antidepressants

Question 1

NNRIs/TCA

MOA

Answer 1

Block the reuptake of serotonin and norepinephrine at the presynaptic neuron =

• Elevated mood
• Increased activity and alertness
• Improved appetite
• Improved sleep

Block histamine and acetylcholine receptors = side effects

Block alpha adrenergic and Na+ channels

Question 2

TCA Side effects

Answer 2

Block histamine and acetylcholine receptors = side effects
Weight gain, drowsiness, dry mouth, constipation and blurred vision

Also increase risk for overdose death (2 week supply can be lethal)

Block alpha adrenergic and Na+ channels
Lead to cardiac arrhythmias = contraindicated with CV disease
Consider baseline ekg with periodic monitoring

Question 3

TCA Indications

Answer 3

Depression
Obsessive compulsive disorder
Chronic pain

Question 4

TCA Pearls

Answer 4

Administer at bedtime due to drowsiness

2-4 weeks to see full effect

Caution in the older adult due to anticholinergic effects
(on Beers List, Fall Risk)

Sexual side effects, weight gain

Question 5

SSRIs MOA

Answer 5

Potent inhibitors of serotonin reuptake in the presynaptic cell
Each SSRI also mildly affects other neurotransmitter reuptake which contributes to individual side effect profiles and patient responses
Escitalopram and citalopram are the most neutral

No blockage of histaminic, cholinergic receptors or NA+ pump = fewer side effects

Question 6

SSRI Side effects

Answer 6

Nausea
Lightheadedness
Headache
Sedation/sleep disruptions
Increased sweating
Agitation
Sexual side effects
Weight change

Often transient and resolve within a couple of weeks (exception of sexual and weight gain SE)

Question 7

SSRIs Prescribing Pearls

Answer 7

Never use w/MAOI and use caution with migraine medications (triptans), St. Johns Wort = serotonin syndrome

Long 1/2 life agents have a lower chance of discontinuation syndrome (fluoxetine) = good in the elderly or those who frequently forget to take medications

Generally recommend remaining on the medication for 6-9 months if effective

Suicide risk: higher incidence of suicidality in the first 3 weeks of treatment

Citalopram can prolongate the QT segment

Question 8

SSRI Dosing

Answer 8

Lexapro 10-20
Celexa 20-40
Prozac 20-80
Paxil 20-50/60
Zoloft 50-200

Question 9

SNRIs Pearls

Answer 9

More activating than SSRIs = good for “sluggush” depression

Must monitor BP as can cause HTN

Duloxetine is also FDA approved for neuropathic pain
Monitor LFTs with duloxetin

Question 10

SNRIs Side effects

Answer 10

headache, nausea, dizziness, insomnia, dry mouth, constipation, sexual dysfunction

Must wean slowly – can cause significant withdrawal symptoms

Question 11

NDRIs (Bupropion)

Answer 11

inhibition of norepinephrine and dopamine reuptake

Effective for patients who cannot tolerate side effects of SSRIs such as sexual dysfunction, non-responders to SSRIs or augmentation of SSRI therapy

Good for patients with depression and:
hypersomnia
Increased appetite
Fewer sexual side effects, appetite suppressant

Question 12

NDRI Side effects

Answer 12

Insomnia, jitteriness, weight loss, irritability, headache, dry mouth
Can exacerbate anxiety
Lowers the seizure threshold = absolute contraindication for anyone who has ever had a seizure