Pharmacokinetics: psychotropic drugs Allie Punke (apunke@uthsc.edu)

TCA Psychotropic drugs

TCA AB is a 75 YO patient who is going to be initiated on a TCA. The physicians asks for your recommendation on which TCA to initiate. What class (secondary or tertiary) do you recommend?

TCA Secondary: Tertiary: Examples: Primarily (NE or serotonin): Metabolism: Active or inactive metabolites: Tertiary:

tca A patient is admitted to the hospital due to overdose of amitriptyline. Is hemodialysis an option? Distribution: Lipophilic or hydrophilic Plasma protein binding

tca Increase or Decrease TCA levels? Carbamazepine Promethazine Elderly Smoking Fluoxetine Chronic alcohol use Birth control pills Phenytoin Barbiturates

tca Due to your previous recommendation, AB was initiated on nortriptyline (takes at 8 pm daily). When should we schedule a follow up appointment with him to draw a nortriptyline level? What is considered a therapeutic level? If the patient was on imipramine instead, what labs would we want to order? Collect at least 5 days after initiation (half life is 20 hours). 12 hours post dose to allow for distribution into tissues.

SSRI Psychotropic drugs

SSRI SSRI’s are first line to use for anxiety; they are safer than TCAs, especially if the patient overdoses. BK is a 25 YO female who balances working 2 part time jobs and attends college. Due to her busy lifestyle, she admits to not taking her medications at the same time every day and occasionally forgets her medications. Which SSRI (name and dose) should we initiate for her?

SSRI BR is a 26 YO female who reports feeling very anxious throughout the day which affects her appetite (often doesn’t feel like eating). Additionally, she notes that she has a hard time sleeping due to not being able to “shut off her brain” at night. Which SSRI should we initiate for her? TR is a 30 YO male who recently moved back into his parents house. He reports he has difficulty getting out of bed and starting his day due to depression. Which SSRI should we initiate for him?

SSRI Which enzyme are SSRIs metabolized by? Which SSRIs are responsible for drug-drug interactions due to inhibition of a CYP enzyme?

SNRI Psychotropic drugs

SNRI What physiologic response can SNRIs cause that should be monitored in patients (due to MOA)? Venlafaxine is metabolized by CYP 2D6 to what active metabolite? Duloxetine also had indications for what other conditions?

lithium Psychotropic drugs

lithium BZ is a 24 YO male who was diagnosed with bipolar disorder. He comes to your pharmacy to pick up his new prescription for lithium. What are some acute side effects to counsel him about? What dose was he mostly likely prescribed? What is the goal therapeutic level? Ideally, how long should we wait after the patient took the last dose to draw a level?

lithium BZ is experiencing GI distress, lack of coordination, and lethargic. Since the patient is on lithium, an appropriately timed lithium level is ordered and results as1.6. Which of the following is the patient experiencing? Mild toxicity Moderate toxicity Life threatening toxicity Can we consider using hemodialysis to lower the lithium concentration?

lithium

lithium DY is a 35 YO male who was diagnosed with bipolar disorder and is being managed on lithium. He recently completed the Boston marathon. Due to probable sodium depletion from running, what is the effect on the lithium level (increased or decreased)? A 24 YO female in pharmacy school has been consuming extra caffeine in order to prepare for an exam. How will this affect her lithium level?

lithium Which of the following will result in a decreased lithium concentration? A. NSAIDS B. ACEI C. Decrease in sodium intake D. Increase in sodium intake What type of diuretic affects lithium? Does it increase or decrease lithium levels?

summary TCAs= ___________ for elderly patients due to no _______ metabolites. SSRIs= _________ if not adherent to medication regimen. ___________ is the most sedating. ________ does NOT need to be tapered, due to the long half-life. If a drug is metabolized by ________, a drug interaction is likely if combined with fluoxetine and paroxetine. _______ is the starting dose for fluoxetine with a max of ______. _______ is the starting dose for sertraline for a young healthy patient, whereas the starting dose for a geriatric patient is _____.

summary NSAIDS/ACEI, thiazides, and decreased sodium intake all result in ________ lithium levels. Caffeine, theophylline, increased sodium intake all result in _________ lithium levels. Patients should be counseled regarding _______ and _______ because these can affect lithium levels.

summary Mild toxicity= _______ lithium level Moderate toxicity=__________ lithium level Life-threatening toxicity= _________ lithium level Acute therapeutic range=______ Chronic therapeutic range=______

Questions? Enjoy your weekend!