Oxazepam

BRAND NAMES

• Serax (commonly used in the United States) 

• Seresta (widely used in Europe) 

• Sobril (commonly used in Scandinavian countries) 

• Murelax (in some countries) 

• Oxazepam (sold as a generic medicine in many regions)

MECHANISM OF ACTION
Oxazepam enhances the effect of GABA (gamma-aminobutyric acid) in the brain by binding to the GABA-A receptor. This increases chloride ion entry into nerve cells, making them less excitable. As a result, it produces sedative, anxiolytic, muscle-relaxant, and anticonvulsant effects by slowing down overactive brain activity.

PHARMACOKINETICS

Absorption 

Oxazepam is well absorbed orally, with peak levels in about 2–4 hours. Food may slow absorption slightly but does not reduce overall effect.

Distribution 

Oxazepam has a low to moderate volume of distribution (~0.5–1.5 L/kg), indicating it is mainly distributed in body water with limited extensive tissue accumulation.

Metabolism 

Oxazepam is metabolized in the liver by conjugation (glucuronidation) to inactive metabolites. It does not undergo significant oxidation via cytochrome P450 enzymes, making it safer in patients with liver impairment or in the elderly compared to many other benzodiazepines.

Elimination 

Oxazepam is eliminated mainly through the kidneys as inactive glucuronide metabolites in urine. It has an elimination half-life of about 5–15 hours, depending on age and liver function. There is minimal accumulation with repeated dosing due to its short to intermediate half-life.

PHARMACODYNAMICS

Oxazepam acts by enhancing the effect of GABA at the GABA-A receptor in the central nervous system. This increases inhibitory neurotransmission, leading to sedation, anxiolysis, muscle relaxation, and anticonvulsant effects. It reduces neuronal excitability without directly activating the receptor, requiring GABA to be present for its action.

ADMINISTRATION

Oxazepam is administered orally (by mouth) in tablet or capsule form. It is usually taken 2–4 times daily depending on the condition being treated, such as anxiety, insomnia, or alcohol withdrawal. It can be taken with or without food, but should be used exactly as prescribed by a doctor.

DOSAGE AND STRENGTH

• Strengths available: 10 mg, 15 mg, 30 mg tablets 

• Anxiety: usually 10–30 mg, 3–4 times daily 

• Insomnia: 15–30 mg at bedtime 

• Alcohol withdrawal: 15–30 mg, 3–4 times daily (adjusted as needed) 

• Dose is individualized based on age, severity, and response 

• Lower doses are used in elderly or liver-impaired patients

DRUG INTERACTIONS

Oxazepam, a benzodiazepine used for anxiety and alcohol withdrawal, has several important drug interactions mainly related to its central nervous system (CNS) depressant effects.

FOOD INTERACTIONS

Oxazepam can be taken with or without food, as food does not significantly affect its absorption. However, it has a significant interaction with Alcohol, which can greatly enhance its sedative effects, leading to excessive drowsiness, dizziness, respiratory depression, and impaired coordination. Patients are strongly advised to avoid alcohol while taking oxazepam.

CONTRAINDICATIONS

Oxazepam is contraindicated in individuals with known hypersensitivity to benzodiazepines. It should not be used in patients with severe respiratory depression, acute narrow-angle glaucoma, or severe liver impairment. Caution is also required in patients with a history of substance abuse or dependence.

SIDE EFFECTS

Common side effects include:

• Drowsiness or sedation 

• Dizziness  

• Fatigue  

• Weakness  

• Confusion (especially in elderly patients) 

• Impaired coordination or memory

OVER DOSAGE

Overdose of oxazepam primarily results in excessive central nervous system (CNS) depression. Symptoms may include marked drowsiness, confusion, dizziness, slurred speech, impaired coordination, and in severe cases, respiratory depression, hypotension, coma, or even death—especially when combined with other CNS depressants such as Alcohol or opioids.

TOXICITY

The primary toxicity of oxazepam is central nervous system depression, which can range from mild sedation to severe respiratory depression and coma, especially in overdose or when combined with other CNS depressants like alcohol or opioids. Although benzodiazepine overdose alone is rarely fatal, the risk increases significantly with combined drug use.