Phenelzine drug withdrawal

Bipolar depression affects 1% of the general population, and treatment resistance is a significant problem. The addition of pindolol can lead to significant improvement in depressed patients who are resistant to antidepressant drugs, such as selective serotonin reuptake inhibitors or phenelzine. Of 17 patients with refractory bipolar depression, in whom pindolol was added to augment the effect of antidepressant drugs, eight responded favorably (95). However, two developed transient hypo-mania, and one of these became psychotic after the resolution of hypomanic symptoms. In both cases transient hypomanic symptoms resolved without any other intervention, while psychosis required pindolol withdrawal. 

That depends on the drug. Effects of drugs that reversibly bind to MAO (e.g., tranylcypromine) immediately cease upon withdrawal. Effects of drugs that bind irreversibly (e.g.. phenelzine) continue until new enzyme is formed, which may take as long as several weeks. 

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