The psychopharmacology algorithm project at the Harvard South Shore Program: An algorithm for adults with obsessive-compulsive disorder.

A previous algorithm for the pharmacological treatment of obsessive-compulsive disorder was published in 2012. Developments over the past 7 years suggest an update is needed. The authors conducted searches in PubMed, focusing on new studies and reviews since 2012 that would support or change previous recommendations. We identified exceptions to the main algorithm, including pregnant women and women of child-bearing potential, the elderly, and patients with common medical and psychiatric co-morbidities. Selective serotonin reuptake inhibitors (SSRIs) are still first-line. An adequate trial requires a period at typical antidepressant doses and dose adjustments guided by a plasma level to evaluate for poor adherence or ultra-rapid metabolism. If the response is inadequate, consider a trial of another SSRI this time possibly taken to a very high dose. Clomipramine could be an alternative. If the response to the second trial remains inadequate, the next recommendation is to augment with aripiprazole or risperidone. Alternatively, augmentation with novel agents could be selected, including glutamatergic (memantine, riluzole, topiramate, n-acetylcysteine, lamotrigine), serotonergic (ondansetron), and anti-inflammatory (minocycline, celecoxib) agents. A third option could be transcranial magnetic stimulation. Lastly, after several of these trials, deep brain stimulation and cingulotomy have evidence for a role in the most treatment-refractory patients.