07 - Bulimia nervosa (BN) and binge eating disorde

Bulimia nervosa (BN) and binge eating disorder (BED)

794 The Maudsley® Prescribing Guidelines in Psychiatry CHAPTER 9 and result in re-­feeding-­precipitated hypophosphataemia. Oral supplementation is used to prevent serious sequelae rather than to restore normal levels. If supplements are used, urea and electrolytes (U&Es), bicarbonate, calcium, phosphorus and magnesium need to be monitored and an ECG needs to be performed.30 Osteoporosis Bone loss is an important complication of AN with serious consequences. There is limited and conflicting evidence regarding the use of oestrogen, dehydroepiandrosterone (DHEA), combined oral contraceptives and bisphosphonates to improve bone density in AN. For those who have long-­term low body weight and low bone mineral density, 17β-estradiol (with cyclic progesterone) or oestrogen (in young women aged ­13–­17 years) and bisphosphonates (for women over 18 years) can be used. Antipsychotics that raise prolactin levels can further increase the risk of bone loss and osteoporosis6 and should be avoided. Relapse prevention A 2018 review suggested that fluoxetine, citalopram, sertraline or mirtazapine may have a role to play in relapse prevention and improving symptoms in weight-­restored patients.31 Evidence for this is very weak and since this review an RCT of fluoxetine has been published showing no effect.32 SSRIs can sometimes elevate prolactin so monitoring is recommended. Comorbid disorders Second-generation antidepressants are often used to treat comorbid major depression, anxiety and OCD. However, caution is necessary because depressive symptoms that are a consequence of self-­starvation are only likely to improve with weight restoration. As weight loss is a frequent side effect of bupropion, this antidepressant is contraindicated for the treatment of comorbid depression in AN.33 Mania and psychosis occurring in the context of AN is probably best treated with olanzapine, and bipolar depression with olanzapine plus fluoxetine.33 Bulimia nervosa (BN) and binge eating disorder (BED) Medicines should not be offered as the sole treatment for BN or BED.6 Fluoxetine is the only SSRI to hold a product licence for BN, and adults with BN and BED may be offered a trial of fluoxetine. The effective dose of fluoxetine is 60mg daily.34 Patients should be informed that fluoxetine can reduce the frequency of binge eating and purging but long-­term effects are unknown.35 Early response (at 3 weeks) is a strong predictor of response overall.36 Sertraline has also shown a reduction in binge eating and purging in both BN and BED, whereas citalopram showed improvement only in BED.15 Antidepressants may sometimes be used for the treatment of BN in adolescents, but they are not licensed for this age group and there is little evidence for this practice. They should not be considered as a first-­line treatment in adolescent BN.6 There is some reasonable evidence that topiramate15 reduces the frequency of binge eating although topiramate is contraindicated in pregnancy and in women of child-­ bearing potential (if not using a highly effective method of contraception). There is  rather limited evidence for the usefulness of aripiprazole, bupropion, duloxetine,