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Flashcards in bipolar meds Deck (25):

lithium mechanism of action

reduces NE and dopamine sensitivity in CNS
inhibits dopamine synthesis
enhances GABA sensitivity, normalizes levels in CNS
inhibits inositol phosphatase secondary messenger system


SE of lithium

dyspepsia, GI upset, about 20% weight gain, decreased cognition
dose related SE - tremor, sedation, lethargy, polyuria, polydypsia, inc cognitive dulling and GI upset


LI toxicity

>1.5 mEq/L, course tremor/twitching, dizzy/syncope, confusion, slurred speech, ataxia, convulsions, stupor,
>2.5 coma, death


Lithium SE

excreted through kidney, caution with renal failure, dehydration ,NA depletion. , renal damage over 10 years, concentrates in thyroid - hypothyorid, benign heart arrhythmias and bradycardia
rarer-derm psoriasis, alopecia, folliculitis
Diabetes insipidus, leukocytosis


Li drug interactions

ACEi/ARB-inc Li 200-300%
NSAID/Cox2 inh 50%

Inc renal blood flow caused by caffeine/theophylline - dec Li levels


Inc r/f neurotoxicity with Li

antipsychotics, SSRI, TCA, CCB, carbamezapine


Li dosing

intial titration300 BID or TID, check levels 5-77 days after dose change, trough at 8-12 hours after last dose
titration-every 300 mg inc will lead to a 0.3 change in serum levels
as high as 1200-1800
30 to 450 BID is common, lower in elderly, higher when manic


Li therapeutic index

acute; 1.0-1.2 mEg/L
maintenance: 0.6 to 1.0 mEg/L
may take 5-10 days to see therapeutic effects,
maximal effects 2-3 weeks
abrupt withdraw ass. with high relapse rates


Li monitoring

THS, Chem 7 (BUN, Cr, electrolytes) HCG, baseline ECG, Wt, CBC (leukocytosis)


Valproic Acid us and mechanism

wide therapeutic window
preferred in mixed episodes, rapid cyclers
Na channel blocker
decreases glutamine release
stabilizes K channels
enhances GABA activity


valproate to valproic acid: divalproex to valproic acid

stomach; small intestine


valproic acid SE

GI upset (anorexia, nausea, dyspepsia) add H2 antagonist, with food, enteric coated
Dose related SE - elevated liver, resting tremor, sedation, weight gain, somnolence, weakness, HA, thrombocytopenia
Rare SE - hepatic dysfunction, pancreatitis, hyperammonemia, alopecia
Toxicity- tremor, ataxia, nystagmus, visual hallucinations, coma
inc r/f neural tube defects


Valproic acid dosing

initial 500 mg qd to bid
increase every few days, levels every 3-5 days, check 12h after last dose
50-125 mcg seizure control
EC/ER, increase dose by 20%
folic acid supplement in women


Valproic acid monitoring

baseline, monthly for 2 mos, then 3-6 mos, CBC, LFT. weight, amonia (if altered MS), serum levels


Carbamazepine (tegretol)

second line, good for rapid cycling/mixed episodes/atypical presentation
ER - equetro
Mechanism - augmentation of GABA


Carbamazepine SE

occur in 1st mo
dizziness, drowsiness, HA, diplopia, nystagmus, ataxia, blurred vision, nausea, weight gain
transient effects and may resolve with dose reduction
long term - menstrual and infertility problems
rare-SJS, aplastic anemia, agranulocytosis, thrombocytopenia, leukopenia


carbamazepine interactions

potent CYP 450 and 3A4 substrate
Inc CBZ - azole antifungal, macrolides, fluoxetine, fluvoxamine, cimetadine, protease inhibitors
CBZ dec - antidepressants, antipsychotics, benzos, OCP, thyroid hormone, warfarin, phenytoin, felodipine


carbamazepine therapy

start 200 mg BID titrate to response
400-800 mg daily
therapeutic level for seizure 6-12 mg/ml


CBZ lab monitoring

CBC with diff biweekly to monthly for 2 months, then every 3-6 months.
LFT every 6 mo
educate about s/sx of toxicity
fever, sore throat, mouth ulcers, rash, easy bruising


lamotrigine (lamictal)

maintenance of bipolar only
good for rapid cycling
mechanism - inhibits Na channels, inhibits release of glutamate


lamotrigine SE

common - dizziness, tremor, somnolence, HA, nausea, ataxia, diplopia
seizure withdraw in epileptic patients, needs 2 weeks d/c
rare serious SE, SJS, epidermal necrolysis, RASH - assoc with fast titration


lamotrigine dosing

start 12.5 to 25 mg QD
inc 25-50 mg q2 weeks
slow titration to 200-500 mg per day, usually BID
even slower if on valproic acid interaction with CYP 3A4
faster titration inc r/f rash
if stopped for 5 days, must restart at 25 mg again



prodrug of carbamazepine metabolite
second line
initial dosing 300 mg BID, inc to 600 mg/day weekly, to 1200 mg total daily dose
no auto-induction
fewer drug-drug than CBZ
inc metabolism of OCP


antipsychotics and pregnancy

Class C, not associated with teratogenic risk
affects on prolactin and may lead to hyperprolactinemia, infertility
some associated with low birth weight


mood stabilizer indications and classes

indications: bipolar, cyclothymia, schizoaffective, impulse control and intermittent explosive disorders
Classes: lthium and anticonvulsants