What is the recommended dosing of bupropion (Wellbutrin) and topiramate (Topamax) for a 28-year-old male with a history of diverticulitis, colostomy, and hernia who is seeking weight loss?

Dosing Bupropion and Topiramate for Weight Loss in a 28-Year-Old Male

Do not prescribe bupropion and topiramate together as separate medications—this combination significantly increases seizure risk and causes serious neuropsychiatric complications. 1

Critical Safety Issue: Avoid This Combination

The combination of bupropion with topiramate creates dangerous drug interactions that include:

• Increased seizure risk due to both medications lowering the seizure threshold 1
• Cognitive impairment with worsening concentration and memory problems 1
• Enhanced neuropsychiatric adverse effects including anxiety and panic attacks 1

Recommended Alternative Approaches

Option 1: FDA-Approved Phentermine/Topiramate ER (Qsymia) - Preferred Choice

Use the FDA-approved fixed-dose combination phentermine/topiramate ER instead of prescribing these as separate agents. 2

Dosing schedule:

• Week 1-2: Start 3.75 mg phentermine/23 mg topiramate ER once daily in the morning 2
• Week 3 onward: Increase to 7.5 mg/46 mg once daily 2
• Week 12 assessment: If <3% weight loss achieved, escalate to 11.25 mg/69 mg daily 2
• Maximum dose: 15 mg/92 mg daily if needed 2

Discontinuation criteria:

• Stop if <3% weight loss at 12 weeks on the 7.5/46 mg dose 2
• Stop if <5% weight loss at 12 weeks on the 15/92 mg dose 2

Expected weight loss: 9.8% total body weight loss at one year on the maximum dose 3, 4

Option 2: Bupropion/Naltrexone SR (Contrave) - Alternative Without Topiramate

If you prefer bupropion for its antidepressant properties, use the FDA-approved bupropion/naltrexone SR combination instead. 2

Dosing schedule:

• Week 1: 1 tablet (8 mg naltrexone/90 mg bupropion) once daily in the morning 2
• Week 2: 1 tablet twice daily (morning and evening) 2
• Week 3: 2 tablets in morning, 1 tablet in evening 2
• Week 4 onward: 2 tablets twice daily (maximum dose: 32 mg naltrexone/360 mg bupropion total daily) 2

Discontinuation criteria:

• Stop if <5% weight loss at 12 weeks 2

Expected weight loss: 5-6.1% total body weight loss at 56 weeks 2, 4

Option 3: Bupropion Monotherapy - If Combination Therapy Contraindicated

Bupropion alone produces modest weight loss of 2.77 kg at 6-12 months. 2, 5

Standard dosing for weight loss effect uses doses similar to those for depression or smoking cessation, though specific weight loss dosing is not FDA-approved for monotherapy. 5

Special Considerations for This Patient's History

Colostomy Considerations

Avoid orlistat entirely in patients with colostomy due to:

• Severe gastrointestinal side effects with steatorrhea 2
• Malabsorption of fat-soluble vitamins 2
• Potential complications with ostomy management

Hernia Considerations

• Phentermine/topiramate ER and bupropion/naltrexone SR have no specific contraindications related to hernia history 2
• Weight loss itself will reduce intra-abdominal pressure and hernia recurrence risk 2

Diverticulitis History

• No specific contraindications for either medication combination with resolved diverticulitis 2
• Weight loss improves overall gastrointestinal health 2

Contraindications to Screen For

Before prescribing phentermine/topiramate ER, exclude: 3, 6

• Uncontrolled hypertension
• Cardiovascular disease
• Hyperthyroidism
• Glaucoma
• History of drug abuse
• MAOI use within 14 days
• Pregnancy (teratogenic risk—requires negative pregnancy test and contraception) 6

Before prescribing bupropion/naltrexone SR, exclude: 2

• Uncontrolled hypertension
• Seizure history or conditions predisposing to seizures
• Eating disorders (bulimia/anorexia)
• Opioid dependence or current opioid use
• Abrupt discontinuation of alcohol or benzodiazepines

Monitoring Requirements

For phentermine/topiramate ER: 1

• Baseline and periodic: electrolytes, creatinine, blood pressure, heart rate
• Monitor for: cognitive impairment, mood changes, suicidal ideation, metabolic acidosis

For bupropion/naltrexone SR: 2

• Baseline and periodic: blood pressure, heart rate
• Monitor for: seizures, neuropsychiatric symptoms, hepatotoxicity

Essential Counseling Points

All pharmacotherapy must be combined with:

• Medical nutrition therapy with calorie restriction 2, 3
• Physical activity (≥150 minutes/week moderate-intensity exercise) 2
• Behavioral interventions including self-monitoring 2

Common pitfall to avoid: Never prescribe bupropion and topiramate as separate medications thinking you can replicate the FDA-approved combination—the interaction profile is dangerous and this approach is not evidence-based. 1