Oxazepam (Serax®)

Controlled Substances

Only midwives who have completed the “Opioids and Benzodiazepines: Safe Prescribing for Midwives” course may independently prescribe controlled substances.

Oxazepam is a benzodiazepine, anti-anxiety agent and sedative which binds to benzodiazepine receptors on the postsynaptic neuron at several sites within the central nervous system.

Indications and Clinical Use:

Midwives may only prescribe, order or administer oxazepam on their own authority for 1) therapeutic rest in prodromal labour, 2) short-term management of excessive postpartum anxiety while the midwife is arranging for consultation with a physician for further diagnosis and ongoing treatment or 3) upon diagnosis of intrauterine fetal demise. Oxazepam may be used for therapeutic rest during prodromal labour; it has a half-life of up to 8 hours, however use of analgesia may be more appropriate over oxazepam as a first choice. Oxazepam may be used during the early postpartum period, particularly where anxiety or insomnia due to anxiety or transient stress are factors and non-pharmacologic measures have been ineffective. Administration under any other circumstance must be on the order of a physician.

Contraindications:

Hypersensitivity to benzodiazepines or to any component of the formulation. Oxazepam should not be taken in conjunction with alcohol or other sedating medications.

Benzodiazepines should not be used in the presence of the following medical conditions: glaucoma, liver or kidney impairment, hyperkinesias, hypoalbuminaemia, myasthenia gravis, or any type of organic brain disorder. Benzodiazepines should not be given where there is a history of substance use or dependency.

Benzodiazepines are not recommended in the first trimester of pregnancy because of the potential for congenital malformations. When these drugs are taken to treat anxiety disorders, information on the risks and alternate approaches to therapy should be offered.

Warnings and Precautions:

All practitioners caring for an individual taking a benzodiazepine should be aware that long-term use can result in dependency and withdrawal symptoms when the medication is discontinued. Prolonged doses of benzodiazepines during pregnancy and/or the postpartum period may cause physical dependence with resulting withdrawal symptoms in the neonate. Before prescribing, ordering or administering a benzodiazepine to a client with a depressive, chronic psychotic, phobic or obsessive behavioral disorder or potential suicidal tendencies, consultation with a physician is required.

While a benzodiazepine may be prescribed for postpartum psychosis, these medications enter breast milk and, if used during breastfeeding, midwives should watch for possible sedation, feeding difficulties and weight loss in the neonate. Hypoglycemia and respiratory problems in the neonate may occur following exposure late in pregnancy. While elimination of benzodiazepines in the neonate following in utero exposure can be slow, oxazepam is considered a short-acting benzodiazepine (less than or equal to 12 hours) and the least lipid-soluble, so levels in breast milk tend to be low. Thus, oxazepam is considered safer during lactation than other benzodiazepines, especially if its use is short-term or intermittent.

Benzodiazepines given near delivery could cause respiratory depression and hypoglycemia in neonates. Prolonged use in gestation may cause neonatal withdrawal.

Benzodiazepines have been associated with anterograde amnesia; may impair physical or mental abilities; may cause hypotension; may cause hyperactive or aggressive behavior.

Use with caution in the presence of hepatic impairment, renal impairment, respiratory disease, substance use, alcohol use, personality disorders or depression.

When taking this medication one should not operate machinery or drive a vehicle.

Pregnancy:

Human Data Suggest Risk in 1st and 3rd Trimesters

Although a number of studies have reported an association with various types of congenital defects, other studies with this class of drugs have not found such associations. Denial of exposure and the concurrent exposure to other toxic drugs and substances (e.g., alcohol and smoking) may be confounding factors. Continuous use during gestation or close to delivery might result in neonatal withdrawal or a dose-related syndrome similar to that observed with diazepam.

Lactation:

Category L 2 – Limited Data- Probably Compatible

Oxazepam is one of the preferred benzodiazepines in lactation due to its shorter half-life and lack of an active metabolite. About 1% of the dose is known to enter breastmilk. If this medication is used in lactation the lowest effective dose should be given for the shortest possible period of time. The neonate should also be monitored for signs of sedation such as not waking up to feed at regular intervals.

Adverse Reactions:

Benzodiazepines may cause drowsiness, blurred vision, dizziness and impaired concentration. Other potential side effects include lack of muscle coordination, nausea, constipation, visual disturbances, skin rash, and loss of bladder control. If breathing difficulties, fainting, rash or hypotension are experienced a physician should be contacted immediately.

Clinical judgement should be exercised as benzodiazepines cross the placental barrier. Should labour progress more rapidly than anticipated, Flumazenil, a benzodiazepine receptor antagonist, may be required and should be readily available for administration. Immediately after administration physician consultation is required. (Please refer to the section on Flumazenil at the end of the benzodiazepine section).

Dosage and Administration:

Usual dose

Insomnia – 10-30 mg PO at bedtime

Anxiety – 10-30 mg PO TID-QID

In prodromal labour the dose may be repeated 8 or 12 hours following first dose if active labour is not yet established. No more than two consecutive doses should be given. In treating postpartum anxiety, the dose may be repeated every 8 to 12 hours in the postpartum period for no more than 3 days or a maximum of six doses. Once postpartum treatment is initiated physician consultation must be arranged.

Onset of Action:

Peak of action is 2-4 hours

Half-Life:

Adult – 8 hours

Neonate – unknown

Excretion:

Urine as metabolites

Prescription:

Oxazepam may be prescribed in hospital or in the community. It does not require a duplicate prescription pad. A prescription cannot exceed three days. No refills. Please be sure to follow the guidelines on page 2 of this document.