What medication options and dosing are recommended for an 18‑year‑old patient with anorexia nervosa?

Medication Options for Anorexia Nervosa in an 18-Year-Old

No medications are approved or recommended for the primary treatment of anorexia nervosa at any age, including 18-year-olds, and current evidence does not support routine pharmacologic treatment for weight restoration. 1

Primary Treatment Approach

Eating disorder-focused psychotherapy combined with nutritional rehabilitation and weight restoration is the cornerstone of anorexia nervosa treatment, not medication. 1

• At 18 years old, if a caregiver is present and involved, family-based treatment with caregiver involvement is the strongly recommended first-line approach 1, 2
• If no caregiver is available or the patient is living independently, eating disorder-focused individual psychotherapy targeting normalization of eating behaviors, weight restoration, and reduction of fear of weight gain should be initiated 1
• Individualized nutritional rehabilitation with weekly weight-gain goals must be implemented as a mandatory component of care 1, 2

Mandatory Pre-Treatment Safety Assessment

Before considering any psychotropic medication as an adjunct (even for comorbid conditions), the following assessments are required:

• Electrocardiogram (ECG) is mandatory because QTc prolongation is common in restrictive anorexia nervosa, and many psychiatric medications can further prolong the QTc interval 1
• Comprehensive metabolic panel including electrolytes 1
• Complete blood count 1
• Vital signs with orthostatic blood pressure measurement 1

When Medications May Be Considered

Medications should only be considered as adjuncts for comorbid psychiatric conditions (such as severe depression or anxiety), not for anorexia nervosa itself:

• If a medication with QT-prolonging potential is prescribed for a comorbid condition, repeat ECG monitoring is required 1
• Standard antidepressants may be used for comorbid depression or anxiety, but they do not treat the core anorexia nervosa pathology 1

Critical Pitfalls to Avoid

• Never initiate psychotropic medication without prior cardiac evaluation, as both anorexia nervosa and certain psychiatric drugs can prolong the QTc interval 1
• Do not use oral contraceptives to "treat" amenorrhea in anorexia nervosa, as they create false reassurance with withdrawal bleeding but do not restore spontaneous menses and may compromise bone health 1
• Do not delay or substitute psychotherapy and nutritional rehabilitation with medication trials 1

Multidisciplinary Team Requirement

All eating disorder treatment requires coordination among medical, psychiatric, psychological, and nutritional expertise throughout the entire treatment duration 1, 2, 3