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WHAT IS THE APPROPRIATE ANTIDEPRESSANT?Table 3Monoamine Oxidase InhibitorsMedications Initial/Max Dose Comments Adverse EffectsIsocarboxazid (Marplan) 10 mg bid/60 mg dailyDietary restrictions: no HTN crisis: palpitations,foods containing tyramine chest pain, muscle rigidity;Phenelzine (Nardil) 15 mg tid/90 mg daily(e.g., beer, wine, aged 5HT syndrome: nausea,Selegiline (Emsam) a 6 mg/12 mg (24-h transdermal patch)cheese, soy sauce, sedation, diaphoresis,bananas, smoked meat) confusion, HTNTranylcypromine (Parnate) 30 mg/60 mg (divided doses)aSelective monoamine oxidase B inhibitor. 5HT: serotonin; HTN: hypertension; max: maximum.Source: References 4, 10.wine, aged cheese, and smoked meat. This reactionpresents as an acute onset of severe headache, nausea,neck stiffness, heart palpitations, chest pain, and confusion.MAOIs can also cause serotonin syndrome. Asmentioned previously, this syndrome most commonlyoccurs when MAOIs are taken concomitantly with otherserotonergic agents such as SSRIs or if venlafaxine, anSNRI, is administered soon after an MAOI. Whenpatients are switched from an SSRI with a short halflifeto an MAOI, it is important that a 2-week washoutperiod be respected between the discontinuation of theSSRI and the start of the MAOI. If fluoxetine is theSSRI, which has a long half-life, the washout periodshould be 5 weeks. 4 Other adverse effects can occur withMAOIs such as orthostatic hypotension, weight gain,sexual dysfunction, and insomnia.Due to the high rate of drug interactions with theseagents, caution should be used when prescribed topatients with asthma using sympathomimetic bronchodilators.In patients with hypertension, MAOIs mayinduce orthostatic hypotension, especially with concurrentdiuretic treatments.Serotonin-Norepinephrine Reuptake Inhibitors 4,10 :The SNRIs such as desvenlafaxine, duloxetine, and venlafaxinemay also be used as first-line agents (TABLE 4).These medications are safer than TCAs, and their adverseeffects are similar to those of SSRIs, including nausea,vomiting, and sexual dysfunction, as well as elevatedblood pressure.Venlafaxine has been shown to cause an increase inblood pressure in 3% to 13% of cases, while desvenlafaxinewas reported to cause an increase in blood pressurein only 1% to 2% of cases. 10 Thus, it is recommendedto avoid using venlafaxine in patients withuncontrolled hypertension since the agent can exacerbatethe condition. Duloxetine has more norepinephrineactivity than both of the aforementioned agents, thusbeing useful with physical symptoms such as muscleaches, headaches, stomach issues, and generalized pain,often occurring with severely depressed patients. Dueto its effectiveness in pain symptoms, duloxetine hasalso been approved for other indications such as fibromyalgiaand diabetic peripheral neuropathic pain. 15 Finally,all three agents have more serotonin than norepinephrineTable 4Serotonin-Norepinephrine Reuptake InhibitorsMedications Initial/Max Dose Comments Adverse EffectsDesvenlafaxine 50 mg/100 mg Active metabolite of venlafaxine;(Pristiq) daily (50 mg max BP elevation reported to be lesseffective dose) common than with venlafaxineDuloxetine 40 mg/ t 1/2= 12 h; moderate inhibitor of(Cymbalta) 60 mg daily CYP2D6; GI adverse effects (nausea,dry mouth, constipation) are common;unique beneficial treatment for physicalpain associated with depressionVenlafaxine 25 mg tid/ 5HT > NE at lower doses; NE > 5HT at(Effexor) 225 mg daily higher doses; t 1/2= 11 h; inhibitor of CYP2D6Similar adverseeffects to SSRIs,except moreincidence of BPelevation withSNRIsBP: blood pressure; 5HT: serotonin; GI: gastrointestinal; max: maximum; NE: norepinephrine; SNRI: serotonin-norepinephrinereuptake inhibitor; SSRI: selective serotonin reuptake inhibitor; t 1/2: half-life.Source: References 4, 10.36U.S. Pharmacist • November 2009 • www.uspharmacist.com