Synopsis mood stabilizers Flashcards
how long to peak serum concentration for lithium
1-1.5 hours for standard
4-4.5 hours for ER
elimination half-life of lithium
18-24 hours
how if lithium metabolized and excreted
it is not metabolized. It is excreted through kidneys
therapeutic indications for lithium
-mania
-bipolar depression
-bipolar maintenance
-MDD
-schizoaffective disorder
0schizophrenia
Lithium onset when treating mania
typically slow. Exerts effect over 1-3 weeks
how do you treat the manic patient in the short term who has been initiated on lithium therapy
give benzodiazepine, DRA, SDA, or valproic acid as well for first few weeks
what should you connsider if a depressive episode occurs in a patient taking lithium
lithium-induced hypothyroidism
substance abuse
noncompliance
use of lithium in schizoaffective disorder and schizophrenia
-prominent mood sx more likely to respond than prominent psychotic symptoms
-useful for augmenting antipsychotics
Lithium in MDD
no more effective than other antidepressants for monotherapy. Usually used as adjunct in nonresponders
what is sodium’s effect on lithium levels
excessive intake lowers levels
hyponatremia causes toxicity
dehydration can cause intoxication
cardiac side effects of lithium
bradycardia and arrythmias
how can you decrease GI upset of lithium
take with food
does lithium cause weight gain? Why or why not?
yes d/t effects on carbohydrate metabolism
OR
d/t lithium-induced:
hypothyroidism
edema
thirst causing increased intake of soda
neuro side effects of lithium
tremor
cognitive effects
what can reduce lithium-induced tremor
propranolol 30-120mg daily (divided)
primidone 50-250mg daily
renal side effects of lithium
polyuria (if severe eval renal function)
polydipsia
thyroid side effects of lithium
goiter, hyperthyroidism, hypothyroidism
Monitor TSH q6 months
what places someone at a higher risk of cardiac side effects from lithium
low salt diet
diuretics/ACEIs
fluid/electrolyte imbalance
renal insufficiency
what are some dermatologic side effects of lithium
worsening of psoriasis
alopecia
early signs of lithium OD/toxicity
tremor
dysarthria
ataxia
GI sx
cardio changes
renal dysfunction
what are later signs of lithium OD/toxicity
loss of consciousness
muscular fasciculations
myoclonus
seizures
coma
how can lithium be removed from the body
kayexalate and miralax but not activated charcoal (GI tract)
hemodialysis
lithium and pregnancy
contraindicated during first trimester d/t risk of birth defects
most common birth defect associated with lithium
Ebstein anomaly
what are some drugs that increase lithium concentrations
carbamazepine, lamotrigine, valproate, clonazepam, thiazide/K-sparing diuretics, ACEIs, NSAIDs
what are some drugs that decrease concentration of lithium
osmotic/loop diuretics, carbonic anhydrase inhibitors, xanthines
can you combine calcium channel blockers with Lithium? Why?
No because of risk of fatal neurotoxicity
how many days prior to ECT must lithium be discontinued
2 days to decrease risk of delirium
starting dose of lithium
300mg TID
labs prior to starting lithium
creatinine, electrolytes, thyroid function tests, CBC, ECG, pregnancy test
how often should lithium levels be checked
every 2-6 months
weekly if dose adjustment. s/s toxicity, suspected noncompliance
how often should ECG be obtained with lithium
annually
effective lithium serum concentration for mania treatment
1-1.2 (associated w/ 1800mg daily)
effective serum concentration of lithium for maintenance
0.4-0.8 (associated w/ 900-1200mg daily)
therapeutic indications for valproate
-bipolar 1 (mania, depression, maintenance)
-schizophrenia
-schizoaffective disorder
what is the black box warning attached to valproate
pancreas and liver dysfunction
symptoms of severe hepatotoxicity with valproate
lethargy
malaise
anorexia
N/V
edema
abdominal pain
what fetal abnormalities are associated with valproate
spina bifida (give folic acid)
heart malformations
weight gain with valproate
common
what drugs can be safely combined with valproate
serotonin-dopamine antagonists and carbamazepine
can you give valproate with lamotrigine? why?
no because of increased risk of steven Johnson syndrome
baseline line labs before starting valproate
hepatic panel. CBC, platelet count, pregnancy test
how often should hepatic transaminase be monitored with valproate
one month after starting therapy then every 6-24 months
therapeutic indications for lamotrigine
bipolar maintenance
major side effect of lamotrigine
steven johnson syndrome (report rash)
what drugs decrease concentration of lamotrigine
carbamazepine
phenytoin
phenobarbital
what if 4+ days of lamotrigine are missed
must start at begining and titrate up again
dosage of lamotrigine for bipolat
100-200mg daily
how long is taper to dc lamotrigine
over 2 weeks, unless rash develops then dc over 1-2 days
half-life of carbamazepine
18-54 hours (average 26)
what happens to carbamazepine’s half-life w/ chronic use (after 3-5 weeks)
it decreases to 12 hours
therapeutic indications for carbamazepine
acute mania
prophylaxis
acute depression
what are some common augmentation meds used with carbamazepine
lithium
valproate
thyroid hormones
antipsychotics
how fast is response usually seen to carbamazepine when using for acute mania
within the first several days of treatment
what are some common side effects of carbamazepine
GI side effects, ataxia, drowsiness
what are some serious side effects of carbamazepine
blood dyscrasias
hepatitis
steven johnson syndrome
renal side effects
what medication should always be coadministered with carbamazepine to women and why
folic acid because of the risk of neural tube defects in pregnancy
major drug interactions for carbamazepine
-decrease concentration of oral contraceptives
-contraindicated w/ MAOIs
-grapefruit juice inhibits metabolism
coadministration of carbamazepine and valproate
valproate displaces carbamazepine so may need to decrease dose and increase dose of valproate
carbamazepine lab interferences
cause decreased TSH
increase total cholesterol
carbamazepine dosage for mania
1200mg daily
dosing carbamazepine with meal
absorption is faster when taken with high-fat meal
contraindications to carbamazepine
preexisting hematologic, hepatic, and cardiac diseases
dosage of carbamazepine with hepatic impairment
1/3 - 1/2 the dose
baseline labs for carbamazepine
CBC w/ platelets
LFTs
electrolytes
EEG (if>40 or w/ preexisting condition)
how often do you monitor labs with carbamazepine
q2 weeks x2 months then quarterly
half life of oxcarbazepine
the parent compound is 2 hours but metabolite (monohydroxide) is 9 hours
most common side effects of oxcarbazepine
sedation and nausea
carbamazepine v/ oxcarbazepine side effects
oxcarbazepine more likely to cause hyponatremia but less likely to develop serious rash
metabolism of oxcarbazepine and drug interactions
-oxcarbazepine induces 3A4 and inhibits 2C19
-3A4 inducers increase clearance and decrease concentration (phenobarbital, alcohol)
excretion of gabapentin
excreted renally unchanged and can be removed by hemodialysis
therapeutic indications for gabapentin
seizures
neuropathic pain
can help w/ social anxiety/panic disorder
what labs will gabapentin create false positives of
amphetamines, barbiturates, benzodiazepines, marijuana
therapeutic indications for topirimate
migraine prevention
obesity
bulimia
binge-eating
alcohol dependence
most common side effects of topiramate
paresthesia
weight loss
somnolence
anorexia
dizziness
memory problems
what drugs do topiramate increase the concentration of
phenytoin
valproic acid
what drugs decreases concentration of topiramate
carbamazepine and phenytoin
what are some off-label uses for levetiracetam
acute mania
adjunct w/ antidepressant
anxiolytic
psych indications for phenytoin
bipolar mania
what is considered second-line treatment for acute mania
calcium channel blockers
