Pharm - SSRIs

Question 1

List the SSRIs

Answer 1

citalopram
escitalopram
fluoxetine
paroxetine
sertraline

Question 2

Compare the half-life of fluoxetine with the other SSRI

Answer 2

usually 2-4 days, most SSRIs are about 1 day

*Norfluoxetine is 7 to 15-day half-life

Question 3

Which SSRIs have significant CYP2D6 inhibition?

Answer 3

• best: fluoxetine and paroxetine
• modest: sertraline
• no effect: citalopram and escitalopram –> less chance for drug-drug interactions (makes them attractive)

Question 4

What is unique about paroxetine?

Answer 4

non-linear kinetics so high dose = very high plasma drug concentrations

Question 5

Which clinical presentation is

most associated with SSRI-induced sexual dysfunction?

Answer 5

• MC with paroxetine, moderate risk with remaining

- both men and women –> decreased libido, difficulty achieving orgasm, erectile dysfunction in 37% of males

Question 6

Given a patient experiencing SSRI-induced sexual dysfunction, select an appropriate treatment plan for the patient

Answer 6

1. switch to non-SSRI  bupropion, mirtazapine, nefazodone (serotonin modulator)
2. switch to different SSRI
3. augment SSRI therapy –> add bupropion/phosphodiesterase inhibitor (Viagra, sildenafil)

NOTE: Bupropion isn’t great as monotherapy but great in combination

Question 7

Identify drowsiness with SSRI use

Answer 7

17% –> daytime sedation leads to malaise, diminished mental energy, emotional blunting

Question 8

Identify weight gain with SSRI use and the associated risk for diabetes with long-term use.

Answer 8

• 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

Question 9

Identify increased anxiety with SSRI use and the need to treat with anxiolytics in high risk patients

Answer 9

• 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

Question 10

Identify orthostatic hypotension with SSRI use

Answer 10

• all SSRIs will cause a low degree of orthostatic hypotension
• MC with Paroxetine

Question 11

Identify nausea and vomiting and diarrhea with SSRI use

Answer 11

• 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

Question 12

Which SSRI is associated with QTc prolongation?
What is the dose in general population
Dosing limit for elderly?

Answer 12

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

Question 13

List the SSRI withdrawal symptoms

Answer 13

• 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

Question 14

SSRI withdrawal symptom mnemonic

Answer 14

FINISH:

Flu-like symptoms
Insomnia
Nausea
Imbalance
Sensory disturbances
Hyperarousal

Question 15

Which SSRI is most likely to cause withdrawal symptoms?

Answer 15

MC with paroxetine (short half-life), least common with fluoxetine

Question 16

How would you diagnose serotonin syndrome?

Answer 16

• *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