Mood Stabilizers

Question 1

common mood stabilizers

Answer 1

lithium
valproic acid
carbamazepine
lamotrigine

Question 2

less common mood stabilizers

delayed onset, may help w/ manic states of bipolar disorder

Answer 2

risperidone
olanzapine
quetiapine
ziprasidone
aripiprazole

^all second generation, atypical antipsychotics (likely metabolic side effects)

Question 3

Lithium MOA

Answer 3

Reduces Na+ transport (Li+ mimics Na+) and inhibits myo-inositol-1-phosphatase inhibiting inositol recycling

• ->membrane stabilization (dec ion flux = dec APs)
• ->CNS depression

may take days/weeks for full effect

acute sx usually req addnl therapy (Benzos, antipsychotics)

Question 4

Lithium is standard therapy for

Answer 4

mania and bipolar

Question 5

Serum lithium levels are best monitored once the medication has reached a steady state, which is usually after _____ of consecutive dosing.

Answer 5

Serum lithium levels are best monitored once the medication has reached a steady state, which is usually after 4-5 DAYS of consecutive dosing.

Question 6

lithium side effects

initial transient vs. initial persistent

Answer 6

initial/transient: nausea, diarrhea, fatigue

initial/persistent: tremor, weight gain, polyuria, polydipsia

Question 7

Lithium is cleared intact primarily through the ______. Ramifications?

Answer 7

Lithium is cleared intact primarily through the KIDNEYS.

DRIVES BODY TO DILUTE BLOOD
-bc may cause inc blood osmolarity (like Na+) causing
increased ADH release and thirst, but Li+ blocks ADH-receptors in the collecting duct, causing a diabetes insipidus-like state (polyuria)

Question 8

lithium adverse effects

Answer 8

confusion/ataxia (signs of OD)
-may progress to seizures

renal toxicity

thyroid disturbances (mild hypothyroidism)

others: skin rxns, leukocytosis, arrhythmia

Question 9

baseline monitoring tests for lithium

Answer 9

creatinine, BUN (nephrotoxic)
thyroid (hypothyroidism)
electrolytes
ECG

Question 10

Drugs that can increase lithium serum levels, and thus increase the risk for toxicity, include…

Answer 10

ACE inhibitors (captopril, lisinopril)

thiazide diuretics (hydrochlorothiazide, chlorthalidone)

NSAIDs ( ibuprofen, naproxen)

Question 11

Medications that are known to decrease lithium levels include…

Answer 11

K+ sparing diuretics (amiloride)

treats diabetes insipidus effects

Question 12

anticonvulsants as mood stabilizers

possible MOAs

Answer 12

modulation of voltage-dependent ion channels involved in propogating AP

enhancement of inhibitory activity (GABA)

inhibition of excitatory activity
(glutamate, aspartate)

Question 13

What are the risks of anticonvulsants?

Answer 13

CNS side effects (sedation, dizziness, ataxia)

potential inc risk for suicidality

drug interactions

Question 14

valproic acid

Answer 14

Used as a lithium alternative with FASTER onset; acts to inc GABA causing CNS depression

FDA indication for mania and bipolar

narrow therapeutic window

Question 15

valproic acid adverse effects

Answer 15

Similar to Li
- Tremor, sedation, weight gain, nausea, diarrhea;

Others

• alopecia
• teratogenicity: neural tube defects (pregnancy, category D)
• inc in LFTs, can cause fatal hepatotoxicity.

Rarely causes
-platelet dysfunction, PANCREATITIS, agranulocytosis

Question 16

valproic acid requires monitoring of …

Answer 16

valproic acid requires monitoring of liver function and platelet count

Question 17

Carbamazepine

Answer 17

Used if patient is intolerant to both lithium and valproate

MOA: stabilizes Na+-channels, reducing ion flow and AP propagation causing CNS depression

Question 18

Carbamazepine side effects

Answer 18

• bone marrow suppression (aplastic anemia), need CBC monitoring
• produces active, toxic metabolite (10,11-epoxide)
• HLA-based predisposition (asian) –> severe rashes
• Potent CYP450 inducer (requires titration of dose over time, may cause DRUG INTERACTIONS)
• hyponatremia, BC drug enhances ADH release (SIADH) causing fluid retention and dilution of systemic Na+

Question 19

Oxcarbazepine

Answer 19

Carbamazepine derivative drug with less CYP450 induction and no production of toxic metabolite

Fewer overall symptoms except for risk of hyponatremia (poss a bit higher)

Question 20

Lamotrigene

MOA/side effects?

Answer 20

Inhibits excitatory glutamatergic activity

Side Effects:

• Dizziness, ataxia, somnolence, nystagmus, blurred vision.
• Risk of severe rash (can lead to Stevens-Johnson Syndrome), DOSE TRITIATION NEEDED

Question 21

How do anticonvulsants interact with other drugs?

Answer 21

Many anticonvulsant medications undergo extensive hepatic metabolism. They are often substrates as well as inducers of the CYP450 system

Carbamazepine –> potent inducer of this system and will commonly lower serum levels of other substances that are metabolized via similar pathways