Oxazepam

BRAND NAMES

Oxapam: It contains the active ingredient of oxazepam. It is available in the form of capsules used to treat the management of anxiety disorders.

MECHANISM OF ACTION

Oxazepam binds to receptors throughout the CNS, including the limbic system and the reticular formation. The effect may be mediated via the GABA receptor system. Increased neuronal membrane permeability to chloride ions promotes GABA's inhibitory actions, while a shift in chloride ions produces hyperpolarization and membrane stability.

PHARMACOKINETICS

Absorption

Peak plasma levels following oral treatment averaged 450 mg/mL and peaked around 3 hours after dosage. 

Distribution

Oxazepam's volume of distribution ranges from 0.6 to 2.0 L/kg. 

Metabolism

Oxazepam has one significant inactive metabolite, a glucuronide conjugate. UGT2B15 catalyzes the glucuronidation of the S-isomer. UGT1A9 and UGT2B7 catalyze the glucuronidation of the R-isomer.

Excretion

Oxazepam is largely excreted in urine as its glucuronide metabolite, with feces containing around 21% of the unaltered medication. The bulk of an orally consumed oxazepam dosage is eliminated within 48 hours.

PHARMACODYNAMICS

Oxazepam has sedative and anxiolytic effects by increasing the effects of endogenous GABA, the principal inhibitory neurotransmitter in the CNS. Compared to other benzodiazepines, it has a modest potency and a moderate duration of effect. Oxazepam should be provided with caution to patients whose blood pressure drops might lead to cardiac problems, as it can cause hypotension in rare situations.

DOSAGE AND ADMINISTRATION

Oxazepam is available as a capsule to be taken orally. It is typically taken three to four times a day and can be taken with or without food. 

The pills' strengths are 10mg, 15mg, and 30mg.

DRUG INTERACTIONS

Drug interactions with oxazepam may include

Gout medicine—probenecid

Muscle relaxants: tizanidine, baclofen

Anti-convulsants: phenytoin

Antibiotics: rifampicin

Anti-virals: ritonavir and zidovudine

Anti-Parkinsons: levodopa

Anti-psychotics: aripiprazole and quetiapine

Drugs to treat nausea and vomiting: nabilone

Anti-depressants: duloxetine, venlafaxine, escitalopram, pregabalin, and sertraline

Pain relievers and fever reducers—acetaminophen

Opioid pain killers—codeine

CONTRAINDICATIONS

Patients who have shown allergy to prior oxazepam or other benzodiazepines should avoid using oxazepam. Oxazepam is not suggested for older people since it increases the risk of dependency, cognitive impairment, and falls. Oxazepam may pass the placenta and be excreted in breast milk; hence, it is not suggested as a pharmacological treatment in pregnant or breastfeeding women. Patients receiving oxazepam for insomnia should avoid caffeine-containing items, which may reduce the drug's effectiveness. Coadministering oxazepam with other CNS depressants, such as diphenhydramine or hydrocodone, may intensify the CNS impact.

SIDE EFFECTS

Oxazepam may cause side effects that may include

• Drowsiness
• Dizziness
• Tiredness
• Weakness
• Diarrhea
• Upset stomach
• Changes in appetite
• Restlessness or excitement
• Constipation
• Difficulty urination
• Frequent urination
• Blurred vision

Some side effects can be serious.

• Shuffling walk
• Fever
• Difficulty breathing
• Severe skin rash
• Yellowing of the skin or eye
• Irregular heartbeat

 OVERDOSE

Symptoms of overdose may include

• Severe drowsiness
• Reduced reflexes
• Slowed breathing
• Fainting
• Loss of consciousness

TOXICITY

A patient with an oxazepam overdose often has normal vital signs but profound CNS depression. Comatose individuals are frequently found with severe poisoning. Respiratory compromise most usually happens when patients voluntarily combine benzodiazepine with another sedative medication, such as an opioid. Oxazepam is the least sedative of all benzodiazepines due to its delayed absorption. If poisoning is suspected, airway, breathing, and circulation must be maintained immediately. Intubation may be required if there is a serious compromise.