Bupropion + Naltrexone: A Comprehensive Guide for Patients in Australia
Basic Product Information
| International Nonproprietary Names (INN) | Bupropion Hydrochloride + Naltrexone Hydrochloride |
|---|---|
| Common Australia Brand Names | Contrave® |
| ATC Code | A08AA62 |
| Available Forms & Strengths | Prolonged-release (modified, extended-release) film-coated tablets: 8 mg naltrexone hydrochloride + 90 mg bupropion hydrochloride |
| Manufacturers | iNova Pharmaceuticals (Australia) Pty Ltd |
| Prescription Status | Prescription-only medicine (Schedule 4; S4) |
Mechanism of Action
For Patients: Bupropion and naltrexone work together to help reduce hunger and curb food cravings. Bupropion acts on the brain’s reward and motivation centres (dopamine and noradrenaline pathways), while naltrexone blocks certain receptors involved in controlling appetite. By combining these effects, this medicine can help support healthy eating changes and sustained weight loss.
For Healthcare Professionals: Bupropion is a norepinephrine-dopamine reuptake inhibitor (NDRI), while naltrexone is an opioid receptor antagonist. Together, they synergistically activate the hypothalamic pro-opiomelanocortin (POMC) neurons and reduce inhibitory feedback mediated by β-endorphin action at the µ-opioid receptor, thus enhancing central appetite suppression and regulation of energy balance.
Pharmacokinetics
| Absorption | Both components are well absorbed orally. Bupropion has a bioavailability of approximately 5–20% due to first-pass metabolism. Naltrexone’s oral bioavailability is about 5–40%. |
|---|---|
| Metabolism | Bupropion is metabolised in the liver mainly by CYP2B6 to three active metabolites. Naltrexone is also hepatically metabolised, mainly to 6-β-naltrexol. |
| Elimination | Bupropion and its metabolites are eliminated primarily via urine, with some via faeces. Naltrexone and its metabolites are excreted renally. |
| Duration of Action | The elimination half-life of bupropion ranges from 20–37 hours; naltrexone’s terminal half-life is about 4–13 hours (naltrexol about 13 hours). The prolonged-release formulation supports once to twice daily dosing. |
Use in Everyday Life and Best Practices
In Australia, Bupropion + Naltrexone is prescribed as part of a comprehensive weight management program when diet and exercise alone have not achieved sufficient results. It is most suited to adults with a Body Mass Index (BMI) of ≥30 kg/m2 (obese), or ≥27 kg/m2 (overweight) plus weight-related health conditions such as type 2 diabetes, dyslipidaemia, pre-diabetes, or hypertension.
- Typical dose: Therapy starts at a low dose, gradually increasing to minimise side effects:
- Week 1: One tablet in the morning
- Week 2: One tablet in the morning, one in the evening
- Week 3: Two tablets in the morning, one in the evening
- Week 4 and onwards: Two tablets in the morning, two in the evening (total daily dose: 32 mg naltrexone + 360 mg bupropion)
- Swallow tablets whole—do not cut, crush, or chew.
- Weight loss should be regularly assessed; if you do not lose at least 5% of baseline weight by week 16, your doctor may recommend stopping the medicine.
- This medicine should always be used with a healthy eating plan and regular physical activity, considering common Australian dietary patterns (“Australian Guide to Healthy Eating”).
Dosing: Morning vs Evening
- Morning: Taking the first dose in the morning reduces the risk of sleep problems or insomnia, as bupropion can be stimulating for some people.
- Evening: If taking in the evening, aim for early evening (before 6pm) to reduce sleep interference.
- Best Practice: Take doses at the same times each day, spaced about 8 hours apart. Setting an alarm or incorporating with daily routines (e.g., breakfast and dinner) helps maintain consistency.
- Missed Dose: Skip if over 8 hours late—do not double the next dose.
Taking with Food or on an Empty Stomach
- It is preferable to take Bupropion + Naltrexone with food (a standard meal or snack, not a high-fat meal) to help reduce the likelihood of nausea and gastrointestinal side effects.
- Avoid taking with high-fat meals, as this can increase the risk of side effects.
- When integrating with the typical Australian diet, try to take with breakfast and dinner, in line with “Australian Guide to Healthy Eating” principles and standard meal times.
Interaction Warnings
| Food | High-fat meals may increase exposure to bupropion and naltrexone, raising side effect risks. |
|---|---|
| Alcohol | Avoid alcohol or limit intake—may increase risk of neuropsychiatric side effects, seizures, or mood changes. |
| Medications | Use caution with:
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Indications
| Indication | Official (TGA Approved) | Off-label/Other |
|---|---|---|
| Weight management in adults (BMI ≥30 kg/m2 or ≥27 kg/m2 with comorbidities) | ✔ | |
| Weight management in paediatric/adolescent populations | ✘ Not recommended | |
| Management of food cravings, binge eating | Can be considered off-label by specialist (with caution) | |
| Smoking cessation, depression | Individual components only; not combination |
Dosing According to Clinical Indications
| Population | Starting Dose | Titration | Maximum Dose |
|---|---|---|---|
| Adults | 1 tablet (8/90 mg) once daily in the morning (week 1) | Gradually increased by 1 tablet per week to reach 2 tablets twice daily (week 4 onwards) | 4 tablets daily (2 AM, 2 PM): 32 mg naltrexone + 360 mg bupropion |
| Elderly (≥65 years) | As per adults; caution with comorbidities and renal/hepatic function | Slower titration may be considered | Do not exceed adult maximum |
| Children/Adolescents | Not recommended; safety and efficacy not established | ||
| Renal or Hepatic Impairment | Use with caution or avoid; dose adjustment and close monitoring essential. Not recommended in severe hepatic/renal impairment. (Consult doctor/pharmacist before use.) | ||
Safety Profile & Side Effects
| Common | Less Common/Rare | Warnings |
|---|---|---|
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Guidelines for Proper Use (Australia)
- Always follow your doctor’s dosing instructions—never exceed the recommended dose.
- If you experience sudden mood changes, thoughts of self-harm, or severe neurological symptoms, call your doctor or emergency services immediately (triple zero – 000).
- Monitor blood pressure and pulse regularly—any significant rise should be reported to your GP.
- Do not consume opioid medications (including codeine-containing cold/flu remedies) while on this medicine. Inform all healthcare providers you are taking naltrexone before any surgery or pain treatment.
- Store tablets in a cool, dry place in their original packaging; keep out of reach of children.
- Tell your pharmacist or GP about all medicines and supplements you take.
- Australian community pharmacy consumers may access free medication reviews (“Home Medicines Review” service)—ask your pharmacist.
Alternative Treatment Options (Australia)
- Liraglutide (Saxenda®)
Type: GLP-1 receptor agonist, daily injection.
Pros: Effective for weight loss in many patients; beneficial for those with diabetes.
Cons: Injectable, not oral; gastrointestinal side effects common; only for specific criteria. - Semaglutide (Wegovy®, Ozempic®) (anticipated broader weight management approval)
Type: GLP-1 receptor agonist, weekly injection.
Pros: High weight loss efficacy; convenient weekly dosing.
Cons: Injectable, allocation prioritised for diabetes; supply variability. - Orlistat (Xenical®)
Type: Gastrointestinal lipase inhibitor.
Pros: Oral capsule; no central nervous effects.
Cons: Gastrointestinal side effects (oily stools); dietary fat must be limited; less effective. - Phentermine (Duromine®)
Type: Sympathomimetic amine.
Pros: Oral, effective for some patients.
Cons: Short-term only (up to 3 months); stimulant side effects; potential for abuse. - Non-pharmacological: “Better Health Channel” resources: dietitian support, exercise programs, psychological therapies.
- Comparative points: Only Contrave®, Saxenda®, and Xenical® are approved for longer-term weight management in Australia. GLP-1 analogues not always reimbursed; discuss options with your GP.
Legal, Registration, and Reimbursement Status in Australia
- Regulatory Agency: Therapeutic Goods Administration (TGA)
- Registration Status: Registered under ARTG (Australian Register of Therapeutic Goods)
- Prescription Requirements: Schedule 4 (S4)—must have a valid Australia prescription from a registered medical practitioner.
- Reimbursement Status: As of June 2024, Contrave® is not funded under the PBS (Pharmaceutical Benefits Scheme); private purchase only, except in specific clinical trials or hospital arrangements.
- Monitoring: Ongoing evaluation by the PBAC (Pharmaceutical Benefits Advisory Committee) and relevant research groups.
Latest Research and Clinical Guidance (2022–2025)
Recent reviews from the Medical Journal of Australia (2023) and the Australian Prescriber (2024) confirm that naltrexone/bupropion can be a safe and effective adjunct in selected adults with obesity, particularly where other pharmacological options are unsuitable. Efficacy data show average placebo-corrected weight loss of around 4–5% at 1 year, but sustained benefit requires ongoing lifestyle intervention.
Current guidelines (RACGP, 2022; Endocrine Society of Australia, 2023) recommend multi-modal support and noting the potential neuropsychiatric side effects. There is ongoing research into combination therapy with GLP-1 analogues and metabolic surgery, but as yet these approaches are not standard.
Reference literature:
- Colquitt JL, et al. "Pharmacological interventions for overweight or obesity," Cochrane Database Syst Rev. 2024.
- Sumithran P, Proietto J. "Pharmacotherapy for weight loss in adults," Med J Aust. 2023; 218(4):198-204.
- "Weight management – the latest guidance for GPs." Australian Prescriber, 2024; 47(1): 16–22.
Availability and Delivery in Australia
| Pack Size | Approximate Price (June 2024) | Delivery Times (Major Cities) |
|---|---|---|
| 112 tablets (4 weeks’ supply at maintenance dose) | $280–$340 (private script only; varies by pharmacy) | Sydney: Next business day Melbourne: Next business day Brisbane: 2 business days Perth: 3–4 business days Adelaide: 2 business days Hobart: 2–3 business days Regional/rural: 3–7 business days |
- Available via most community pharmacies and some online pharmacy services (Australian registered only).
- Always require a valid prescription—pharmacies may request GP letter and ID verification for online dispensing.
Frequently Asked Questions (FAQ)
- How soon will I notice weight loss with Bupropion + Naltrexone?
Weight loss usually starts within the first weeks but varies from person to person. Doctors assess effectiveness at 4 and 16 weeks; you should aim for at least a 5% reduction in baseline weight by week 16. - Can I drink alcohol while taking this medicine?
Alcohol should be limited as it can increase the risk of side effects, particularly seizures and mood changes. Heavy drinking should be avoided completely. - What happens if I miss a dose?
Take your next scheduled dose as usual. Do not double up or take extra; just continue with your regular dosing schedule. - Can I use Contrave® if I am also taking painkillers?
You must not use opioid painkillers while on naltrexone. Non-opioid pain medicines such as paracetamol or non-steroidal anti-inflammatory drugs (NSAIDs), like ibuprofen, are generally safe—always check with your GP or pharmacist. - Will Bupropion + Naltrexone affect my mental health?
In a small proportion of users, mood changes, anxiety, or even thoughts of self-harm can occur. If you notice any significant mood or behavioural changes, contact your doctor promptly.
For further guidance, contact your Australia GP, pharmacist, or visit the TGA and Healthdirect for trusted information on prescription medicines and healthy weight management.
