What is the most appropriate first‑line pharmacologic treatment for anxiety in an adult patient with a comorbid eating disorder?

Best Anxiety Medication for Individuals with Disordered Eating

For adults with anxiety and comorbid eating disorders, selective serotonin reuptake inhibitors (SSRIs) are the recommended first-line pharmacologic treatment, with specific dosing and selection guided by the type of eating disorder present. 1, 2

Treatment Algorithm Based on Eating Disorder Type

For Bulimia Nervosa with Anxiety

• Fluoxetine 60 mg daily is the definitive first choice, as it is the only FDA-approved medication for bulimia nervosa and addresses both the eating disorder and anxiety symptoms simultaneously. 2, 3, 4
• This higher dose (60 mg, not the standard 20 mg antidepressant dose) is critical—standard antidepressant dosing is inadequate for bulimia nervosa and represents a common prescribing error. 2
• Fluoxetine should be initiated alongside cognitive-behavioral therapy (CBT) or if there is minimal response to psychotherapy alone by 6 weeks. 2

If fluoxetine is not tolerated:

• Switch to sertraline 100 mg daily or citalopram (particularly if prominent depressive symptoms coexist with anxiety). 2
• Continue eating disorder-focused CBT concurrently with alternative SSRI treatment. 2

For Anorexia Nervosa with Anxiety

• No medications are FDA-approved or recommended for primary treatment of anorexia nervosa—psychotherapy with nutritional rehabilitation remains the cornerstone. 2, 5
• If adjunctive pharmacotherapy is considered for severe anxiety interfering with treatment engagement, olanzapine 5 mg once daily has the strongest evidence for weight restoration benefits in anorexia nervosa. 2, 5
• SSRIs (fluoxetine, sertraline, escitalopram) may be used for comorbid anxiety symptoms, but only after cardiac safety evaluation. 1

For Binge Eating Disorder with Anxiety

• Lisdexamfetamine 50-70 mg daily is the only FDA-approved medication for binge eating disorder and may help with anxiety related to loss of control over eating. 6, 7
• SSRIs (particularly sertraline) are an alternative option when anxiety is the predominant concern or when stimulant medications are contraindicated. 7, 8
• Psychotherapy (eating disorder-focused CBT or interpersonal therapy) should be offered as first-line treatment, with medication reserved for those who prefer pharmacotherapy or have not responded to psychotherapy alone. 6, 7

Critical Pre-Treatment Safety Assessments

Before initiating any psychotropic medication in eating disorder patients, mandatory evaluations include: 2

• Electrocardiogram (ECG) to assess for QTc prolongation, which is common in restrictive eating disorders and can be exacerbated by SSRIs
• Comprehensive metabolic panel including electrolytes (especially in patients with purging behaviors)
• Orthostatic vital signs to detect autonomic instability
• Complete blood count for baseline hematologic status

SSRI Selection for Generalized Anxiety in Eating Disorders

When treating anxiety disorders (not social anxiety specifically) in patients with eating disorders:

• Fluoxetine, paroxetine, or escitalopram are recommended SSRIs with established safety profiles. 1
• Venlafaxine (SNRI) is suggested as an alternative when SSRIs are insufficient. 1
• Avoid mirtazapine and tricyclic antidepressants in patients with comorbid obesity and binge eating disorder, as these promote weight gain. 6

Monitoring Requirements

• Assess treatment response every 6-12 weeks by quantifying frequency of binge eating, purging episodes, and anxiety symptoms. 2
• Repeat ECG monitoring if prescribing medications with QT-prolonging potential (many SSRIs and antipsychotics). 2
• Monthly assessment for first 3 months, then at least every 3 months for medications used in binge eating disorder. 6

Common Pitfalls to Avoid

• Never use standard 20 mg fluoxetine dosing for bulimia nervosa—the evidence supports only 60 mg daily. 2
• Do not initiate psychotropic medication without prior cardiac evaluation in eating disorder patients, as both the illness and medications can prolong QTc. 2
• Avoid appetite-stimulating agents approved for cancer-related anorexia (megestrol acetate, dexamethasone) in anorexia nervosa—the pathophysiology and treatment goals differ fundamentally. 2
• Do not prescribe oral contraceptives to "treat" amenorrhea in anorexia nervosa, as this creates false reassurance without restoring spontaneous menses and may compromise bone health. 2

Multidisciplinary Coordination

All eating disorder treatment with pharmacotherapy requires coordination among medical, psychiatric, psychological, and nutritional expertise—including a primary care physician, mental health practitioner, and registered dietitian. 2, 7