Psychiatric Drug Introduction Psychiatric medications can be broken down into the following categories antidepressants antipsychotics bipolar medications anxiolytics Overview Drugs 3° TCAs imipramine amitriptyline doxepin clomipramine 2° TCAs nortriptyline (most well tolerated) desipramine (least histaminic) protriptyline Mechanism block reuptake of NE and serotonin Clinical use major depression enuresis (imipramine) OCD (clomipramine) fibromyalgia painful diabetic neuropathy (amtitryptyline) Side effects anticholinergic tachycardia, urinary retention, flushing, dry membranes, fever, mydriasis 3° TCAs worse than 2° TCAs anti-histaminic sedation desipramine is the least sedating ↓ seizure threshold Toxicity do NOT mix with SSRIs and MAOIs → can be fatal 3 C's of overdose Convulsions Coma Cardiotoxicity (arrhythmias) Brugada pattern (downsloping ST elevation with RBBB) respiratory depression, hyperpyrexia confusion/hallucinations in the elderly due to anticholinergic side effects should use nortriptyline which has lesser SEs Rx for overdose = NaHCO3 sodium load treats CV toxicity (best answer for mechanism) bicarbonate load could improve renal excretion and decrease TCA binding of sodium channels