What treatment options are available for a 16-year-old patient with bulimia nervosa who is currently taking Latuda (lurasidone) and Lamictal (lamotrigine)?

Treatment of Bulimia Nervosa in a 16-Year-Old on Latuda and Lamictal

For your 16-year-old patient with bulimia nervosa currently on Latuda and Lamictal, fluoxetine (Prozac) at high doses (60-80 mg daily) is the first-line pharmacological treatment, as it is the only FDA-approved medication for bulimia nervosa and has the strongest evidence base for reducing binge-purge episodes. 1, 2, 3, 4

Initial Assessment Requirements

Before initiating treatment, you must complete a comprehensive evaluation:

• Quantify eating behaviors: Document the specific frequency and intensity of binge eating episodes and purging behaviors (vomiting, laxative use, excessive exercise) 5
• Obtain vital signs: Check orthostatic pulse and blood pressure, resting heart rate, temperature, height, weight, and BMI percentile for age 5
• Physical examination: Look specifically for signs of purging including dental enamel erosion, parotid gland enlargement, Russell's sign (calluses on knuckles), and signs of dehydration 5, 6
• Laboratory assessment: Order complete blood count, comprehensive metabolic panel with electrolytes (particularly potassium), liver enzymes, and renal function tests 5
• ECG: This is essential given the patient is already on Latuda (which can prolong QTc) and purging behaviors can cause electrolyte abnormalities that further increase cardiac risk 5
• Screen for co-occurring conditions: Assess for depression, anxiety, obsessive-compulsive disorder, and suicidal ideation, which are common comorbidities 5

Pharmacotherapy Recommendations

First-Line: High-Dose Fluoxetine

Fluoxetine 60-80 mg daily is the evidence-based pharmacological treatment for bulimia nervosa in adolescents. 1, 3, 4

• This is significantly higher than typical antidepressant dosing and is necessary for efficacy in bulimia 3, 4
• Start at 20 mg daily and titrate up to 60-80 mg over 2-4 weeks based on tolerability 4
• Fluoxetine reduces binge-purge frequency and improves mood symptoms 2, 3
• It is generally well-tolerated with minimal drug interactions with Latuda and Lamictal 4

Alternative SSRI Options

If fluoxetine is not tolerated or contraindicated:

• Sertraline 100-200 mg daily has demonstrated efficacy in reducing binge-purge episodes in controlled trials 2, 3
• Other SSRIs (paroxetine, citalopram, escitalopram) may be effective but have less robust evidence 3, 4

Regarding Current Medications

Important consideration about Lamictal (lamotrigine): Interestingly, your patient is already on lamotrigine, which has emerging evidence for treating bulimia nervosa, particularly in patients with significant mood instability and poor impulse control 7. This medication may already be providing some benefit for the eating disorder symptoms, though it was likely prescribed for mood stabilization 7.

• Continue the Lamictal as it may be synergistic with SSRI treatment 7
• Monitor for any mood changes when adding fluoxetine, as SSRIs can occasionally trigger mood instability in susceptible individuals 7

Latuda (lurasidone): Continue this medication as prescribed for its primary indication; there are no significant contraindications to combining it with SSRIs for bulimia treatment 4

Non-Pharmacological Treatment (Essential Component)

Medication alone is insufficient; you must provide or refer for eating disorder-focused psychotherapy concurrently. 5, 1

• Cognitive-behavioral therapy (CBT) specifically adapted for bulimia nervosa is the gold-standard psychotherapy 1
• Interpersonal therapy (IPT) is an alternative evidence-based option 1
• Individual or group formats are both effective 1
• Family-based therapy should be strongly considered given the patient's age 5

Monitoring and Follow-Up

Establish a structured monitoring plan:

• Weekly visits initially to track binge-purge frequency, weight, and vital signs 5, 8
• Monthly electrolyte monitoring if purging continues, particularly potassium and bicarbonate 5, 6
• Repeat ECG at 1-2 months after starting fluoxetine, given the combination with Latuda 5
• Assess treatment response at 8-12 weeks: Expect at least 50% reduction in binge-purge frequency with effective treatment 2, 3

Critical Safety Considerations

Watch for these complications of bulimia nervosa:

• Hypokalemia and hypochloremic alkalosis from vomiting can cause cardiac arrhythmias 5, 6
• Dental complications from gastric acid exposure 6
• Gastrointestinal issues including esophagitis, gastric rupture (rare but life-threatening), and constipation 6
• Suicidal ideation, which is elevated in eating disorders 5

Treatment Goals and Expectations

The primary treatment goal is normalization of eating patterns and cessation of purging behaviors, not weight loss. 1, 8

• Set realistic expectations: Complete remission may take 6-12 months 3
• Emphasize that dieting and restrictive eating paradoxically worsen binge eating 5
• Address body image distortion and self-worth tied to weight/shape 5

When to Consider Hospitalization

Admit to inpatient or intensive day program if:

• Severe electrolyte abnormalities (K+ <3.0 mEq/L) 5
• Cardiac arrhythmias or significant QTc prolongation 5
• Suicidal ideation with plan or intent 5
• Failure of outpatient treatment with medical instability 5