Consult Liaison

  • Clozapine metabolism: If coming in with a major infection, inflammation slows down the CYP metabolization of clozapine. Smoking speeds it up by same means. Cloz/Norcloz ratio should 1.5-2.5 don’t think too much, if wildly out of range like 1 or like 3.

  • With clozapine patients in smokers, move it up or down 1/3 of the dose when they’re returning to vs stopping smoking respectively.

  • If in an inflammatory state in a hospital, clozapine doses should be decreased by 50%


  • Intellectual disability, developmental delay, and dementia patients might get ammonia toxic at levels that are typically within normal


  • For Depakote hyperammonemia, add L-carnitine 660 TID to 990 BID to lower the ammonia, then keep L-carnitine for maintenance


  • Cannabis hyperemesis syndrome can onset even when you cut down just a little. Being relieved by hot showers is pretty pathognomonic


  • In catatonia – check iron because low iron can increase risk of malignant catatonia and worsen response to benzodiazepines


  • Capacity assessment mnemonic, CRAP, stands for Clear and consistent choice. Reasoning. Appreciation. Possesses understanding (risks, benefits, alternatives).

  • Dispositional capacity refers to Agency (can the patient manipulate resources to meet their needs), and Praxis (does the patient have the functional ability to meet their needs) - both of these are assessed when the person is going to be discharged.


  • If you see a very mentally ill person with elevated blood pressure and tachycardia, assess for agitated catatonia


  • Clozapine is the only antipsychotic that you don’t change if someone comes in catatonic because it has so little D2 antagonism


  • For catatonia, need to consider this life threatening. Be checking leg swelling, chest pain, and dyspnea for possible DVTs or PEs, checking blood pressure for hypotension/dehydration, trend their weight for malnutrition. Check for horizontal nystagmus if receiving benzodiazepines - a classic indicator of benzodiazepine exceeding tolerance threshold.

  • IV ativan is preferred for catatonia treatment because of rapid and high peak serum concentrations that thus get into the brain faster. You can add amantadine or memantine (NMDA receptor antagonists, preliminary small amount of evidence supporting utility in catatonia.