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Oxazepam

Pronunciation

Pronunciation

(oks A ze pam)

Index Terms

  • Serax

Dosage Forms

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

Capsule, Oral:

Generic: 10 mg, 15 mg, 30 mg

Pharmacologic Category

  • Benzodiazepine

Pharmacology

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.

Absorption

Slowly absorbed from the GI tract (Greenblatt, 1981)

Distribution

Vd: 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%

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

Management of anxiety disorders, including anxiety associated with depression; management of ethanol withdrawal

Contraindications

Hypersensitivity to oxazepam or any component of the formulation (cross-sensitivity with other benzodiazepines may exist)

Dosing: Adult

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

Anxiety, severe or associated with depression: Oral: 15-30 mg 3-4 times daily

Ethanol withdrawal: Oral: 15-30 mg 3-4 times daily

Dosing: Geriatric

Anxiety: Oral: Initial: 10 mg 3 times daily. If necessary, increase cautiously to 15 mg 3-4 times daily. Dose titration should be slow to evaluate sensitivity.

Dosing: Pediatric

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

Dosing: Renal Impairment

No dosage adjustment provided in manufacturer's labeling

Hemodialysis: Not dialyzable (0% to 5%) (Greenblatt, 1981; Mokhlesi, 2003)

Dosing: Hepatic Impairment

No dosage adjustment provided in manufacturer's labeling; however, pharmacokinetic studies have shown that hepatic dysfunction is not expected to significantly decrease clearance (Furlan, 1999; Greenblatt, 1981).

Administration

Administer orally in divided doses.

Drug Interactions

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

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

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 patches (Butrans brand) at 5 mcg/hr in adults when used with other CNS depressants. Consider therapy modification

Cannabis: May enhance the CNS depressant 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. Exceptions: Levocabastine (Nasal). 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 (e.g., opioids, barbiturates) with concomitant use. 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: Consider starting with a 20% to 30% lower hydrocodone dose when using together with any other CNS depressant. Dose reductions in the other CNS depressant may also be warranted. 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

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

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

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

Mirtazapine: CNS Depressants may enhance the CNS depressant effect of Mirtazapine. 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

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

OxyCODONE: CNS Depressants may enhance the CNS depressant effect of OxyCODONE. Management: When oxycodone is combined with another CNS depressant, a dose reduction of one or both agents should be considered. The extended release oxycodone starting dose should be reduced 50% to 67% when initiated in patients already receiving CNS depressants. 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

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: Start tapentadol at a dose of one-third to one-half of the normal dose if being initiated in a patient who is taking another drug with CNS depressant effects. Monitor closely for evidence of excessive CNS depression. 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

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:

• 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.

• Transient amnesia: Benzodiazepines have been associated with transient amnesia.

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. Tolerance, 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).

• Impaired gag reflex: Use with caution in patients with an impaired gag reflex.

• Respiratory disease: Use with caution in patients with respiratory disease.

Concurrent drug therapy issues:

• CNS depressants/psychoactive medications: Use with caution in patients receiving other CNS depressants or psychoactive medication; effects with other sedative drugs or ethanol may be potentiated.

Special populations:

• Debilitated patients: Use with caution in debilitated patients.

• 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.

• Fall risk: Use with extreme caution in patients who are at risk of falls; benzodiazepines have been associated with falls and traumatic injury.

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; periodic CBC and liver function tests

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

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience fatigue or headache. Have patient report immediately to prescriber signs of hepatic impairment, severe dizziness, syncope, change in balance, edema, dysarthria, tremors, decreased libido, chills, pharyngitis, or memory impairment (HCAHPS).

• Educate patient about signs of a significant reaction (eg, 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. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.

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