Mysimba Tablets
Mysimba (naltrexone/bupropion) is a prescription oral medication for weight management in adults with obesity or overweight with weight-related conditions. This combination therapy is available through Chemist Doctor's regulated online service following a consultation with UK-licensed clinicians.
You must complete a short online consultation so that our prescriber can ensure that the treatment is suitable for you.
| Product Name: | Mysimba |
|---|---|
| Manufacturer: | Orexigen Therapeutics |
| Active Ingredients: | Naltrexone HCl & Bupropion HCl |
| Administration: | Oral |
| Presentation: | Prolonged-release tablets |
| Available Strength: | 8mg/90mg |
| Prescription Required: | Yes |
| Dosage: | Twice daily after 4-week titration |
| Suitable for pregnancy? | No |
| Use with alcohol: | Avoid or limit consumption |
| Dose | Package | Price |
|---|---|---|
| 8mg/90mg | 112 Tablets | £109.99 |
Dosing Schedule:
|
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| This treatment requires an online consultation for review by our medical team. The decision to supply the specific treatment and quantity requested will be based on whether our medical team are satisfied that it will be safe, appropriate, and effective. | ||
Table of Contents
- What is Mysimba?
- What is Mysimba Used For?
- Before Using Mysimba
- Mysimba Contraindications
- Special Population Considerations
- Mysimba and Other Medicines
- Pregnancy & Breastfeeding
- Driving & Machine Operation
- Mysimba Ingredients
- How to Take Mysimba Tablets
- Mysimba Dosage Guidelines
- Administration Instructions
- Missed Dose Management
- Overdose Information
- Mysimba Side Effects
- How to Store Mysimba
- Mysimba Pack Information
- Mysimba FAQs
What is Mysimba?
Mysimba contains naltrexone and bupropion in a prolonged‑release tablet. It is a prescription weight‑management medicine for adults with a BMI ≥30 kg/m², or ≥27 kg/m² with weight‑related conditions. It works on brain pathways that regulate hunger and food reward.
What is Mysimba Used For?
Mysimba is indicated as an adjunct to:
- Reduced‑calorie diet
- Increased physical activity
Approved Patient Groups
| Patient Group | BMI Requirements | Additional Criteria |
|---|---|---|
| Adults (≥18 years) | BMI ≥30 kg/m² or BMI 27–29.9 kg/m² |
With weight‑related comorbidities (e.g., type 2 diabetes, controlled hypertension, dyslipidaemia) |
Important Safety Notice:
Stop treatment and seek medical help if you experience:
- Seizure activity (fits)
- Severe allergic reaction (swelling, wheeze, hives)
- Severe or rapidly worsening rash
- Thoughts of self‑harm
Before Using Mysimba
Essential considerations before starting:
Medical History Assessment
- Blood pressure (exclude uncontrolled hypertension)
- History of seizures, head trauma, or brain tumour
- Mood disorders (including bipolar disorder) and current psychiatric symptoms
- Current or recent opioid use or dependence
- Eating disorders (bulimia or anorexia nervosa)
- Hepatic or renal impairment
- Alcohol or sedative withdrawal risk
Baseline & Ongoing Monitoring
- Blood pressure and pulse (baseline and periodically)
- Weight and percentage weight‑loss review at 16 weeks
- Mental health check‑ins (mood/suicidality)
- Renal and hepatic function when clinically indicated
Mysimba Contraindications
Do not use if any apply:
- Allergy to naltrexone, bupropion, or excipients
- Uncontrolled hypertension
- Seizure disorder or prior seizures
- Current or recent alcohol/benzodiazepine withdrawal
- Bipolar disorder
- Eating disorders (bulimia/anorexia)
- Chronic opioid use / acute opioid withdrawal
- MAOI use within the last 14 days
- Severe hepatic impairment or end‑stage renal disease
- Pregnancy or breastfeeding
Special Warnings
| Condition | Precaution |
|---|---|
| Hypertension or CVD | Monitor BP/HR regularly; consider alternatives if uncontrolled |
| Psychiatric history | Monitor mood; stop if suicidal ideation emerges |
| Seizure risk factors | Avoid concomitant medicines that lower seizure threshold |
Special Population Considerations
Elderly Patients (≥65 years)
- Use with caution; titrate carefully
Renal Impairment
- Mild–moderate: caution with monitoring
- Severe/ESRD: contraindicated
Hepatic Impairment
- Mild–moderate: use with caution
- Severe: contraindicated
Paediatrics
- Not recommended under 18 years
Mysimba and Other Medicines
Significant interactions requiring avoidance or close monitoring:
High‑Risk Combinations
- MAOIs: Contraindicated (minimum 14‑day washout)
- Opioids (e.g., codeine, tramadol, morphine): Antagonised by naltrexone; risk of withdrawal
- Medicines lowering seizure threshold: e.g., antipsychotics, systemic steroids, quinolones, tramadol
- SSRIs/SNRIs/tricyclics: Increased seizure and serotonin‑related risks; monitor
Other Considerations
- CYP2B6 interactions (bupropion substrate/inhibitor): review co‑medications
- Alcohol: May increase adverse CNS effects; limit or avoid
Pregnancy & Breastfeeding
Pregnancy
- Not recommended; discontinue immediately if pregnancy occurs
- Use effective contraception during treatment
Breastfeeding
- Contraindicated during breastfeeding
Driving & Machine Operation
- May cause dizziness or drowsiness
- Do not drive or operate machinery if affected
Mysimba Ingredients
Active Substances
- Naltrexone hydrochloride (8 mg)
- Bupropion hydrochloride (90 mg)
Excipients (summary)
| Ingredient | Note |
|---|---|
| Lactose monohydrate | Contains lactose |
| Other tablet excipients | See Patient Information Leaflet for full list |
How to Take Mysimba Tablets
General Advice
- Take with food to reduce nausea
- Swallow tablets whole; do not crush, split, or chew
- Avoid taking doses near bedtime to reduce insomnia
Weekly Titration
- Week 1: 1 tablet in the morning
- Week 2: 1 tablet morning & 1 tablet evening
- Week 3: 2 tablets morning & 1 tablet evening
- Week 4 onwards: 2 tablets morning & 2 tablets evening (max dose)
Mysimba Dosage Guidelines
Standard Schedule
| Treatment Week | Daily Regimen | Notes |
|---|---|---|
| Week 1 | 1 tablet AM | Start dose |
| Week 2 | 1 tablet AM + 1 tablet PM | With food |
| Week 3 | 2 tablets AM + 1 tablet PM | With food |
| Week 4+ | 2 tablets AM + 2 tablets PM | Maximum dose |
Assessing Response
- Reassess at 16 weeks: discontinue if <5% weight loss at maintenance dose
Administration Instructions
To optimise tolerability and efficacy:
- Take doses with meals
- Avoid alcohol or keep intake minimal
- Do not exceed the prescribed dose
Missed Dose Management
General Principles
- Do not double doses
- If close to the next dose, skip the missed dose and continue as scheduled
Practical Guidance
| Situation | Action |
|---|---|
| Forgotten earlier in the day | Take when remembered if not near next dose |
| Near the next scheduled dose | Skip and resume regular schedule |
Overdose Information
Symptoms
- Seizures, confusion, hallucinations
- Fast or irregular heartbeat
- Severe nausea/vomiting
Management
- Seek urgent medical attention (call NHS 111 / attend A&E)
- Bring medication packaging
- Supportive care as directed by clinicians
Possible Side Effects
Very Common (more than 1 in 10 people)
- Nausea
- Constipation
- Headache
Common (1 in 10 to 1 in 100 people)
- Anxiety, insomnia
- Dizziness, tremor
- Dry mouth, sweating, fatigue
- Rash
Serious Side Effects
| Effect | Frequency | Action Required |
|---|---|---|
| Seizures | Rare | Stop treatment; urgent assessment |
| Severe skin reactions | Rare | Emergency evaluation |
| Suicidal thoughts/behaviour | Not known | Stop and seek immediate help |
| Raised blood pressure/heart rate | Common | Monitor; consider discontinuation |
How to Store Mysimba
Storage Conditions
- Store below 25°C
- Keep in original packaging to protect from moisture
- Keep out of the sight and reach of children
Disposal
- Return unused tablets to a pharmacy
- Do not dispose of medicines via household waste
Pack Information
Pack Sizes
- 112 prolonged‑release tablets (typical pack)
Components
- Blister packs of tablets
- Patient Information Leaflet
Appearance
- Film‑coated prolonged‑release tablets
Where Can I Buy Mysimba Online in the UK
Secure Mysimba Prescription & Next‑Day Delivery Service
Order Mysimba with confidence through our UK‑registered medical prescribers, who review all requests within 4 working hours. We aim to dispatch approved orders placed before 3pm for next‑day tracked delivery.
Our service combines transparent pricing with MHRA safety standards, ensuring your medication is dispensed through GPhC‑registered pharmacies. Every purchase includes discreet packaging and a GDPR‑compliant consultation process.
Our clinical team ensures:
- Comprehensive medical history review
- BMI and comorbidity assessment
- Drug interaction checks
- Personalised dosing guidance
Always consult your GP before starting weight management treatment. Not recommended for children under 18.
Mysimba (Naltrexone/Bupropion) FAQs
How effective is Mysimba?
In clinical studies, a significant proportion of patients achieved ≥5% weight loss at 56 weeks alongside diet and exercise. Your results will vary based on adherence and lifestyle factors.
Can I drink alcohol while taking Mysimba?
Limit or avoid alcohol. It can increase side effects (e.g., dizziness) and seizure risk and adds empty calories that may hinder weight loss.
Will Mysimba affect my ability to drive?
It may cause dizziness or drowsiness. If affected, do not drive or operate machinery.
How long should I take Mysimba?
Assess progress after 16 weeks on the maintenance dose. If you have not lost at least 5% of your starting weight, treatment should be reconsidered.
Can I use Mysimba with other weight‑loss medicines?
Do not combine with other prescription weight‑loss medicines unless a clinician advises; interaction and safety concerns may arise.
Do I need to diet and exercise as well?
Yes. Mysimba must be combined with calorie restriction and increased physical activity for best results.
How soon will I see results?
Early changes are often seen within 4–8 weeks of dose escalation. Reassess formally at 16 weeks.
Related Guides
Medical Content Manager
Nabeel is a co-founder, and medical content manager of Chemist Doctor. He works closely with our medical team to ensure the information is accurate and up-to-date.
Medical Doctor
Dr. Talal is a GMC registered doctor and medical reviewer at Chemist Doctor. He ensures clinical accuracy and reliability across health content.
Medical Director
Usman is a co-founder, and medical director of Chemist Doctor. He leads the organisation's strategic vision, bridging clinical and operational priorities.
Review Date: 01 May 2025
Next Review: 04 December 2025
Published on: 01 May 2025
Last Updated: 02 May 2025
Getting your medication is quick and easy with our simple 4-step process:
Start Consultation
Complete our brief health questionnaire about your medical history and current health.
Medical Review
UK-registered clinicians review your consultation for safe prescribing.
Pharmacy Processing
If approved, our partner pharmacy prepares your medication.
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What does the online consultation involve?
You'll answer questions about your medical history and current health to ensure safe prescribing. Honest responses are vital for your safety.
How do I reorder medication?
Use the login details emailed after your first order to access your account and reorder.
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Clinicians may contact you via your account's chat portal to discuss your treatment. Respond securely within your account.
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Only with your consent. We recommend updating your GP directly for seamless care.
We offer two reliable delivery options to suit your needs:
| Service Type | Delivery Speed | Order Cut-off | Carrier |
|---|---|---|---|
| Standard Delivery | 2-3 business days | No cut-off | Royal Mail |
| Premium Next-Day Delivery | Next business day | 3 PM weekdays | Royal Mail 24 |
Next-day delivery guarantee applies to orders approved before 3 PM to these regions:
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Service Restrictions: We currently cannot deliver to: Republic of Ireland, Continental Europe, USA, or Canada
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Deliveries occur Monday–Friday only. We do not ship on weekends or UK bank holidays.
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Declined orders are not charged. Card authorisations release funds within 3–5 days (contact your bank for details).
Can I return prescription medication?
No. UK law prohibits returns of dispensed prescription treatments for safety reasons.
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