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A plain-language summary of the cited sources below. Informational only — not medical advice.
Diazepam works by enhancing the effect of a natural calming chemical in the brain called GABA. When diazepam attaches to GABA receptors, it makes those receptors more responsive to GABA, which increases the flow of chloride ions into nerve cells and slows down brain activity. This produces a calming effect, reduces anxiety, and relaxes muscles.
Diazepam may be prescribed for several reasons: to manage anxiety disorders or provide short-term relief from anxiety symptoms; to help with acute alcohol withdrawal symptoms including agitation, tremor, and delirium tremens; and to relieve muscle spasm caused by local injury, inflammation, or conditions affecting movement such as cerebral palsy, paraplegia, athetosis, or stiff-man syndrome.
The medication stays in the body for quite a long time. Diazepam itself has a typical elimination half-life of 24 to 48 hours, and it breaks down into an active metabolite called desmethyldiazepam that remains active for 40 to 100 hours. This means effects can build up over time with repeated doses. The breakdown process happens in the liver through specific enzymes; desmethyldiazepam is formed mainly by CYP2C19 and CYP3A enzymes, while other breakdown products are formed by CYP3A. This matters because other medications that affect these same enzymes can change how quickly diazepam is processed in the body.
Common side effects your family member may experience include fatigue, drowsiness, muscle weakness, ataxia (loss of coordination), and dizziness. These effects reflect the medication's action on the nervous system and may affect their ability to move safely or stay alert.
There are also serious adverse effects to watch for. These include cardiac failure and cardiac arrest; respiratory depression that can progress to respiratory failure; increased risk of falls and fractures; and paradoxical reactions where the person becomes more restless, agitated, aggressive, nervous, hostile, anxious, delusional, angry, or experiences nightmares, hallucinations, or other distressing behavioural changes rather than becoming calmer. Chronic use, even at therapeutic doses, may lead to physical dependence, meaning that stopping the medication suddenly can trigger withdrawal symptoms or rebound phenomena where the original symptoms return more intensely. Diazepam should not be used in people with known hypersensitivity to benzodiazepines or diazepam; chronic obstructive pulmonary disease with incipient respiratory failure; severe respiratory insufficiency; severe liver impairment; sleep apnoea syndrome; myasthenia gravis; or dependence on CNS depressants including alcohol, except when managing acute alcohol withdrawal.
Common off-label uses observed in AU practice — none of these are TGA-approved indications for this substance. If the documented purpose is one of these, the prescription falls outside the TGA-approved set and may sit inside the chemical-restraint frame depending on jurisdiction and context.
These are practitioner observations, not TGA-approved indications. A use being off-label does not by itself imply a regulated restrictive practice; review the documented purpose against the observed function in context.
Tier 4 · ObservationChronic spasticity Clinical criteria: Population criteria: Patient must be under 18 years of age.
Anxiety Clinical criteria: Patient must be receiving palliative care.
“The central actions of benzodiazepines are mediated through enhancement of the GABAergic neurotransmission at inhibitory synapses. In the presence of benzodiazepines, the affinity of the GABA receptor for the neurotransmitter is enhanced through positive allosteric modulation resulting in an increased action of released GABA on the postsynaptic transmembrane chloride ion flux.”
“Typical elimination half-life values are in the range of 24 - 48 hours for diazepam and 40 - 100 hours for the active metabolite desmethyldiazepam.”
A plain-language summary of the cited sources below. Informational only — not medical advice.
Diazepam is a benzodiazepine derivative that enhances GABAergic neurotransmission through positive allosteric modulation at GABA_A receptors, increasing postsynaptic chloride flux and producing anxiolytic, muscle-relaxant, anticonvulsant, and sedative effects. TGA-approved indications include management of anxiety disorders or short-term relief of anxiety symptoms, symptomatic relief in acute alcohol withdrawal, adjunctive treatment of reflex muscle spasm due to local trauma, and management of spasticity due to upper motor neuron lesions such as cerebral palsy and paraplegia, as well as athetosis and stiff-man syndrome.
Diazepam has an elimination half-life of 24–48 hours, with an active metabolite, desmethyldiazepam, that has a half-life of 40–100 hours, resulting in prolonged pharmacological activity and accumulation with repeated dosing. Oxidation is mediated by cytochrome P450 isozymes: formation of desmethyldiazepam mainly by CYP2C19 and CYP3A, and 3-hydroxy-diazepam and oxazepam by CYP3A. Contraindications include hypersensitivity to benzodiazepines, chronic obstructive pulmonary disease with incipient respiratory failure, severe respiratory insufficiency, severe hepatic impairment, sleep apnoea syndrome, myasthenia gravis, and CNS depressant dependence including alcohol, though an exception exists for management of acute withdrawal reactions. Serious adverse effects include cardiac failure including cardiac arrest, respiratory depression including respiratory failure, falls and fractures, paradoxical reactions such as restlessness, acute disorientation, aggressiveness, and other adverse behavioural effects, and physical dependence with chronic use at therapeutic doses, with discontinuation potentially resulting in withdrawal or rebound phenomena.
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Curated subset. The full adverse-effect list is in the TGA Product Information; click any citation above to open it.
“Oxidation of diazepam is mediated by cytochrome P450 isozymes; formation of desmethyldiazepam mainly by CYP2C19 and CYP3A and 3-hydroxy-diazepam (temazepam) and oxazepam by CYP3A.”