Pharm Pearls Flashcards
Fluvoxamine is a strong inhibitor of which CYP 450 enzyme?
This could cause toxicity of which asthma drug?
1A2
Theophylline
Is lithium safe during pregnancy?
Not preferred, risk of cardiac malformations including Ebstein’s anomaly
Is Depakote safe during pregnancy?
ValproATE the folATE
Neural tube defects
Dosing consideration when combining Depakote with lamotrigine
Lamotrigine dose must be decreased by 50%
Lamotrigine dosing with carbamazepine, phenobarbital, phenytoin, primidone
Must increase lamotrigine dose by 50% as other drugs are inducers
Lamotrigine dosing Initiation schedule for monotherapy
After how many days of missed doses should lamotrigine dosing go back to beginning?
25 mg daily x 2 weeks
50 mg daily x 2 weeks
Then 100 mg daily on week 5, up to max dose of 200 mg daily starting week 6
If doses are missed 4-5 or more days, must restart again at 25 mg and go through entire schedule
Do not start lamotrigine therapy within two weeks of virus To reduce risk of rash
Viral infection, rash, vaccination. Also avoid new medications, foods, or products during the first three months to decrease risk of unrelated rash. 10% of Patients develop non-severe rash
What is the lithium monitoring schedule
Every 1 to 2 weeks until desired serum concentration has achieved
Then every 2 to 3 months for the first six months
Then Once stabilized every 6 to 12 months
Duloxetine (Cymbalta)
INHIBITS
1A2
2D6
Causes of SIADH (results in hyponatremia)
Symptoms
Carbamazepine
Amitriptyline, morphine, SSRIs
Hypothyroidism
Irritability, nausea, vomiting, muscle weakness, confusion, hallucinations, seizures, stupor, coma
Lithium monitoring
Baseline creatinine TSH and CBC pregnancy test. Steady state achieved after five days. check Li level 12 hours after last dose. once stable check Li every three months and TSH and creatinine every six months.
Ebstein’s anomaly
Therapeutic between 0.6-1.2
Depakote monitoring
Blocks VSSC
Baseline LFT, CBC, coagulation studies, Hcg. Monitor multiple times during first few months, then 6-12 months
Start folic acid supplement and women
Monitoring steady state achieved after 4 to 5 days check valproic acid level 12 hours after last last dose and repeat CBC and LFTs
Starting dose 1000 mg per day for acute mania
Target level between 50 to 100
Potentially fatal hepatotoxicity and pancreatitis, and cardiac fatal in OD
Carbamazepine
First line agent for acute mania and mania prophylaxis. Indicated for rapid cyclers and mixed patients
Baseline LFT, CBC, EKG
Steady state achieved after five days check 12 hours after last dose and repeat CBC and LFTs
Target level 4 to 12
Check level After about a month because it induces it’s own metabolism
Factors predicting a positive response to valproic acid
Rapid cycling patients, female more than male, Comorbid substance issues, mixed pts, and pts with comorbid anxiety is disorders
Better tolerated than lithium
Carbamazepine
Rash
AV conduction delays
Aplastic anemia and Agranulocytosis
CYP3A4 inducer
Risk of SJS
Monitor CBC, LFT, can cause liver damage, can alter warfarin levels, Spina bifida risk with pregnancy
Lamotrigine
Also used for neuropathic/chronic pain
RASH—->SJS
Baseline LFT
If medicine not taken for five days or more, must restart titration at 25 mg daily times two weeks, then 50 mg daily times two weeks, ECT
Three causes of SJS
Lamotrigine, carbamazepine, valproic acid
What happens when mirtazapine is given with clonidine?
They cancel each other out
Mirtazapine’s actions on alpha 2 adrenergic receptors (as an antagonist) cause an increase in NE
Clonidine Is an alpha 2 agonist
What can be used to treat the hypersalivation and dysphasia caused by clozapine?
Clonidine patch
Which class of anti-depressants is most effective in preventing migraines?
Which class of anti-depressants can worsen migraines?
SNRIs Such as venlafaxine have been found to be effective in preventing migraine
SSRI drugs may worsen migraine
What drug when added to Lamictal increases the risk of rash?
Valproate
If a patient develops a rash while taking Lamictal within what periods of time is a drug rash unlikely?
During the first five days of Lamictal treatment and after 8 to 12 weeks of treatment
Approximately 10% of patients will develop a rash, but these rashes are benign
Risk of serious rash is less than 1%
Invega vs Abilify LAI
Invega is better for patients hearing voices
Abilify better in the context of bipolar disorder
What is the antidote for serotonin in serotonin syndrome and what drugs should be avoided?
The antidote is cyproheptadine. Benzodiazepines may be helpful as supportive care.
Avoid dantrolene, bromocriptine, and propranolol
What is the antidote in tricyclic antidepressant overdose?
Sodium bicarbonate
Signs and symptoms of B12 deficiency
Elevated homocystine, elevated MMA (Methylmalonic acid) maybe present in low normal B12 levels, can be an early sign of B12 deficiency. B12 deficiency causes a macrocytic anemia
Symptoms include impaired memory, irritability, depression, dementia, rarely psychosis, paresthesias, peripheral neuropathy
Oral supplementation preferred even in the case of lack of intrinsic factor
What is the effect of combining chamomile with warfarin?
Increased bleeding risk
Major risk of using kava kava for anxiety and insomnia
Liver damage
Which SSRI carries the highest risk for QT prolongation?
Citalopram
Which two medication’s are the only FDA approved treatments for PTSD?
Sertraline, paroxetine
Which Alzheimer’s medication is approved to treat all stages of Alzheimer’s disease?
Donepezil does it All (Aricept)
What is the effect of smoking on olanzapine drug levels?
Smoking reduces olanzapine levels.
