List the SSRIs
citalopram escitalopram fluoxetine paroxetine sertraline
Compare the half-life of fluoxetine with the other SSRI
usually 2-4 days, most SSRIs are about 1 day
*Norfluoxetine is 7 to 15-day half-life
Which SSRIs have significant CYP2D6 inhibition?
- best: fluoxetine and paroxetine
- modest: sertraline
- no effect: citalopram and escitalopram –> less chance for drug-drug interactions (makes them attractive)
What is unique about paroxetine?
non-linear kinetics so high dose = very high plasma drug concentrations
Which clinical presentation is
most associated with SSRI-induced sexual dysfunction?
- MC with paroxetine, moderate risk with remaining
- both men and women –> decreased libido, difficulty achieving orgasm, erectile dysfunction in 37% of males
Given a patient experiencing SSRI-induced sexual dysfunction, select an appropriate treatment plan for the patient
- switch to non-SSRI bupropion, mirtazapine, nefazodone (serotonin modulator)
- switch to different SSRI
- augment SSRI therapy –> add bupropion/phosphodiesterase inhibitor (Viagra, sildenafil)
NOTE: Bupropion isn’t great as monotherapy but great in combination
Identify drowsiness with SSRI use
17% –> daytime sedation leads to malaise, diminished mental energy, emotional blunting
Identify weight gain with SSRI use and the associated risk for diabetes with long-term use.
- 12% –> unsure if due to SSRI or remission of depression that causes increased appetite/carb craving and change in serotonin receptor activity
- MC with paroxetine
- SSRIs can make them twice as likely to get DM 2 when used >24 months
Identify increased anxiety with SSRI use and the need to treat with anxiolytics in high risk patients
- 11% –> see increase in anxiety/agitation when starting SSRI
- need to anticipate this and treat highest-risk patients with antianxiety meds
- overtime SSRI doesn’t improve anxiety associated with depression
Identify orthostatic hypotension with SSRI use
- all SSRIs will cause a low degree of orthostatic hypotension
- MC with Paroxetine
Identify nausea and vomiting and diarrhea with SSRI use
- nausea: 6% –> all SSRIs associated with transient nausea/GI upset during initiation/dose increase
- nausea is MC with paroxetine/sertraline
- diarrhea is MC with sertraline
Which SSRI is associated with QTc prolongation?
What is the dose in general population
Dosing limit for elderly?
Citalopram
- dose limit in everyone = 40mg/day
- dose limit in > 60 years old = 20mg/day
NOT recommended for patients with bradycardia, hypokalemia, hypomagnesemia, recent MI, uncompensated HF
List the SSRI withdrawal symptoms
- sensory sx: paresthesia, numbness, electric-shock-like sensation, palinopsia (visual trails)
- disequilibrium: light-headedness, dizziness, vertigo
- general somatic sx: ethargy, headache, tremor, sweating, anorexia
- affective sx: irritability, anxiety/agitation, low mood, tearfulness
- GI sx: N/V/D
- sleep disturbance: insomnia, nightmares, excessive dreaming
SSRI withdrawal symptom mnemonic
FINISH:
Flu-like symptoms Insomnia Nausea Imbalance Sensory disturbances Hyperarousal
Which SSRI is most likely to cause withdrawal symptoms?
MC with paroxetine (short half-life), least common with fluoxetine
How would you diagnose serotonin syndrome?
- *serotonergic drug + one symptom cluster:
- spontaneous clonus
- inducible clonus AND agitator OR diaphoresis
- ocular clonus AND agitation OR diaphoresis
- tremor AND hyperreflexia
- hypertonia AND temperature >38°C AND spontaneous/inducible ocular clonus
Serotonergic exposure + rigid muscle tone + dry mucous membranes + dilated pupils + increased bowel sounds + hyperreflexia
