Fluoxetine (Prozac, Sarafem) Flashcards
Brands (3)
- Prozac
- Prozac weekly
- Sarafem
Class
SSRI (serotonin 1A)
Uses
- Major depressive disorder (8 yr+)
- OCD (7 yr+)
- PMDD
- Bulimia
- Panic disorder
- Bipolar depression (along with Olanzapine)
- Treatment resistant depression (with Olanzapine)
- Social anxiety disorder
- PTSD
MOA
- Selective serotonin 1A reuptake inhibitor
- Blocks serotonin reuptake pump
- Desensitizes serotonin receptors
- Also antagonizes serotonin 2C receptors (which increase NE and DA transmission)
Onset of action
- 2-4 weeks
- may cause increased energy initially
- if nothing after 6-8 weeks, increase dose or change
If it works
- If first episode - continue till 1 year after all symptoms gone
- If second or more- continue indefinitely
If it doesn’t work
*Dose change, switch or augment in case of partial response, no response or no longer responding
Augment with
*Insomnia - Trazodone
*Depression persists - Can add bupropion, mirtazapine, reboxetine, atomoxetine
*Fatigue, sleepiness, lack of conc - Modafinil
*Bipolar- Mood stabilizers or atypical antipsychotics
FLUOXETINE + OLANZAPINE is EXCELLENT combo for bipolar depression, psychotic depression, t/t resistant unipolar depression
*Anxiety- Gabapentin, Tiagabine
S/Es, why they happen
*Caused due to inc serotonin in receptors in other parts of brain and body -
sleep centers - insomnia
gut - diarrhea
- inc serotonin can dec dopamine release - emotional flattening, cognitive slowing, apathy
- Serotonin 2C antagonism - anxiety, agitation
- Notable S/Es-
- Sexual dysfunction.
- GI - N/V, constipation, diarrhea, dry mouth
- CNS - insomnia, sedation, agitation, tremors, headache, dizziness
- Sweating, bruising, SIADH
*Rare-
seizures
induce mania
suicidal ideation (less than 24 y/o)
What to do about S/Es
- wait
- If insomnia - take in morning
- reduce dose to 10, then keep at 10 or increase to 20
- switch or augment
- sexual dysfunction - Bupropion, sildenafil, vardenafil, tadalafil
Dosing
*Depression 20-80 mg
Anxiety, OCD 20-80 mg
Start at 20 in morning, assess in a few weeks, inc upto 80 max
*Bulimia 60-80 mg in morning
*Forms - capsule 10, 20, 40, 60 mg tablet 10 mg liquid 20 mg/5 ml - 120 ml bottles weekly capsule 90 mg
Dosing tips
- Once daily orally, usually in morning
- weekly may inc compliance
- more anxious pt - low starting dose, slow titration
OD, Taper or not
Rarely lethal in mono therapy OD
Resp depression, esp with alcohol, ataxia, sedation, seizures
Taper rarely necessary due to long half life
Half life parent drug
2-3 days
Half life metabolite
Norfluoxetine - 2 weeks
CYP action
Inhibits CYP450 2D6 and 3A4
DI with Tramadol
Seizure risk high
DI with TCAs
can inc TCA levels
DI with MAOIs
- Fatal serotonin syndrome - no overlap for 14 days after MAOI stopped.
- Don’t use MAOI for 5 weeks after stopping fluoxetine.
DI with warfarin
Can displace it from protein - inc warfarin level - bleeding, bruising risk
NSAIDs + SSRIs
NSAIDs reduce effectiveness of SSRIs
DI due to CYP 2D6 action
- Inhibition could interfere with analgesic action of codeine
- Inhibition inc plasma levels of beta blockers and atomoxetine
- Inhibition inc conc of thioridazine - cardiac arrhythmia
DI due to CYP 3A4 action
Inhibits CYP 3A4 -
- inc level of alprazolam, buspirone, triazolam
- inc pimozide - QTc prolongation - cardiac arrhythmia
Inhibit HMG CoA reductase inhibitors -
- inc conc of simva, atorva, lovastatin - rhabdomyolysis
- no effect on prava, fluvastatin
DI with Diazepam, Trazodone
can inc their levels by reducing clearance
Precautions
- Cautious to start another antidepressant for upto 5 weeks after stopping fluoxetine
- Cautious with seizure history pts
- Cautious in bipolar pts
- Warn about suicidal ideation, esp in kids
C/I
Don't give with *MAOI * thioridazine *pimozide *tamoxifen Allergic
Renal, hepatic, cardiac pts
- Half dose in hepatic impairment pts
* Safe and even protective in MI/Angina pts, improve survival and mood
Elderly, Kids, Pregnancy, BF
Same as Sertraline
Advantages
- Atypical depression (hypersomnia, inc appetite)
- fatigue and low energy
- comorbid eating disorder
- Generic less expensive than brand name
- weekly administration possible
- kids with OCD or depression
Disadvantages
- Anorexia
- starting t/t in anxious, agitated pts
- starting t/t in severe insomnia
Target symptoms
- depressed mood
- energy, motivation, interest
- anxiety (can inc short term anxiety in the beginning tho)
- sleep disturbance (can inc short term)
Of note
- Maybe first choice for atypical depression
- Avoid in agitated insomniacs
- Not as well tolerated for panic disorder, anxiety disorder
- long half life, even longer metabolite half life
- Helpful in mood disorder with eating disorder
