Opioid, sedative and tobacco use disorders: the AU general practice approach

Substance use disorders — treatable, common, and often under-addressed

Tobacco, opioid and sedative use disorders together represent some of the most prevalent and preventable sources of morbidity and mortality in Australian general practice. AIHW data show daily tobacco smoking in around 10% of Australian adults, accounting for approximately 21,000 deaths per year — still the single largest cause of preventable death. Opioid-related deaths exceed 1,000 per year, with prescription opioids and benzodiazepines together representing a larger burden than illicit heroin. Benzodiazepine dependence is quietly endemic, often iatrogenic, and frequently unaddressed.

These are not failures of willpower — they are recognised DSM-5 substance use disorders (SUD) meeting criteria when two or more of 11 diagnostic features are present. Modern treatment is highly effective, particularly for opioid use disorder, where opioid agonist treatment (OAT) has transformed mortality outcomes. The GP is positioned to identify, initiate treatment, monitor, and maintain long-term recovery.

A. Core clinical — the AU general-practice framework

Assessment

Before prescribing any controlled substance — opioid, benzodiazepine, gabapentinoid, or stimulant — check the real-time prescription monitoring system for your jurisdiction: SafeScript (Victoria), PRoDUR (NSW), QScript (Queensland), ScriptCheck (South Australia). These systems are mandatory in most jurisdictions and reveal concurrent prescribing from multiple prescribers, the leading driver of pharmaceutical opioid harm.

A structured assessment covers:

• Substance history — which substances, route of administration, frequency, quantity, duration, injection practices, overdose history
• Dependence features — DSM-5 SUD criteria: tolerance, withdrawal, loss of control, continued use despite harm, craving, role failure, social impact
• Mental health — depression, anxiety, PTSD, BPD, psychosis; comorbidity is the rule, not the exception
• Pain — distinguish chronic pain from opioid use disorder, which frequently co-occur; see eTG Chronic Pain
• Social circumstances — housing, employment, family, child welfare concerns
• Infection risk — for injecting drug use: hepatitis B, hepatitis C, HIV; abscesses, endocarditis, wound botulism

Key screening tools:

• ASSIST (Alcohol, Smoking and Substance Involvement Screening Test) — brief validated screening across all substances
• Fagerström Test for Nicotine Dependence — score ≥6 = high dependence; guides NRT dosing
• AUDIT-C — brief alcohol screen

Investigations:

• FBC, UEC, LFT, hepatitis B (HBsAg, anti-HBc), hepatitis C (anti-HCV), HIV testing for IV drug use
• ECG if considering methadone (QT prolongation risk with item 11707)
• Pregnancy test
• Urine drug screen (UDS) per local protocol

Opioid use disorder (OUD) — opioid agonist treatment

OAT is the gold standard for opioid use disorder. Sordo et al. (BMJ 2017) established in a large meta-analysis that OAT significantly reduces all-cause mortality and opioid-related mortality compared with periods off treatment.

Methadone — full μ-opioid agonist; starting dose 20–60 mg daily with supervised dispensing; titrated to 60–120 mg. Takeaway doses earned with demonstrated stability. QT prolongation risk — baseline ECG and annual monitoring. State-based specialist prescriber authorisation is required for initiation; GP shared care after stabilisation per state AOD regulations.

Buprenorphine-naloxone (Suboxone) — partial agonist plus naloxone (deters injection of dissolved product); 4–32 mg daily sublingual or buccal film; lower overdose risk than methadone due to ceiling on respiratory depression; preferred for many patients.

Long-acting injectable buprenorphine (LAI buprenorphine) — Sublocade (monthly subcutaneous) and Buvidal (weekly or monthly subcutaneous) — eliminate the daily dispensing burden, reduce diversion, and improve adherence. Lintzeris et al. (MJA 2024) found approximately half of Australian buprenorphine recipients are now on depot formulations. All OAT agents are PBS listed as Section 100 Highly Specialised Drugs for opioid dependence.

Naltrexone — pure antagonist; 50 mg oral daily or monthly IM. For highly motivated, abstinent patients only. Oral naltrexone is PBS Authority Required; Vivitrol (long-acting IM) is not currently PBS-listed for OUD in Australia.

Take Home Naloxone — The Take Home Naloxone Program provides free naloxone without a prescription from pharmacies nationwide. Nasal spray (Nyxoid 1.8 mg) and IM injection (Prenoxad). Offer naloxone and overdose education to every patient with OUD, and their household members.

Withdrawal management: mild to moderate opioid withdrawal can be managed outpatient with symptomatic medications (clonidine, lofexidine, ondansetron, loperamide, paracetamol, NSAIDs). Buprenorphine induction during withdrawal is preferred in most cases as it transitions smoothly to OAT.

Sedative use disorder — benzodiazepine and Z-drug dependence

Benzodiazepine dependence is often iatrogenic — developing from prescribed treatment of anxiety or insomnia, frequently without an end date or review. Physical dependence develops within weeks to months of regular dosing.

Tapering principles per eTG Addiction and RACGP prescribing guidance:

• Taper slowly — typically no more than 10% dose reduction every two to four weeks. Long-term users (10+ years) may require reductions of 5% every four to six weeks or slower.
• Convert short-acting agents (alprazolam, oxazepam, temazepam) to equivalent diazepam for smoother tapering.
• Never abruptly cease long-term benzodiazepine — withdrawal seizures and delirium are serious, potentially fatal complications.
• Address anxiety or insomnia driving use: CBT-I for insomnia, CBT/SSRI/SNRI for anxiety disorder. See eTG Psychotropic for antidepressant selection.

Real-time prescription monitoring must be checked at every script for S8 and monitored S4 medicines. Alprazolam was rescheduled to S8 in Australia in 2014, reducing prescribing and harm.

Tobacco use disorder

5As brief intervention at every GP visit: Ask (about current use), Assess (readiness and dependence level), Advise (clear personalised message about benefits of quitting), Assist (pharmacotherapy + Quitline referral), Arrange (follow-up at one week, four weeks, 12 weeks).

Pharmacotherapy per RACGP smoking cessation guidelines:

• Combination NRT — 24-hour patch (21 mg / 14 mg / 7 mg) plus short-acting form (2 mg or 4 mg lozenge, gum, inhaler, or mouth spray). Cochrane evidence confirms combination is more effective than single NRT.
• Varenicline (Champix) — most effective single agent; approximately three times the quit rate of placebo. Start 1 week before quit date; 12-week PBS course (Authority Required, Streamlined), with further 12-week PBS extension with documented response and Quitline/clinician contact — up to 24 weeks per year per NPS MedicineWise. The boxed warning for neuropsychiatric events was largely refuted by EAGLES (NEJM 2016).
• Bupropion (Zyban) — alternative; PBS for up to nine weeks; avoid in epilepsy, eating disorder, abrupt alcohol withdrawal.
• Quitline 13 7848 — free, evidence-based telephone counselling; My QuitBuddy app. Significantly improves quit rates when combined with pharmacotherapy.

B. Evidence — what works and what does not

Opioid agonist treatment: the evidence is unambiguous

Sordo et al. (BMJ 2017) pooled 19 studies in a systematic review and meta-analysis, demonstrating that time on OAT is associated with substantially lower all-cause mortality compared with time off treatment. Importantly, the period immediately after ceasing OAT carries the highest overdose risk — tolerance drops while craving remains, making illicit use after a gap acutely dangerous.

Long-acting injectable buprenorphine improves treatment retention and reduces diversion compared with sublingual formulations. Lintzeris et al. (MJA 2024) documented the rapid uptake of depot buprenorphine in Australia, with approximately 50% of buprenorphine recipients now on long-acting formulations.

Abstinence-only approaches without OAT have substantially worse outcomes than OAT — higher relapse rates, much higher mortality risk.

Varenicline: effective and safe in mental health populations

The landmark EAGLES trial (NEJM 2016) — 8,000 participants including those with psychiatric disorders — found no significant increase in moderate-to-severe neuropsychiatric adverse events with varenicline versus placebo. This effectively refuted the previous boxed warning. Varenicline can be used in patients with depression, anxiety, PTSD and schizophrenia with appropriate monitoring. Smoking cessation itself improves long-term mental health outcomes.

Benzodiazepine: effective for acute, harmful long-term

Benzodiazepines are rapidly effective for acute anxiety and acute alcohol withdrawal but are poorly suited to long-term anxiety or insomnia management. Tolerance develops within weeks. Cognitive impairment, falls, MVA risk, and dependence accumulate with long-term use. The evidence base for slow tapering plus CBT is robust; eTG Addiction provides the current AU reference standard.

C. Managing comorbidities and special clinical scenarios

Hepatitis C in injecting drug use

Direct-acting antiviral (DAA) therapy for hepatitis C is now PBS-accessible without specialist restriction — glecaprevir/pibrentasvir (Maviret, 8 weeks, pangenotypic) or sofosbuvir/velpatasvir (Epclusa, 12 weeks). People who inject drugs have the same treatment eligibility and outcomes as other populations. Cure of hepatitis C is achievable in people on OAT. Vaccinate against hepatitis B if non-immune.

Pregnancy and opioid use disorder

OAT (methadone or buprenorphine; buprenorphine-naloxone has accumulating safety data in pregnancy) should be continued in pregnant women with OUD — the risks of untreated opioid use disorder to mother and foetus far exceed those of continued OAT. Neonatal abstinence syndrome (NAS) is expected and manageable with perinatal addiction service input. Avoid abrupt withdrawal in pregnancy.

Smoking cessation in pregnancy: cessation is the highest priority. NRT (preferably intermittent forms — lozenge or gum — over patch) is preferred if pharmacotherapy is needed. Avoid varenicline and bupropion in pregnancy.

Real-time prescription monitoring

SafeScript, PRoDUR (NSW), QScript (Qld), ScriptCheck (SA) must be checked before prescribing every controlled drug. Clinical decision support alerts for concurrent opioid-benzodiazepine co-prescribing, multiple prescribers, and dose thresholds are built into these systems. Failure to check when prescribing a controlled drug is a prescribing quality concern.

D. Australian operations

MBS items:

• Standard consults 23 / 36 / 44 — use longer items for structured substance assessment
• Mental Health Care Plan 2715 / 2717 — for comorbid depression, anxiety, PTSD (common)
• Focused Psychological Strategies (GP FPS-trained) 2721 / 2723 — requires FPS training
• GPCCMP 965 / 967 — chronic SUD qualifies for care plan
• ECG 11707 — pre-methadone and annual monitoring
• ATSI Health Assessment 715; 75+ assessment 705; 45–49 701
• Practice nurse 10997

PBS:

• OAT (methadone, buprenorphine-naloxone, Sublocade, Buvidal) — Section 100 Highly Specialised Drugs; state prescribing authorisation required
• Naltrexone — PBS Authority Required
• Naloxone (Nyxoid nasal spray, Prenoxad IM) — Take Home Naloxone Program: free, no prescription
• Varenicline (Champix) — Authority Required (Streamlined); 12 weeks initial + further 12-week extension
• Bupropion (Zyban) — PBS smoking cessation, up to 9 weeks per year
• NRT — PBS-subsidised for ATSI, mental illness, and concession card holders; OTC otherwise

Crisis and AOD support services:

• DirectLine (Vic) 1800 888 236
• ADIS (NSW) 1800 250 015
• Counselling Online
• Lifeline 13 11 14
• Beyond Blue 1300 22 4636
• 13YARN 13 92 76 (First Nations)
• Open Arms (veterans and families) 1800 011 046
• PANDA (perinatal mental health) 1300 726 306

E. Special populations

Adolescents and young people: adolescent vaping is a significant and growing public health issue. Nicotine addiction is establishing in young people who would otherwise not have smoked. Ask about vaping at every adolescent health visit. Support cessation using NRT (where appropriate for age), brief motivational interviewing, and referral to youth-specific services.

Older adults and benzodiazepine use: long-term benzodiazepine prescribing in older adults causes falls, fractures, delirium, and cognitive impairment. Every medication review should flag benzodiazepines and Z-drugs in patients over 65 for slow taper. The Beers Criteria (AGS) and STOPP criteria list all benzodiazepines as potentially inappropriate in older adults. Engage patients with an honest conversation about the risks and offer a structured, supported taper.

First Nations Australians: tobacco smoking rates in Aboriginal and Torres Strait Islander communities are approximately three times the general population rate. ATSI Health Assessment 715, tailored culturally safe cessation support, NRT subsidised on PBS for ATSI peoples, and partnership with ACCHOs are the appropriate pathways. 13YARN (13 92 76) provides 24-hour crisis support from Aboriginal and Torres Strait Islander people.

Veterans: DVA Gold and White Card covers SUD-related care. Open Arms (Veterans and Families Counselling) 1800 011 046 provides 24/7 free counselling.

When to escalate

• Emergency / same day — opioid overdose: naloxone, 000, BLS; IV opioid and benzo co-overdose; severe withdrawal complications (seizures, delirium, arrhythmia); severe psychiatric crisis; pregnancy with active opioid use requiring specialist perinatal care
• Urgent (within days) — complex polysubstance use with medical instability; suspected severe psychiatric comorbidity; pregnancy with untreated OUD; IV drug use with acute infection (endocarditis, abscess, septic arthritis)
• Routine — OAT initiation requiring specialist prescriber authorisation; complex pain management with opioid use; pulmonary or cardiovascular consequences of long-term tobacco use; alcohol use disorder (see separate article)

What this article is and is not

This is general health information based on current Australian guidelines — RACGP Prescribing Drugs of Dependence, RACGP Supporting Smoking Cessation, eTG Addiction, AMH, TGA vaping reforms, Take Home Naloxone Program, and key published trials. It is not personal medical advice and does not substitute for individual clinical assessment. Decisions about specific pharmacotherapy, dosing, and OAT prescribing require your own GP and, where indicated, specialist addiction medicine involvement.

For support: Quitline 13 7848, Counselling Online, Take Home Naloxone Program, HealthDirect — Drug and alcohol services. For crisis: Lifeline 13 11 14, 13YARN 13 92 76, Beyond Blue 1300 22 4636.

---

Sources cited

1. RACGP — Supporting smoking cessation
2. RACGP — Prescribing drugs of dependence in general practice
3. eTG Addiction
4. Australian Medicines Handbook
5. Take Home Naloxone Program
6. TGA — Vaping hub: October 2024 reforms
7. NPS MedicineWise — Varenicline (Champix) extended PBS listing
8. Quitline 13 7848
9. Counselling Online
10. AIHW — Tobacco smoking in Australia
11. Sordo L et al. — OAT and mortality (BMJ 2017)
12. Lintzeris N et al. — Depot buprenorphine in Australia (MJA 2024)
13. Anthenelli RM et al. — EAGLES: varenicline neuropsychiatric safety (NEJM 2016)
14. SafeScript Victoria
15. PBS