because of their decreased elimination.

Patient education
• Advise patient not to change drug regimen without medical approval.
• Instruct patient in safety measures, such as gradual position changes and assisted ambulation, to prevent injury.
• Because sleepiness may not occur for up to 2 hours after taking oxazepam, tell patient to wait before taking an additional dose.
• Advise patient of risk for physical and psychological dependence with long-term use of oxazepam.
• Advise patient to avoid alcohol.
• Tell patient to avoid driving or other activities that require mental alertness after taking drug.
• Tell patient not to stop drug suddenly if he has been taking it for a long time.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use