Eating Disorders
Clinical Snapshot
Eating disorders are serious psychiatric illnesses defined by disturbed eating behaviour and a pathological relationship with body weight and shape — anorexia nervosa (restriction of intake leading to a significantly low body weight, with intense fear of weight gain and disturbance in how body weight or shape is experienced), bulimia nervosa (recurrent binge eating followed by compensatory behaviour such as self-induced vomiting, laxative misuse, or excessive exercise, typically at a normal or higher body weight), and binge eating disorder (recurrent binge eating without compensatory behaviour).[1] All three carry genuine medical risk — electrolyte disturbances, cardiac complications, and loss of bone density are common and can become life-threatening — alongside the psychiatric illness itself. Nutritional rehabilitation and eating-disorder-focused psychotherapy are the foundation of treatment for every eating disorder; medication has a limited, adjunctive role and is not an effective stand-alone treatment for any of the three. Effective care is genuinely multidisciplinary — medicine, psychiatry, psychology, and dietetics working together — and pharmacists are positioned to catch two of the highest-stakes, most preventable pharmacotherapy errors in this population: prescribing bupropion to a patient with any eating disorder history, and missing the electrolyte and refeeding-syndrome risks of nutritional rehabilitation.[2]
Recognize the Condition
General presentation clues
Consider an eating disorder in any patient with unexplained weight loss or marked weight fluctuation, amenorrhea or menstrual irregularity, GI complaints without another clear explanation, unexplained electrolyte abnormalities, dental erosion, or a family or patient report of unusual eating patterns, food rituals, or body-image preoccupation. Presentation spans the entire weight spectrum — a patient can have clinically significant bulimia nervosa or binge eating disorder at a completely normal or elevated body weight, so a normal weight must never be used on its own to rule an eating disorder out.
The three eating disorder categories covered in this chapter
Anorexia nervosa
Restriction of energy intake leading to a significantly low body weight, intense fear of gaining weight or persistent behaviour that interferes with weight gain, and disturbance in how body weight or shape is experienced. May occur with or without recurrent binge/purge episodes.
Bulimia nervosa
Recurrent binge eating (eating an objectively large amount of food with a sense of loss of control) followed by recurrent inappropriate compensatory behaviour — self-induced vomiting, laxative or diuretic misuse, fasting, or excessive exercise — occurring on average at least once a week for 3 months, with self-evaluation unduly influenced by body shape and weight. Typically presents at a normal or above-normal body weight.
Binge eating disorder
Recurrent binge eating, on average at least once a week for 3 months, with marked distress about the bingeing, but without the recurrent compensatory behaviour that defines bulimia nervosa.
Physical examination findings
- Bradycardia, orthostatic hypotension, or hypothermia from malnutrition or dehydration.
- Lanugo hair, hypercarotenemia, and dry skin with significant malnutrition.
- Parotid gland hypertrophy and dental erosion from recurrent vomiting.
- Russell sign — calluses or scarring over the knuckles from repeated self-induced vomiting.
- Peripheral edema, proximal myopathy, and neuromuscular hyperirritability (Chvostek and Trousseau signs) with advanced malnutrition or electrolyte disturbance.
Risk Factors
- Personal or family history of an eating disorder, depression, anxiety, or obsessive-compulsive disorder.
- A history of dieting, weight-based teasing, or participation in activities that emphasize leanness or a specific body shape (e.g., certain competitive sports, dance, modelling).
- Perfectionism and rigid, all-or-nothing thinking styles.
- A history of trauma, including sexual abuse.
- Family dysfunction or a high-conflict family environment.
- For binge eating disorder specifically: a family history of addiction, and comorbid attention-deficit/hyperactivity disorder.
- Sexual and gender minority identity is associated with elevated risk across all eating disorder types.
- Type 1 diabetes mellitus, particularly for insulin omission or restriction used as a compensatory behaviour.
Red Flags & Refer
Any of the following indicates a medical emergency or the need for urgent escalation beyond routine outpatient eating-disorder care:
- Severe bradycardia or other signs of cardiac compromise from malnutrition or purging — including new arrhythmia, syncope, or chest pain.
- Significant electrolyte derangement, particularly hypokalemia, hypophosphatemia, or hypomagnesemia.
- Signs of refeeding syndrome during nutritional rehabilitation — a rapid fall in phosphate, potassium, or magnesium, or new peripheral edema, in the first 1-2 weeks of increasing caloric intake.[3]
- Active suicidal ideation or self-harm.
- Medical instability requiring hospitalization — severe bradycardia, hypotension, hypothermia, hypoglycemia, or a very low or rapidly falling body weight.[4]
- Hematemesis or severe abdominal pain — consider an esophageal (Mallory-Weiss) tear or, rarely, gastric dilation associated with a binge episode.
- Loss of consciousness, seizure, or confusion — evaluate for hypoglycemia or severe electrolyte disturbance before attributing symptoms to the eating disorder alone.
Assessment & Diagnosis
Differentiating the three eating disorders
| Feature | Anorexia nervosa | Bulimia nervosa | Binge eating disorder |
|---|---|---|---|
| Typical body weight | Significantly low for age, sex, and developmental trajectory | Normal or above-normal | Often above-normal, but occurs across the full weight spectrum |
| Binge eating present | Only in the binge/purge subtype | Yes — required for diagnosis | Yes — required for diagnosis |
| Compensatory behaviour (vomiting, laxatives, fasting, excessive exercise) | May be present (binge/purge subtype) or absent (restricting subtype) | Yes — required for diagnosis | Absent — its absence is what distinguishes BED from bulimia nervosa |
| Core cognitive feature | Intense fear of weight gain; disturbance in how body weight or shape is experienced | Self-evaluation unduly influenced by body shape and weight | Marked distress specifically about the bingeing itself |
| Frequency threshold | Not frequency-based — defined by low weight and associated cognitions/behaviour | Binge eating and compensatory behaviour both on average at least once weekly for 3 months | Binge eating on average at least once weekly for 3 months |
Based on DSM-5-TR diagnostic criteria.[1] A patient can transition between these presentations over time (e.g., restricting-type anorexia nervosa developing binge/purge episodes) — reassess the working diagnosis at each visit rather than assuming it is fixed.
History
- Detailed eating history: current intake pattern, any binge episodes (size, frequency, sense of control), and any compensatory behaviour (vomiting, laxative/diuretic/enema misuse, fasting, excessive exercise, or insulin restriction in a patient with diabetes).
- Menstrual history, body image, and weight- or shape-related cognitions.
- Depression, anxiety, obsessive-compulsive symptoms, suicidal ideation, substance use, and family dysfunction or trauma history.
- Symptoms of malnutrition or electrolyte disturbance: chest pain, palpitations, syncope, hematemesis, seizures, abdominal pain, muscle weakness or cramping, and episodes of confusion.
- Autonomic symptoms that increase arrhythmia risk: episodic sweating, changes in heart rate or blood pressure with position, and sudden urgency to defecate or urinate.
Investigations
- Electrolytes, including magnesium and phosphate specifically (not always part of a routine basic metabolic panel) — critical both at baseline and, even more importantly, during nutritional rehabilitation.[5]
- Creatinine, glucose, CBC, and liver function tests.
- ECG — assess for bradycardia, arrhythmia, and QTc prolongation.
- Vital signs, including orthostatic blood pressure and heart rate.
- Pregnancy testing where clinically relevant — amenorrhea does not exclude the possibility of pregnancy.
What not to over-rely on: a single normal serum potassium does not exclude clinically important purging behaviour or cardiac risk — purging can cause intermittent, rapidly-corrected electrolyte shifts that one sample can miss. A normal body weight or BMI does not rule out bulimia nervosa or binge eating disorder and should never be the sole basis for deciding an eating disorder assessment is unnecessary. Routine bone density (DEXA) scanning is not indicated at the initial visit — reserve it for patients who meet the duration and risk criteria described in Monitoring and Follow-up.
Treatment Targets
- Achieve and maintain medical stability — normalize vital signs, correct electrolyte disturbances, and resolve any acute medical risk.
- Restore body weight to a healthy, individualized target range in anorexia nervosa, and prevent further weight loss where restoration is not yet the immediate goal.
- Eliminate binge eating and, in bulimia nervosa, eliminate compensatory (purging) behaviour.
- Normalize eating patterns and reduce food-related rituals and avoidance.
- Treat coexisting psychiatric conditions — depression, anxiety, obsessive-compulsive symptoms, suicidality.
- Restore normal cognitive and emotional function — this generally requires nutritional rehabilitation first, since malnutrition itself impairs cognition and makes psychotherapy less effective.
- Restore menstrual function and protect bone health.
- Prevent relapse and support long-term recovery through continued multidisciplinary follow-up.
Choose Initial Treatment
Every eating disorder, 1st line nutritional rehabilitation (where applicable) plus eating-disorder-focused psychotherapy — medication is never a substitute for these and is rarely sufficient as a stand-alone treatment for any eating disorder.[1]
Anorexia nervosa
1st line structured nutritional rehabilitation with a dietitian, set at a realistic weight-gain rate for the treatment setting, combined with eating-disorder-focused psychotherapy — family-based treatment (FBT) for children and adolescents, and cognitive behavioural therapy for eating disorders (CBT-ED) or specialist supportive clinical management for adults.[6]
Special situation — when anxiety, obsessional rumination, or rigid cognitions about food and weight are significantly limiting engagement with nutritional rehabilitation despite an adequate trial of the above, add olanzapine — start 0.625-1.25 mg PO daily and titrate slowly to a usual dose of 2.5-5 mg PO daily, typically for a defined 3-4 month course. Olanzapine has the most consistent evidence among medications tried in anorexia nervosa, though overall evidence remains limited and not every trial has shown benefit — it is an adjunct used selectively, never a routine or stand-alone treatment.[2]
Begin nutritional rehabilitation cautiously in any patient with minimal recent intake — assess refeeding syndrome risk before the first meal, start thiamine before or at the same time as feeding begins, and monitor phosphate, potassium, and magnesium daily for at least the first several days of refeeding in a higher-risk patient.[3]
Bulimia nervosa
1st line cognitive behavioural therapy for bulimia nervosa (CBT-BN) — guided self-help CBT is a reasonable, accessible starting point for adolescents and adults without a significant psychiatric comorbidity.
Add fluoxetine when psychotherapy alone is insufficient, inaccessible, or the patient prefers combined treatment — fluoxetine is the only medication with a formal indication for bulimia nervosa, dosed at 60 mg PO daily, substantially higher than typical antidepressant dosing, since this dose showed the greatest reduction in binge/purge frequency in trials.[2]
Avoid bupropion is contraindicated in any patient with a current or past diagnosis of bulimia nervosa or anorexia nervosa — it carries a materially increased seizure risk in this population, an association strong enough that Health Canada-approved labelling lists any eating disorder history as a contraindication.[7] Do not select bupropion for a patient with any eating disorder history, even when depression is the presenting complaint and bupropion would otherwise be a reasonable choice.
Binge eating disorder
1st line cognitive behavioural therapy (individual, group, or guided self-help) — effective at reducing binge frequency independent of medication.
Add lisdexamfetamine for moderate-to-severe binge eating disorder, particularly when psychotherapy alone is insufficient or not accessible — it is the only medication with a Health Canada-approved indication for binge eating disorder in adults. Start 30 mg PO once daily, titrate by 20 mg increments at intervals of at least 1 week as needed, to a target of 50-70 mg daily (maximum 70 mg daily).[8]
Alternative — use topiramate off-label when lisdexamfetamine is contraindicated, not tolerated, or otherwise inappropriate (e.g., significant cardiovascular disease or a history of stimulant misuse). Start 25 mg PO at bedtime and titrate by 25 mg increments no more often than weekly to an effective range of 100-200 mg daily, to a maximum of 400 mg daily if needed and tolerated. Expect a meaningfully higher discontinuation rate from adverse effects (cognitive slowing, paresthesia) than with lisdexamfetamine.[9]
Non-Pharmacologic Treatment
Nutritional rehabilitation (anorexia nervosa)
Structured nutritional rehabilitation, guided by an experienced dietitian, is foundational to anorexia nervosa treatment — psychological and cognitive function will not normalize until nutritional status improves. Set stepwise, individualized weight-gain targets appropriate to the treatment setting: roughly 0.9-1.8 kg per week for hospitalized or residential patients, 0.4-1.4 kg per week for partial hospitalization, and 0.4-0.9 kg per week for outpatient programs, continuing until a healthy weight and normalized growth trajectory are achieved.[10] Oral nutritional supplements can be used when food alone cannot achieve the target rate of gain; tube feeding may be needed if oral intake fails despite structured support. Trained meal support — family members or staff present and actively engaged at mealtimes — improves adherence.
Psychotherapy
- Family-based treatment (FBT) is the best-supported approach for children and adolescents with anorexia nervosa — it trains parents to take an active role in renourishing their child and progresses through phases of parental control, gradually returning control of eating to the adolescent as recovery progresses.[6]
- Cognitive behavioural therapy for eating disorders (CBT-ED) and specialist supportive clinical management are appropriate first-line psychotherapies for adults with anorexia nervosa.
- CBT for bulimia nervosa (CBT-BN) directly targets the binge-purge cycle and the overvaluation of shape and weight that drives it; guided self-help CBT is an accessible, effective early option for adolescents and adults with bulimia nervosa or binge eating disorder who do not have significant psychiatric comorbidity.
- CBT is the standard first-line psychotherapy for binge eating disorder; other modalities, such as dialectical behaviour therapy, are reasonable alternatives depending on therapist availability and patient fit.
- Family therapy and the involvement of all family members materially improves outcomes for children and adolescents across every eating disorder type, not anorexia nervosa alone.
General supportive measures
- Limit or supervise exercise in any medically unstable or significantly underweight patient — unrestricted exercise can worsen medical risk and interfere with weight restoration.
- Address binge/purge and laxative-misuse behaviour with explicit, gradual tapering goals rather than expecting abrupt cessation, particularly for chronic laxative misuse.
- Screen for and treat comorbid depression, anxiety, obsessive-compulsive symptoms, substance use, and suicidality — recovery from the eating disorder is unlikely without addressing these.
- Build and maintain a genuine therapeutic alliance — engagement and rapport materially affect whether a patient stays in treatment, given how often ambivalence toward treatment is itself part of the illness.
Special Populations
Pregnancy
Amenorrhea does not reliably prevent pregnancy in anorexia nervosa — ovulation can occur even while a patient remains amenorrheic, so effective contraception counselling is still needed for any sexually active patient who does not wish to conceive.[10] If pregnancy occurs, follow it as a high-risk pregnancy unless the eating disorder is genuinely mild, involve a dietitian for nutrition and supplement recommendations, and reassess every medication for pregnancy risk rather than assuming continuation is safe — use an individualized risk-benefit approach and favour non-pharmacologic measures where possible. Eating disorder symptoms can improve or worsen during pregnancy in different patients, so ongoing reassessment through pregnancy and the postpartum period, including for anxiety, depression, and suicidality, is required regardless of the pre-pregnancy course.
Breastfeeding
Most patients with an eating disorder, including anorexia nervosa, can successfully breastfeed; severe, unremitted anorexia nervosa can reduce milk supply. Refer to a dietitian to optimize both maternal and infant nutrition during lactation.
Children and adolescents
Family-based treatment is the best-supported first-line psychotherapy for adolescent anorexia nervosa and involves the whole family, not just the patient.[6] Weight targets in growing children and adolescents should be set against an appropriate growth-chart trajectory rather than a fixed adult BMI threshold. Medication evidence in this age group is more limited than in adults — reserve pharmacotherapy for the same specific situations as in adults (e.g., persistent anxiety or rigid cognitions limiting nutritional rehabilitation in anorexia nervosa) and involve a clinician experienced in pediatric psychopharmacology.
Renal and hepatic considerations
Adjust electrolyte and phosphate repletion doses to renal function, and monitor renal function closely when repleting phosphate or potassium in a patient with reduced renal clearance. Topiramate increases nephrolithiasis risk — ensure adequate hydration and use caution with a personal history of kidney stones or significant renal impairment. Monitor liver function periodically with olanzapine.
Older adults
Eating disorders are underrecognized in older adults but do occur, including late-onset and long-standing chronic presentations; the same medical risks apply and are often compounded by reduced physiologic reserve, so the threshold for medical escalation should be lower in this group.
Monitoring & Follow-Up
Medical monitoring
- Vital signs, including orthostatic blood pressure and heart rate, at every visit during active treatment, more frequently in a higher-risk or recently-hospitalized patient.
- Weight, tracked against the individualized target trajectory (not just a single target number) in anorexia nervosa.
- Electrolytes — potassium, phosphate, and magnesium specifically — checked daily for at least the first several days of nutritional rehabilitation in a higher-risk patient, then at a reduced frequency once stable.[3]
- ECG for any patient with significant bradycardia, electrolyte disturbance, or other cardiac risk features.
- Bone density (DEXA) after roughly 1 year of sustained low weight in children and adolescents, or 2 years in adults — repeat no more often than yearly unless new bone pain or a fracture occurs.[11]
- Return of menstrual function as a marker of physiologic recovery in anorexia nervosa.
Medication-specific monitoring
- Olanzapine: weight, fasting glucose/lipids, and extrapyramidal symptoms; reassess at the planned 3-4 month mark whether continued therapy is still needed.
- Fluoxetine (bulimia nervosa dose): response (binge/purge frequency), mood and suicidality (particularly early in treatment and in younger patients), and GI bleeding risk if combined with an NSAID or antiplatelet agent.
- Lisdexamfetamine: heart rate, blood pressure, appetite/weight trend, sleep, and mood; monitor growth in adolescents; screen for misuse given its stimulant/controlled-substance status.
- Topiramate: cognitive or word-finding complaints, mood, weight, and adequate hydration/renal stone symptoms.
Psychological monitoring
Track binge/purge frequency, body-image cognitions, mood, anxiety, and suicidality at every visit — improvement in weight or medical parameters alone does not confirm psychological recovery, and relapse risk remains significant even after apparent improvement.
Common Errors to Avoid
- Prescribing bupropion to a patient with any current or past eating disorder diagnosis — this carries a materially increased seizure risk and is never appropriate in this population, regardless of the indication being treated.
- Treating any eating disorder with medication alone, without nutritional rehabilitation and psychotherapy — medication is an adjunct, not a substitute.
- Dosing fluoxetine for bulimia nervosa the same way as for depression — the bulimia nervosa dose (60 mg/day) is substantially higher than typical antidepressant dosing.
- Missing refeeding syndrome risk when reintroducing nutrition too quickly in a patient with minimal recent intake — check phosphate, potassium, and magnesium specifically (not just a routine electrolyte panel) and give thiamine before or at the start of feeding.
- Assuming a normal or above-normal body weight excludes bulimia nervosa or binge eating disorder — both occur across the full weight spectrum.
- Failing to ask directly and specifically about purging, laxative or diuretic misuse, and compensatory exercise — patients rarely volunteer this information unprompted.
- Relying on a single normal potassium or ECG to exclude ongoing cardiac risk in a patient who purges intermittently.
- Starting lisdexamfetamine or topiramate for binge eating disorder without also arranging psychotherapy — medication alone is not the standard of care.
- Overlooking bone health — not arranging DEXA screening when duration/severity criteria are met, or assuming bone loss will fully reverse once weight is restored.
- Attributing GI, cardiac, or neurologic symptoms in a patient with a known eating disorder to anxiety without an appropriate medical work-up.
Clinical Decision Algorithm
Drug Tables
How to use this table: Doses are adult doses and require patient-specific confirmation, including renal/hepatic adjustment and, in children and adolescents, weight-based dosing under specialist direction. Select any drug name to open its complete Pharmasist Drug Database page.
Second-generation antipsychotics — anorexia nervosa
Adjunctive only, used selectively during nutritional rehabilitation — never a routine or stand-alone treatment.
| Drug | Dosage | Adverse effects | Drug interactions | Comments |
|---|---|---|---|---|
| Olanzapine | Start 0.625-1.25 mg PO daily; titrate slowly to a usual maintenance dose of 2.5-5 mg PO daily. Time-limited course of approximately 3-4 months, or until no longer needed for weight gain/cognitive symptoms. | Sedation, extrapyramidal symptoms/akathisia, dyslipidemia; rare drug reaction with eosinophilia and systemic symptoms (DRESS). | Fluvoxamine and other CYP1A2 inhibitors can increase olanzapine levels; CYP1A2 inducers (e.g., carbamazepine, cigarette smoking) can reduce levels — a dose reduction may be needed after smoking cessation. Avoid combining with other agents that carry extrapyramidal symptom risk. | Best-evidenced medication tried in anorexia nervosa for reducing rigid or obsessional food- and weight-related cognitions and supporting weight gain, though evidence is mixed across trials and the effect size is modest. Monitor weight, fasting glucose/lipids, and for movement disorder. |
Antidepressants
Fluoxetine is the only medication with a formal indication for an eating disorder in this class (bulimia nervosa); the others are reasonable alternatives when fluoxetine is not tolerated or not effective.
| Drug | Dosage | Adverse effects | Drug interactions | Comments |
|---|---|---|---|---|
| Fluoxetine, bulimia nervosa dose | 60 mg PO daily — substantially higher than typical antidepressant dosing; this higher dose is what showed the greatest reduction in binge/purge frequency in trials. | GI upset, anxiety, sexual dysfunction, increased GI bleeding risk. | Do not combine with an MAOI. Inhibits CYP2D6, which can increase levels/toxicity of many co-administered drugs (e.g., atomoxetine, dextromethorphan, mirtazapine, risperidone, tricyclic antidepressants). Increased GI bleeding risk with NSAIDs or antiplatelet agents. | Continue at least 6 months, preferably 6-12 months once effective, before considering a taper. No proven benefit to combining with a second antidepressant. |
| Fluoxetine, binge eating disorder dose | 20-60 mg PO daily. | Same as above. | Same as above. | A reasonable alternative to lisdexamfetamine or topiramate, particularly with comorbid depression or anxiety; SSRIs as a class have not been shown to produce weight loss in binge eating disorder. |
| Venlafaxine | 75-150 mg PO daily. | Nausea, dizziness, dry mouth; hypertension at higher doses. | CYP2D6/CYP3A4 inhibitors (e.g., erythromycin, clarithromycin, ketoconazole) can increase levels; do not combine with an MAOI; caution combining with trazodone (serotonin syndrome risk). | An alternative when fluoxetine is not effective or not tolerated; no proven advantage of one antidepressant over another for bulimia nervosa. |
| Trazodone | 100-500 mg PO daily, single or divided doses. | Sedation (common); anticholinergic effects less prominent than with tricyclics. | Do not combine with an MAOI; caution with other serotonergic drugs; CYP3A4 inhibitors can increase levels. | Particularly useful when insomnia accompanies bulimia nervosa. |
Amphetamine-based agent — binge eating disorder
The only medication with a Health Canada-approved indication specifically for binge eating disorder.
| Drug | Dosage | Adverse effects | Drug interactions | Comments |
|---|---|---|---|---|
| Lisdexamfetamine | Start 30 mg PO once daily in the morning; titrate by 20 mg increments at intervals of at least 1 week as needed, to a target of 50-70 mg daily (maximum 70 mg/day). | Decreased appetite, insomnia, dry mouth, irritability, increased heart rate and blood pressure, headache; rare psychotic symptoms at higher doses. | Do not combine with an MAOI (hypertensive crisis risk). Caution with other serotonergic drugs. Weak CYP2D6 inhibitor. | Confirm cardiovascular status before starting. Controlled substance — screen for misuse potential and monitor growth in adolescents. |
Anticonvulsant — binge eating disorder (off-label)
A reasonable off-label alternative when lisdexamfetamine is contraindicated, not tolerated, or inappropriate; evidence supports efficacy, but adverse effects limit its use as a routine first choice.
| Drug | Dosage | Adverse effects | Drug interactions | Comments |
|---|---|---|---|---|
| Topiramate | Start 25 mg PO at bedtime; titrate by 25 mg increments no more often than weekly, as tolerated, to an effective range of 100-200 mg/day (maximum 400 mg/day in divided doses). | Cognitive slowing/word-finding difficulty, paresthesia, somnolence, weight loss, nephrolithiasis risk, rare metabolic acidosis. | Additive CNS depression with alcohol or other CNS depressants; may reduce hormonal contraceptive efficacy at higher doses. | Higher discontinuation rate from adverse effects than lisdexamfetamine — reserve for when the preferred agent is not an option. |
Refeeding syndrome and nutritional rehabilitation
Applies across all eating disorder types whenever a patient with minimal recent intake begins nutritional rehabilitation — hypophosphatemia is the hallmark of refeeding syndrome, and its correction alongside cautious caloric advancement is the core of prevention.
| Drug | Dosage | Adverse effects | Drug interactions | Comments |
|---|---|---|---|---|
| Thiamine | 100 mg PO or IM daily, started before or at the same time as feeding begins, continued through at least the first several days of nutritional rehabilitation. | None expected at this dose. | None significant. | Prevents Wernicke-Korsakoff syndrome — give proactively; do not wait for neurologic symptoms to appear. |
| Phosphate repletion (potassium phosphate) | Oral tablet or powder repletion for mild-to-moderate hypophosphatemia, dosed per product and severity; severe or symptomatic hypophosphatemia requires intravenous phosphate repletion under institutional protocol. | GI upset; hyperkalemia (this formulation contains potassium) or hypocalcemia with aggressive repletion. | Caution with concurrent potassium-sparing diuretics or ACE inhibitors/ARBs given the potassium component; adjust for renal function. | Anticipate and pre-empt — phosphate often falls before it becomes symptomatic in the first days of refeeding, which is why scheduled monitoring rather than symptom-triggered testing is required. |
| Potassium chloride | Oral or intravenous repletion under institutional protocol, per severity of hypokalemia. | GI upset with oral formulations; arrhythmia risk with rapid IV administration. | Additive hyperkalemia risk with potassium-sparing diuretics or ACE inhibitors/ARBs. | Purging-related potassium loss can recur quickly — recheck after repletion rather than assuming a single correction is durable. |
| Magnesium sulfate | Oral repletion under institutional protocol, per severity of hypomagnesemia. | Diarrhea (dose-limiting with oral repletion). | Caution in renal impairment — reduced clearance increases toxicity risk. | Magnesium depletion often accompanies phosphate and potassium depletion in refeeding syndrome and should be checked and corrected alongside them, not in isolation. |
References
- The American Psychiatric Association Practice Guideline for the Treatment of Patients With Eating Disorders — American Journal of Psychiatry, American Psychiatric Association (Crone C, Fochtmann LJ, Attia E, et al.). Am J Psychiatry 2023;180(2):167-171
- World Federation of Societies of Biological Psychiatry (WFSBP) guidelines update 2023 on the pharmacological treatment of eating disorders — World Journal of Biological Psychiatry, World Federation of Societies of Biological Psychiatry (Himmerich H, Lewis YD, Conti C, et al.). World J Biol Psychiatry 2023;24(8):643-706
- ASPEN Consensus Recommendations for Refeeding Syndrome — Nutrition in Clinical Practice, American Society for Parenteral and Enteral Nutrition (da Silva JSV, Seres DS, Sabino K, et al.). Nutr Clin Pract 2020;35(2):178-195
- Medical emergencies in eating disorders (MEED): guidance on recognition and management — Royal College of Psychiatrists, College Report CR233. RCPsych College Report CR233, May 2022
- Adverse outcomes and mortality in individuals with eating disorder-related electrolyte abnormalities in Ontario, Canada: a population-based cohort study — Lancet Psychiatry (Solmi M, Fabiano N, Clarke AE, et al.). Lancet Psychiatry 2024;11(10):818-827
- Canadian practice guidelines for the treatment of children and adolescents with eating disorders — Journal of Eating Disorders (Couturier J, Isserlin L, Norris M, et al.). J Eat Disord 2020;8:4
- Bupropion product monograph — contraindications in eating disorders — Health Canada. Health Canada Product Monograph
- Binge-eating disorder in adults: a systematic review and meta-analysis — Annals of Internal Medicine (Brownley KA, Berkman ND, Peat CM, et al.). Ann Intern Med 2016;165(6):409-420
- Efficacy and safety of topiramate in binge eating disorder: a systematic review and meta-analysis — CNS Spectrums (Nourredine M, Jurek L, Auffret M, et al.). CNS Spectr 2021;26(5):459-467
- Medical Management of Restrictive Eating Disorders in Adolescents and Young Adults — Journal of Adolescent Health, Society for Adolescent Health and Medicine (Golden NH, Katzman DK, Rome ES, et al.). J Adolesc Health 2022;71(5):648-654
- Eating disorders: recognition and treatment — National Institute for Health and Care Excellence. NICE guideline NG69, 2017 (updated 2020)
Professional reference only. Apply clinical judgment and verify patient-specific decisions against current authoritative guidance and product information.