What is the initial treatment approach for a patient presenting with bulimia nervosa, characterized by binge and purging eating disorder?

Initial Treatment for Binge and Purging Eating Disorder (Bulimia Nervosa)

For adults with bulimia nervosa, begin eating disorder-focused cognitive-behavioral therapy (CBT) immediately and prescribe fluoxetine 60 mg daily either at treatment initiation or if there is minimal response to psychotherapy alone by 6 weeks. 1

Initial Assessment Requirements

Before initiating treatment, complete a thorough medical and psychiatric evaluation to identify life-threatening complications and guide treatment intensity:

Vital Signs and Physical Examination

• Measure temperature, resting heart rate, blood pressure, orthostatic pulse, and orthostatic blood pressure to detect cardiovascular instability 1
• Document height, weight, and BMI 1
• Examine for physical signs of purging: Russell's sign (calluses on knuckles), parotid gland enlargement, and dental erosion 1

Laboratory Assessment

• Order complete blood count to detect anemia and leukopenia 1
• Obtain comprehensive metabolic panel including electrolytes (sodium, potassium, chloride, bicarbonate), liver enzymes, and renal function tests to identify hypokalemia, hypochloremia, metabolic alkalosis, and organ dysfunction 1
• Perform electrocardiogram in all patients with severe purging behavior to assess for QTc prolongation, which increases risk of sudden cardiac death 1, 2

Psychiatric Evaluation

• Quantify eating and weight control behaviors: frequency and intensity of binge eating, purging (vomiting, laxatives, diuretics), dietary restriction, and excessive exercise 1
• Identify co-occurring psychiatric disorders, particularly depression and anxiety 1
• Assess suicide risk, as eating disorders have among the highest mortality rates of psychiatric illnesses 2

Treatment Algorithm for Adults

First-Line Treatment

• Initiate eating disorder-focused cognitive-behavioral therapy (CBT-BN) as the cornerstone of treatment, focusing on normalizing eating patterns, eliminating binge-purge cycles, and addressing distorted cognitions about weight and shape 1
• Prescribe fluoxetine 60 mg daily either at treatment initiation or if minimal response to psychotherapy occurs by 6 weeks 1
  • This is the only FDA-approved dose for bulimia nervosa; lower doses are ineffective 3
  • The 60 mg dose may be titrated up over several days for tolerability 3
  • Maximum therapeutic effect may require 5 weeks or longer 3

Rationale for Combined Treatment

The American Psychiatric Association guidelines explicitly recommend both CBT and fluoxetine because controlled trials demonstrate that 60 mg fluoxetine is statistically superior to placebo in reducing binge-eating and vomiting frequency 3. CBT addresses the psychological maintenance factors while fluoxetine provides additional symptom reduction 4, 5.

Alternative Psychotherapy Options

• Interpersonal psychotherapy (IPT) is effective, particularly for long-term outcomes, if CBT is unavailable or not tolerated 4
• Guided self-help programs using structured CBT manuals show promise as a first-step intervention 4, 6

Treatment Algorithm for Adolescents and Emerging Adults

For adolescents and emerging adults with an involved caregiver, initiate eating disorder-focused family-based treatment (FBT) as first-line therapy. 1, 7

• FBT achieves 48.6% remission at 6-12 months compared to 34.3% with individual treatment 7
• Parents take active control of refeeding and supervising eating behaviors initially 7
• Treatment involves all relevant family members and addresses psychosocial needs 7

Multidisciplinary Team Structure

All patients require a coordinated treatment plan incorporating medical, psychiatric, psychological, and nutritional expertise. 1, 2

• Physician: Monitors medical complications, manages medications, coordinates care 6
• Therapist: Delivers eating disorder-focused psychotherapy 6
• Registered dietitian: Provides nutritional counseling and meal planning 6
• Psychiatrist: Consultation beneficial for complex cases or medication management 6

Monitoring During Treatment

Cardiac Monitoring

• Continue monitoring QTc intervals in patients with severe purging due to ongoing risk of sudden cardiac death from electrolyte abnormalities 2
• Most cardiac manifestations reverse completely with nutritional rehabilitation 2

Treatment Response Assessment

• Assess response to psychotherapy by 6 weeks; if minimal improvement, add or optimize fluoxetine 1
• Monitor for treatment dropout, as over 50% of patients fail to achieve abstinence from binge-purge behaviors with CBT alone 8

Critical Pitfalls to Avoid

• Do not prescribe fluoxetine at doses below 60 mg/day for bulimia nervosa, as only this dose demonstrated efficacy in controlled trials 3
• Do not delay hospitalization if severe medical complications are present: marked bradycardia, hypotension, severe electrolyte disturbances, or suicidality require immediate medical stabilization 2
• Do not assume normal laboratory values exclude serious illness: approximately 60% of eating disorder patients show normal routine testing despite severe complications 2
• Do not minimize family involvement in adolescent treatment, as family-based approaches significantly outperform individual therapy in this age group 7

Maintenance and Continuation

• Continue fluoxetine for up to 52 weeks in patients who respond during acute treatment, as maintenance therapy demonstrates sustained benefit 3
• Periodically reassess need for continued treatment and adjust dosage to maintain patients on the lowest effective dose 3
• Bulimia nervosa is a chronic condition; continuation of treatment is reasonable for responding patients 1