Overview Psychiatric medications can be broken down into the following categories antidepressants antipsychotics mood stabilizers include lithium anxiolytics Mechanism Mood stabilizer Mechanism unknown may be related to inhibition of phosphoinositol recycling in neurons Indications Clinical use mood disorders bipolar disorder for acute treatment of mood episodes and maintenance therapy (prevention of future episodes) major depressive disorder (MDD) adjunctive treatment for some patients who have failed treatment with an antidepressant alone reduces suicide risk in bipolar disorder and MDD SIADH Toxicity and Side Effects Toxicity very narrow therapeutic index requires blood monitoring toxicity may be seen at levels higher than 1.5 mEq/L increased risk in patients who are volume depleted or hyponatremic caution if adding hydrochlorathiazide, NSAID, or ACE-inhibitor loop diuretics do not increase toxicity tremor (coarse tremor indicates likely toxicitiy) sedation ataxia acne edema heart block exclusively excreted by the kidneys (reabsorbed at the proximal convoluted tubule with Na+) and long term use may cause a glomerulopathy hyperparathroidism hypothyroidism polyuria ADH antagonist resulting in nephrogenic diabetes insipidus reason for use in SIADH leukocytosis teratogenesis if given in pregnancy cardiac malformations including Ebstein anomaly in first trimester