<prompt> Which of the following antidepressants causes sedation and pain relief?VenalafaxineDesipramineAmitriptylineImipramine  <response>: Ans. c Amitriptyline Ref. Harrison 18th p 74. Table 11-1; Table 371-3Painful conditions that respond to tricyclic antidepressants Postherpetic neuralgia Diabetic neuropathy Pension headache Migraine headache Rheumatoid arthritis Chronic low back pain Central post-stroke pain CancerAntidepressantsClassAgentsMechanismSide effects and CommentsTricyclic antidepressants TCAsamitriptyline, Imipramine, nortriptyine desipramineBlock reuptake of NE and 5HT Anticholinergic Alpha blockage Sedation Seizure threshold Overdose: triad 3 Cs: coma, convulsions Drug interactions: do not mix with SSRIs and MAOIs: potentially fatalHeterocylicsamoxopine, bupropion, maprotiline trazodone, mirtazapine, nefazodone venlafaxineMechanism varies Trazodone causes priapism, sedation Amoxapine causes EPS also dopamine receptor blocker Maprotiline, amoxapine, seizures, cardiotoxicity Nefazodone, venlafaxine: P450 inhibitors Bupropion used in smoking cessationSelective serotonin reuptake inhibitors SSRIs fluoxetine, sertraline, citalopram, fluvoxamine, paroxetineBlock reuptake of 5HT Anxiety, agitation, insomnia Nausea Sexual dysfunction Serotonin syndrome muscle rigidity, hyperthermia, myoclonus, ANS instability, seizures occurs with TCADs, MAOIs, meperidine, dextromethorphanMAO inhibitors MAOIsphenelzine, tranylcypromine, isocarboxazidInterferes with metabolism of NE and 5HT by blocking monoamine oxide MAO types A and B Orthostatic hypotention, weight gain Hypertensive crisis if patient consumes food with tyramine and other indirect-acting sympathomimetics Serotonin syndrome when combined with SSRIs 