For family members and guardians
A plain-language summary of the cited sources below. Informational only — not medical advice.
Diazepam belongs to a group of medicines called benzodiazepines. It works by boosting a natural calming chemical in the brain called GABA, which helps quiet down overactive nerve signals. Your family member might be taking it for anxiety, muscle spasms caused by injury or conditions like cerebral palsy, or sometimes to manage severe alcohol withdrawal symptoms. The medicine and its active by-products can stay in the body for a long time—diazepam itself typically lasts one to two days, and one of its breakdown products can remain active for several days after that, which means effects can build up over time.
Common side effects you might notice include headaches, trouble sleeping, muscle aches, diarrhoea, or sometimes an increase in anxiety rather than a decrease. More serious but less common effects can include seizures, confusion, seeing or hearing things that aren't there, or changes in blood cell counts. The medicine isn't suitable for people with certain lung or breathing problems, severe liver disease, sleep apnoea, myasthenia gravis, or for those dependent on alcohol or other sedatives (except when it's being used specifically to manage withdrawal). It can also interact with other medications that are broken down by the same liver enzymes, so it's important that all prescribers know what else your family member is taking.
Because diazepam has a sedating effect and can reduce a person's ability to make decisions or move freely, a Behaviour Support Practitioner will review whether it's being used in a way that might function as a chemical restraint—that is, whether its calming effect is being relied upon to manage behaviour rather than to treat a diagnosed medical condition like anxiety or muscle spasm.
For prescribers
A plain-language summary of the cited sources below. Informational only — not medical advice.
Diazepam is a long-acting benzodiazepine that enhances GABAergic inhibition through positive allosteric modulation of GABA_A receptors, increasing chloride flux and central nervous system depression. Its extended elimination half-life (24–48 hours for the parent compound, 40–100 hours for the active metabolite desmethyldiazepam) means steady-state pharmacodynamic effects accumulate over days and persist well beyond cessation. Metabolism is hepatic via CYP2C19 and CYP3A4, yielding multiple active metabolites including temazepam and oxazepam; co-administration of CYP inhibitors (azole antifungals, macrolides, protease inhibitors) or inducers (carbamazepine, rifampicin) will alter exposure significantly. Standard indications include short-term anxiolysis, acute alcohol withdrawal, and relief of skeletal muscle spasm secondary to upper motor neuron lesions or local musculoskeletal pathology. Contraindications are absolute in respiratory compromise (COPD with incipient failure, sleep apnoea), severe hepatic impairment, and myasthenia gravis.
When diazepam is prescribed for a participant with intellectual disability or acquired brain injury, particularly where the documented purpose relates to managing behaviours of concern rather than a discrete DSM/ICD anxiety disorder or neurological spasticity, the prescription may meet the NDIS definition of a restrictive practice (chemical restraint). This triggers documentation and oversight requirements under the NDIS Quality and Safeguards Commission framework, including registration on a behaviour support plan, six-monthly review by the participant's behaviour support practitioner, and in some jurisdictions prior approval by a senior practitioner. The BSP contacting you is seeking confirmation of the prescribed indication, the clinical reasoning supporting ongoing use, and the monitoring schedule you have in place—this is a statutory compliance function, not a challenge to your prescribing. Clear documentation that the indication is a recognised medical disorder (e.g., generalised anxiety disorder with formal diagnostic criteria met, alcohol withdrawal protocol, spasticity from cerebral palsy) and that regular review for deprescribing is occurring will satisfy the framework's intent while preserving clinical autonomy.
Mechanism & pharmacology
“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.”
“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.”
TGA-approved indications
- Management of anxiety disorders or for the short-term relief of the symptoms of anxiety↗TGA PIT1✓
- In acute alcohol withdrawal, diazepam may be useful in the symptomatic relief of acute agitation, tremor, impending or acute delirium tremens and hallucinosis↗TGA PIT1✓
- relief of reflex muscle spasm due to local trauma (injury, inflammation) to muscles, bones and joints↗TGA PIT1✓
- combat spasticity due to upper motor neuron lesions such as cerebral palsy and paraplegia, as well as in athetosis and stiff-man syndrome↗TGA PIT1✓
PBS-subsidised indications
- Chronic spasticity↗PBST2✓
Show clinical criteria
Chronic spasticity Clinical criteria: Population criteria: Patient must be under 18 years of age.
- Anxiety↗PBST2✓
Show clinical criteria
Anxiety Clinical criteria: Clinical criteria: Patient must be receiving palliative care. Note: No increase in the maximum number of repeats may be authorised.
Adverse effects
Common (top 5)
- headache↗TGA PIT1✓
- diarrhoea↗TGA PIT1✓
- muscle pain↗TGA PIT1✓
- insomnia↗TGA PIT1✓
- extreme anxiety↗TGA PIT1✓
Serious
- convulsions↗TGA PIT1✓
- delirium↗TGA PIT1✓
- hallucinations↗TGA PIT1✓
- psychosis↗TGA PIT1✓
- blood dyscrasias↗TGA PIT1✓
Curated subset. The full adverse-effect list is in the TGA Product Information; click any citation above to open it.
Contraindications
- Patients with known hypersensitivity to benzodiazepines, diazepam or any of the excipients.↗TGA PIT1✓
- Patients with chronic obstructive pulmonary disease with incipient respiratory failure.↗TGA PIT1✓
- Patients with severe respiratory insufficiency.↗TGA PIT1✓
- Patients with severe hepatic impairment as benzodiazepines may precipitate hepatic encephalopathy.↗TGA PIT1✓
- Patients with sleep apnoea syndrome.↗TGA PIT1✓
- Patients with myasthenia gravis.↗TGA PIT1✓
- Patients with CNS depressant dependence including alcohol. An exception to the latter is the management of acute withdrawal reactions.↗TGA PIT1✓
Regulated practice context
A plain-language summary of the cited sources below. Informational only — not medical advice.
- Regulator framework: Diazepam prescribed to influence behaviour falls under the NDIS Quality and Safeguards Commission's regulated restrictive practices framework as chemical restraint. Implementing providers must hold state/territory authorisation, engage a specialist behaviour support provider, lodge the resulting behaviour support plan with the Commission, and submit monthly reports on the practice's use.↗NDIS CommissionT2✓
- Statutory anchor: the regulated-restrictive-practices framework applied to Diazepam when prescribed as chemical restraint sits under the National Disability Insurance Scheme Act 2013, the parent statute under which the NDIS (Restrictive Practices and Behaviour Support) Rules 2018 are made and the NDIS Quality and Safeguards Commission operates.↗NDIS ActT2✓
- Commonwealth clinical-quality overlay: Diazepam use in people with cognitive disability or impairment is governed by the ACSQHC Psychotropic Medicines in Cognitive Disability or Impairment Clinical Care Standard (2024). The Standard's eight quality statements require thorough assessment, non-medication strategies tried first, individualised behaviour planning, clear treatment goals, and regular review with deprescribing where appropriate — applying across all settings where the person receives care.↗ACSQHC Psychotropic Medicines Clinical Care StandardT2✓
Jurisdictional framework
Select your state to see jurisdictional framework, reporting obligations, and authority links. Substance information above is the same in every state.
Restrictive practice framework
ACT2 citations
- In the Australian Capital Territory, use of Diazepam as chemical restraint is regulated by the Senior Practitioner Act 2018 (ACT), which establishes the Office of the Senior Practitioner with independent oversight across disability services, education, residential care, and child protection. A Positive Behaviour Support Plan must justify the practice as the least-restrictive option, with active reduction strategies. The ACT framework's stated aim is the reduction and elimination of restrictive practices.
- Statutory anchor: Diazepam use as chemical restraint in the ACT is regulated by the Senior Practitioner Act 2018 (ACT). The Act's stated object is the reduction and elimination of restrictive practices and it applies broader-than-NDIS oversight: disability services, education, residential care, and child protection all sit within scope.
NSW1 citation
- In New South Wales, use of Diazepam as chemical restraint by a registered NDIS provider must be authorised under the NSW Restrictive Practices Authorisation framework administered by the Department of Communities and Justice (DCJ). Authorisation requires a Behaviour Support Plan documenting the practice, evidence that it is the least-restrictive option, and a documented reduction strategy. Psychotropic medications used as restraint should be reviewed at least every six months by a medical practitioner and at least every twelve months by a psychiatrist.
NT1 citation
- In the Northern Territory, use of Diazepam as chemical restraint by a registered NDIS service provider requires authorisation by the NT Senior Practitioner via the Restrictive Practice Authorisation System administered by NT Health. Applications must include the Behaviour Support Plan, evidence of consultation with the participant and relevant others, particulars of the providers applying the practice, and a summary of every restrictive practice applied in the preceding 12 months.
QLD4 citations
- In Queensland, use of Diazepam as chemical restraint by funded disability service providers is governed by the Disability Services Act 2006 (Qld) and the positive behaviour support / restrictive practices framework administered by the Department of Families, Seniors, Disability Services and Child Safety. Authorisation must follow assessment by an appropriately qualified practitioner, a Positive Behaviour Support Plan, and the legislative tests of least-restrictive practice and reduction planning. Authorisation is granted per restrictive-practice type — separate authorisation is required for each.
- In Queensland, use of Diazepam as chemical restraint on an adult with disability requires consent from a restrictive-practices guardian appointed by the Queensland Civil and Administrative Tribunal (QCAT), or short-term approval by the chief executive of the relevant disability service while a Positive Behaviour Support Plan is being developed. The Office of the Public Guardian acts as substitute decision-maker where appointed. Use must be the least-restrictive option to prevent serious harm and is subject to reduction planning.
- Statutory anchor: substitute decision-making for Diazepam use as chemical restraint on adults with impaired capacity in Queensland is governed by the Guardianship and Administration Act 2000 (Qld). Chapter 5B Part 4 sets out QCAT's powers to appoint a restrictive-practices guardian and the Office of the Public Guardian's role as substitute decision-maker.
- Statutory anchor: Diazepam use as chemical restraint by funded disability service providers in Queensland is regulated by the Disability Services Act 2006 (Qld), Chapter 5B of which sets out the positive behaviour support and restrictive-practice authorisation framework. The PBSRP Reform Bill 2024 lapsed in October 2024; the existing framework remains in force.
SA2 citations
- In South Australia, use of Diazepam as chemical restraint is a Level 2 restrictive practice under the SA Restrictive Practices Authorisation Scheme (in force from 30 May 2022) and can only be authorised by the Senior Authorising Officer — Authorised Program Officers cannot approve chemical restraint. Authorisation requires a Behaviour Support Plan, advice from a Specialist Behaviour Support Practitioner, and consultation with the participant and their family. The scheme is administered by the Restrictive Practices Unit within the Department of Human Services.
- Statutory anchor: Diazepam use as chemical restraint in South Australia is regulated by the Disability Inclusion Act 2018 (SA), with the operative detail in the Disability Inclusion (Restrictive Practices — NDIS) Regulations 2021. Together they establish the two-tier authorisation scheme (Authorised Program Officer for Level 1, Senior Authorising Officer for Level 2 including chemical restraint) in force from 30 May 2022.
TAS2 citations
- In Tasmania, use of Diazepam as chemical restraint by a disability service provider requires authorisation by the Tasmanian Senior Practitioner under the Disability Rights, Inclusion and Safeguarding Act 2024 (Tas). The Senior Practitioner authorises, oversees, and reports on restrictive practice use in NDIS-funded and Department of Communities Services–funded disability services, with a statutory requirement to protect the rights of people subject to restrictive practices to the greatest extent possible.
- Statutory anchor: Diazepam use as chemical restraint by disability service providers in Tasmania is regulated by the Disability Rights, Inclusion and Safeguarding Act 2024 (Tas), which establishes the Tasmanian Senior Practitioner with statutory powers to authorise, oversee, and report on restrictive-practice use in NDIS-funded and Department of Communities Services–funded disability services.
VIC2 citations
- In Victoria, use of Diazepam as chemical restraint requires authorisation by the Victorian Senior Practitioner under the Disability Act 2006 (Vic). Authorisation must satisfy the legislative tests of necessity to prevent harm, least-restrictive option, and a documented reduction plan.
- Statutory anchor: Diazepam use as chemical restraint in Victoria is regulated by the Disability Act 2006 (Vic), Part 7 of which establishes the Senior Practitioner role and the regulated-restrictive-practice authorisation framework. The Act's tests of necessity, least-restrictive option, and reduction planning are statutorily binding.
WA1 citation
- In Western Australia, use of Diazepam as chemical restraint requires authorisation through a Quality Assurance Panel under the WA Department of Communities Authorisation of Restrictive Practices framework (effective 1 December 2020). The panel must include at least two decision-makers: a senior manager from the implementing provider and an independent NDIS Behaviour Support Practitioner external to that provider who did not write the Behaviour Support Plan. Unlike single-administrator state models, the panel decision is the authorisation.
The reasoning structure on this page is largely transferable to the parallel aged-care restrictive-practices framework administered by the Aged Care Quality and Safety Commission. The Commonwealth statute (Aged Care Act 1997) governs in place of the NDIS Rules; the medication-context analysis is otherwise the same.