DBB - Exam 2 - Mood Stabilizers

  1. Bipolar 1 vs. Bipolar 2
    • Bipolar 1: full episode of mania (1 week or more) with symptoms that interfere dramatically with daily routine
    • Bipolar 2: shorter episodes, some symptoms of mania, intereferes a little but not dramatically, does not lead to hospitalization
  2. The 4 phases of treating bipolar
    • Acute: immediate; safety is main concern
    • Subacute: watch carefully, suicide precautions, some antipsychotics
    • Remission: discharged to day hospital or home when still symptomatic but doing better
    • Maintenence: keeping them well long-term; perhaps with mood stabilizers
  3. Which phase of bipolar is more difficult to treat: manic or depressive phase?
  4. Which mood stabilizer is probably more effective at treating the depressive phase of bipolar?
  5. Possible mechanisms of action of lithium
    • Strong effect on second messenger systems (PIP pathway)
    • Influences various transmitter systems
    • Influences calcium homeostasis
    • Influences processes that enhance cell protection and growth
  6. Lithium: mechanism of clearance
    Not metabolized by liver; filtered out completely by kidney
  7. Half-life of lithium
    15-25 hours
  8. Volume of distribution of lithium: high or low?
  9. Therapeutic window of lithium: big or small? What are the consequences of this?
    • Very small therapeutic window
    • Consequence is that blood levels and kidney function must be regularly monitored
  10. As one gets older, lithium doses should be (greater/smaller) due to (increased/decreased) kidney function.
    Smaller; decreased
  11. Lithium: Main drug interactions
    • Certain diuretics (water/blood pressure meds)
    • ACE inhibitors (blood pressure meds)
    • NSAIDS (analgesics)
  12. Hydrochlorothiazide: what is it and what is its interaction with lithium?
    • Diuretic
    • INCREASES reabsorption of lithium by kidneys, DECREASES lithium clearance, INCREASES lithium plasma levels
  13. ACE inhibitors: interaction with lithium
    DECREASES lithium clearance, INCREASES lithium plasma levels
  14. NSAIDS: interaction with lithium
    REDUCES blood flow to kidneys, DECREASES clearance of lithium, INCREASES lithium plasma levels
  15. Side effects of lithium
    • Tremor
    • Renal side effects (decrease kidney function)
    • Thyroid side effects (decreased thyroid function)
    • Weight gain (weight loss less common)
    • GI side effects (nausea, vomiting, diahrrea, etc...)
  16. Lithium and pregnancy: What happens to lithium levels during pregnancy and when during pregnancy? What happens to lithium levels after delivery?
    • During middle trimester, kidney functioning (GFR) INCREASES. 
    • Thus, clearance INCREASES, and lithium levels DECREASE.
    • Therefore, lithium doses should be INCREASED at this point
    • After delivery, GFR decreases rapidly, so lithium dose needs to be DECREASED immediately to prevent lithium toxicity
  17. What is Ebstein's anomoly, when does it occur, and how does it relate to lithium use?
    • Displacement of the tricuspid valve into the right ventricle of the heart (small right ventricle)
    • Occurs during the first trimester
    • Rare illness, but 10x more common with lithium use during pregnancy
  18. Rank in order, from best to worst to use during pregnancy (generally): mood-stabilizing anti-convulsants, antipsychotics, lithium
    Antipsychotics > Lithium > Mood-stabilizing anti-convulsants
  19. Concept of kindling (with epilepsy) and how it relates to bipolar
    • Kindling: frequent, small electrical stimulation can eventually lead to full-blown seizures; the same stimulus over time leads to a more severe effect
    • Bipolar is often characterized as "behavioral kindling"
  20. 3 mood-stabilizing anticonvulsants
    • Valproate
    • Carbamazepine
    • Lamotrigine
  21. Possible mechanisms of action of valproate
    • Influences process that enhance cell protection and growth (lithium has this effect as well, so perhaps this is why valproate has mood-stabilizing effects)
    • Increases GABA synthesis and release
    • Enhances Na+ channel activation (anti-convulsant)
  22. Pharmacokinetics of valproate, Depakote, and Depakote sprinkles
    • Valproate absorbed rapidly
    • Depakote absorbed more slowly
    • Depakote sprinkles - smooth, even absorption curve, but very expensive
  23. Possible mechanisms of action of carbamazepine
    • Enhances Na+ channel activation (anti-convulsant)
    • Anti-manic effects unknown
  24. Carbamazepine Pharmacokinetics
    • AUTO-INDUCTION: Carbamazepine induces the P450 enzyme that metabolizes it
    • Auto-induction increases the clearance
    • After a bit of time, half-life and steady state plasma levels DECREASE due to auto-induction
    • Thus, dose must be INCREASED
    • Usually one dose increase is sufficient
  25. Carbamazepine drug interactions
    Induces activity in enzymes that destroy other drugs, so blood levels of some other drugs may decrease when on carbamazepine
  26. Possible mechanisms of action of lamotrigine
    • Inhibits Na currents
    • Inhibits glutamate release
    • Mood-stabilizing effects unknown
  27. Antipsychotic agents generally used in _______ episodes of bipolar
  28. Concept of polypharmacology
    Often multiple medications needed to treat bipolar
Card Set
DBB - Exam 2 - Mood Stabilizers