Oxazepam

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Capsule, Oral:

Generic: 10 mg, 15 mg, 30 mg

Pharmacology

Mechanism of Action

Binds to stereospecific benzodiazepine receptors on the postsynaptic GABA neuron at several sites within the central nervous system, including the limbic system, reticular formation. Enhancement of the inhibitory effect of GABA on neuronal excitability results by increased neuronal membrane permeability to chloride ions. This shift in chloride ions results in hyperpolarization (a less excitable state) and stabilization. Benzodiazepine receptors and effects appear to be linked to the GABA-A receptors. Benzodiazepines do not bind to GABA-B receptors (Vinkers 2012).

Pharmacokinetics/Pharmacodynamics

Absorption

Slowly absorbed from the GI tract (Greenblatt 1981)

Distribution

V_d: 0.6 to 2 L/kg (Greenblatt 1981)

Metabolism

Hepatic glucuronide conjugation to produce a single, major inactive metabolite (benzophenone) (Greenblatt 1981)

Excretion

Urine (as inactive glucuronide conjugate)

Time to Peak

Serum: ~3 hours

Half-Life Elimination

~8 hours (range: 6 to 11 hours)

Protein Binding

96% to 98% (Greenblatt 1981)

Use in Specific Populations

Special Populations: Renal Function Impairment

In patients with severe renal insufficiency, the elimination half-life of oxazepam was prolonged to a mean of 48 hours (range: 24 to 91); however, clearance of total drug was relatively normal suggesting that a large increase in volume of distribution accounts for the prolongation in half-life (Greenblatt 1981).

Special Populations: Elderly

A statistically significant increase in elimination half-life in patients >80 years of age has been reported, due to a 30% increase in volume of distribution and a 50% reduction in unbound clearance of oxazepam.

Special Populations: Gender

A small but statistically significant prolongation of half-life elimination (9.7 hours versus 7.8 hours) and reduction of total clearance (0.82 mL/minute/kg versus 1.15 mL/minute/kg) has been reported in females in comparison to males, respectively (Greenblatt 1981).

Use: Labeled Indications

Alcohol withdrawal: Treatment of acute tremulousness, inebriation, or anxiety associated with alcohol withdrawal

Anxiety disorders: Treatment of anxiety disorders or short-term relief of the symptoms of anxiety, including anxiety associated with depression and anxiety, tension, agitation, and irritability in older patients.

Contraindications

Hypersensitivity to oxazepam or any component of the formulation.

Documentation of allergenic cross-reactivity for drugs in this class is limited. However, because of similarities in chemical structure and/or pharmacologic actions, the possibility of cross-sensitivity can not be ruled out with certainty.

Dosage and Administration

Dosing: Adult

Alcohol withdrawal: Oral: 15 to 30 mg 3 to 4 times daily

Anxiety, mild to moderate: Oral: 10 to 15 mg 3 to 4 times daily

Anxiety (severe), agitation, or anxiety associated with depression: Oral: 15 to 30 mg 3 to 4 times daily

Dosing: Geriatric

Anxiety: Oral: Initial: 10 mg 3 times daily. If necessary, increase cautiously to 15 mg 3 to 4 times daily.

Dosing: Pediatric

Children >12 years and Adolescents: Refer to adult dosing.

Storage

Store at 20°C to 25°C (68°F to 77°F). Protect from moisture.

Drug Interactions

Alcohol (Ethyl): CNS Depressants may enhance the CNS depressant effect of Alcohol (Ethyl). Monitor therapy

Alizapride: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Azelastine (Nasal): CNS Depressants may enhance the CNS depressant effect of Azelastine (Nasal). Avoid combination

Blonanserin: CNS Depressants may enhance the CNS depressant effect of Blonanserin. Consider therapy modification

Brexanolone: CNS Depressants may enhance the CNS depressant effect of Brexanolone. Monitor therapy

Brimonidine (Topical): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Bromopride: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Bromperidol: May enhance the CNS depressant effect of CNS Depressants. Avoid combination

Buprenorphine: CNS Depressants may enhance the CNS depressant effect of Buprenorphine. Management: Consider reduced doses of other CNS depressants, and avoiding such drugs in patients at high risk of buprenorphine overuse/self-injection. Initiate buprenorphine at lower doses in patients already receiving CNS depressants. Consider therapy modification

Cannabidiol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Cannabis: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Chlormethiazole: May enhance the CNS depressant effect of CNS Depressants. Management: Monitor closely for evidence of excessive CNS depression. The chlormethiazole labeling states that an appropriately reduced dose should be used if such a combination must be used. Consider therapy modification

Chlorphenesin Carbamate: May enhance the adverse/toxic effect of CNS Depressants. Monitor therapy

CloZAPine: Benzodiazepines may enhance the adverse/toxic effect of CloZAPine. Management: Consider decreasing the dose of (or possibly discontinuing) benzodiazepines prior to initiating clozapine. Consider therapy modification

CNS Depressants: May enhance the adverse/toxic effect of other CNS Depressants. Monitor therapy

Dimethindene (Topical): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Doxylamine: May enhance the CNS depressant effect of CNS Depressants. Management: The manufacturer of Diclegis (doxylamine/pyridoxine), intended for use in pregnancy, specifically states that use with other CNS depressants is not recommended. Monitor therapy

Dronabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Droperidol: May enhance the CNS depressant effect of CNS Depressants. Management: Consider dose reductions of droperidol or of other CNS agents (eg, opioids, barbiturates) with concomitant use. Exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Consider therapy modification

Esketamine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Flunitrazepam: CNS Depressants may enhance the CNS depressant effect of Flunitrazepam. Consider therapy modification

Fosphenytoin: Benzodiazepines may increase the serum concentration of Fosphenytoin. Short-term exposure to benzodiazepines may not present as much risk as chronic therapy. Monitor therapy

HYDROcodone: CNS Depressants may enhance the CNS depressant effect of HYDROcodone. Management: Avoid concomitant use of hydrocodone and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Consider therapy modification

HydrOXYzine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Kava Kava: May enhance the adverse/toxic effect of CNS Depressants. Monitor therapy

Lemborexant: May enhance the CNS depressant effect of CNS Depressants. Management: Dosage adjustments of lemborexant and of concomitant CNS depressants may be necessary when administered together because of potentially additive CNS depressant effects. Close monitoring for CNS depressant effects is necessary. Consider therapy modification

Lofexidine: May enhance the CNS depressant effect of CNS Depressants. Management: Drugs listed as exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Monitor therapy

Magnesium Sulfate: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Melatonin: May enhance the sedative effect of Benzodiazepines. Monitor therapy

Methadone: Benzodiazepines may enhance the CNS depressant effect of Methadone. Management: Clinicians should generally avoid concurrent use of methadone and benzodiazepines when possible; any combined use should be undertaken with extra caution. Consider therapy modification

Methotrimeprazine: CNS Depressants may enhance the CNS depressant effect of Methotrimeprazine. Methotrimeprazine may enhance the CNS depressant effect of CNS Depressants. Management: Reduce adult dose of CNS depressant agents by 50% with initiation of concomitant methotrimeprazine therapy. Further CNS depressant dosage adjustments should be initiated only after clinically effective methotrimeprazine dose is established. Consider therapy modification

MetyroSINE: CNS Depressants may enhance the sedative effect of MetyroSINE. Monitor therapy

Minocycline (Systemic): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Nabilone: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

OLANZapine: May enhance the adverse/toxic effect of Benzodiazepines. Management: Avoid concomitant use of parenteral benzodiazepines and IM olanzapine due to risks of additive adverse events (e.g., cardiorespiratory depression). Olanzapine prescribing information provides no specific recommendations regarding oral administration. Avoid combination

Opioid Agonists: CNS Depressants may enhance the CNS depressant effect of Opioid Agonists. Management: Avoid concomitant use of opioid agonists and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Consider therapy modification

Orphenadrine: CNS Depressants may enhance the CNS depressant effect of Orphenadrine. Avoid combination

Oxomemazine: May enhance the CNS depressant effect of CNS Depressants. Avoid combination

OxyCODONE: CNS Depressants may enhance the CNS depressant effect of OxyCODONE. Management: Avoid concomitant use of oxycodone and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Consider therapy modification

Paraldehyde: CNS Depressants may enhance the CNS depressant effect of Paraldehyde. Avoid combination

Perampanel: May enhance the CNS depressant effect of CNS Depressants. Management: Patients taking perampanel with any other drug that has CNS depressant activities should avoid complex and high-risk activities, particularly those such as driving that require alertness and coordination, until they have experience using the combination. Consider therapy modification

Phenytoin: Benzodiazepines may increase the serum concentration of Phenytoin. Short-term exposure to benzodiazepines may not present as much risk as chronic therapy. Monitor therapy

Piribedil: CNS Depressants may enhance the CNS depressant effect of Piribedil. Monitor therapy

Pramipexole: CNS Depressants may enhance the sedative effect of Pramipexole. Monitor therapy

ROPINIRole: CNS Depressants may enhance the sedative effect of ROPINIRole. Monitor therapy

Rotigotine: CNS Depressants may enhance the sedative effect of Rotigotine. Monitor therapy

Rufinamide: May enhance the adverse/toxic effect of CNS Depressants. Specifically, sleepiness and dizziness may be enhanced. Monitor therapy

Selective Serotonin Reuptake Inhibitors: CNS Depressants may enhance the adverse/toxic effect of Selective Serotonin Reuptake Inhibitors. Specifically, the risk of psychomotor impairment may be enhanced. Monitor therapy

Sodium Oxybate: Benzodiazepines may enhance the CNS depressant effect of Sodium Oxybate. Avoid combination

Suvorexant: CNS Depressants may enhance the CNS depressant effect of Suvorexant. Management: Dose reduction of suvorexant and/or any other CNS depressant may be necessary. Use of suvorexant with alcohol is not recommended, and the use of suvorexant with any other drug to treat insomnia is not recommended. Consider therapy modification

Tapentadol: May enhance the CNS depressant effect of CNS Depressants. Management: Avoid concomitant use of tapentadol and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Consider therapy modification

Teduglutide: May increase the serum concentration of Benzodiazepines. Monitor therapy

Tetrahydrocannabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Tetrahydrocannabinol and Cannabidiol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Thalidomide: CNS Depressants may enhance the CNS depressant effect of Thalidomide. Avoid combination

Theophylline Derivatives: May diminish the therapeutic effect of Benzodiazepines. Consider therapy modification

Trimeprazine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Yohimbine: May diminish the therapeutic effect of Antianxiety Agents. Monitor therapy

Zolpidem: CNS Depressants may enhance the CNS depressant effect of Zolpidem. Management: Reduce the Intermezzo brand sublingual zolpidem adult dose to 1.75 mg for men who are also receiving other CNS depressants. No such dose change is recommended for women. Avoid use with other CNS depressants at bedtime; avoid use with alcohol. Consider therapy modification

Adverse Reactions

Frequency not defined.

Cardiovascular: Edema, hypotension, syncope

Central nervous system: Amnesia, ataxia, dizziness, drowsiness, drug dependence, dysarthria, euphoria, headache, lethargy, memory impairment, slurred speech, vertigo

Dermatologic: Maculopapular rash, morbilliform rash, urticaria

Endocrine & metabolic: Decreased libido, menstrual disease

Gastrointestinal: Nausea

Genitourinary: Urinary incontinence

Hematologic & oncologic: Hematologic disease, leukopenia

Hepatic: Jaundice

Hypersensitivity: Fixed drug eruption

Neuromuscular & skeletal: Hyporeflexia, tremor

Ophthalmic: Blurred vision, diplopia

Miscellaneous: Paradoxical central nervous system stimulation, paradoxical excitation

Warnings/Precautions

Concerns related to adverse effects:

• Anterograde amnesia: Benzodiazepines have been associated with anterograde amnesia (Nelson 1999).
• CNS depression: May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).
• Hypotension: May cause hypotension (rare); use with caution in patients with cardiovascular or cerebrovascular disease, or in patients who would not tolerate transient decreases in blood pressure.
• Paradoxical reactions: Paradoxical reactions, including hyperactive or aggressive behavior, have been reported with benzodiazepines, particularly in adolescent/pediatric or psychiatric patients (Mancuso 2004).
• Sleep-related activities: Hazardous sleep-related activities such as sleep-driving, cooking and eating food, and making phone calls while asleep have been noted with benzodiazepines (Dolder 2008).

Disease-related concerns:

• Depression: Use benzodiazepines with caution in patients with depression, particularly if suicidal risk may be present.
• Drug abuse: Use with caution in patients with a history of drug abuse or acute alcoholism; potential for drug dependency exists. Psychological and physical dependence may occur with prolonged use.
• Hepatic impairment: Use with caution in patients with hepatic impairment; however, oxazepam has been shown to be less affected by hepatic dysfunction due to its relative slow extraction by the liver and phase II metabolic pathway (glucuronidation) (Furlan 1999; Greenblatt 1981).
• Respiratory disease: Use with caution in patients with respiratory disease.

Concurrent drug therapy issues:

• Concomitant use with opioids: [US Boxed warning]: Concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate. Limit dosages and durations to the minimum required. Follow patients for signs and symptoms of respiratory depression and sedation.
• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

• Elderly: Relative to other benzodiazepines, oxazepam possesses a short half-life and lacks an active metabolite which may be preferable in the elderly if benzodiazepine use is required for anxiety (Flint 2005). Kinetics were not altered in patients of advanced age compared to younger patients, except in patients >80 years of age where an increased half-life was observed due to an increased volume of distribution and a decrease in unbound clearance. Elderly patients may be at an increased risk of death with use; risk has been found highest within the first 4 months of use in elderly dementia patients (Jennum 2015; Saarelainen 2018).
• Fall risk: Use with extreme caution in patients who are at risk of falls; benzodiazepines have been associated with falls and traumatic injury (Nelson 1999).

Other warnings/precautions:

• Appropriate use: Does not have analgesic, antidepressant, or antipsychotic properties; not indicated for use in the treatment of psychosis.
• Tolerance: Oxazepam is a short half-life benzodiazepine. Duration of action after a single dose is determined by redistribution rather than metabolism. Tolerance does not develop to the anxiolytic effects (Vinkers 2012). Chronic use of this agent may increase the perioperative benzodiazepine dose needed to achieve desired effect.
• Withdrawal: Rebound or withdrawal symptoms may occur following abrupt discontinuation or large decreases in dose. Use caution when reducing dose or withdrawing therapy; decrease slowly and monitor for withdrawal symptoms. Flumazenil may cause withdrawal in patients receiving long-term benzodiazepine therapy.

Monitoring Parameters

Respiratory and cardiovascular status (as clinically indicated); CBC (periodic); liver function tests (periodic)

Pregnancy

Pregnancy Considerations

Oxazepam crosses the placenta. Teratogenic effects have been observed with some benzodiazepines; however, additional studies are needed. The incidence of premature birth and low birth weights may be increased following maternal use of benzodiazepines; hypoglycemia and respiratory problems in the neonate may occur following exposure late in pregnancy. Neonatal withdrawal symptoms may occur within days to weeks after birth and “floppy infant syndrome” (which also includes withdrawal symptoms) have been reported with some benzodiazepines (Bergman 1992; Iqbal 2002; Kangas 1980; Wikner 2007).

Patient Education

What is this drug used for?

• It is used to treat alcohol withdrawal.
• It is used to treat anxiety.

Frequently reported side effects of this drug

• Fatigue
• Headache

Other side effects of this drug: Talk with your doctor right away if you have any of these signs of:

• Severe dizziness
• Passing out
• Change in balance
• Trouble with memory
• Signs of a significant reaction like wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.