Antidepressants

Used to treat depression
Monoamine hypothesis explains how these drugs work
- "People who are depressed do not have enough norepinephrine or serotonin"
- Increasing neurotransmitters should increase the mood
- This is not entirely true
- Most antidepressants are only as effective as placebo in the first 4-6 weeks
  - Plasticity is the other factor resulting in this
  - Amount of neurotransmitters + time passage and neuron adaptation = mood improvements
How to pick the right one
- Trial and error
- Effective Drugs - usually can pick either
  - SSRI
    - Selective serotonin reuptake inhibitors
    - Examples
      - Escitalopram
      - Fluoxetine
      - Paroxetine
      - Sertraline
    - Side effects
      - Sexual dysfunction
        
        Decreased libido
        
        Prolonged ejaculation
  - SNRI
    - Serotonin and norepinephrine reuptake inhibitors
    - Tend to have a more favourable side effect profile but cost more
    - Examples
      - Desvenlafaxine
      - Duloxetine
  - Atypicals
    - Assists with smoking cessation
    - No weight gain as a side effect
      - Avoid use in bulimia due to the pre-existing electrolyte imbalance - will seize faster
      - Seizure threshold will be decreased
    - Examples
      - Bupropriane
    - Side effects
      - Similar to SNRI/SSRIs but milder sexual dysfunction
    - Use case
      - Smoker with mild depressive symptoms
  - Serotonin modulators
    - Not very effective antidepressants
      - More used for the side effect profile
    - Examples
      - Mirtazapine
        
        More effective than Trazadone but not as good as SSRIs or SNRIs
        
        Side effects
        
        Appetite increase - weight gain
        
        Patients who are underweight and mildly depressed
      - Trazadone
        
        Used as a sleep aid
        
        Almost never used as an antidepressant
        
        Side effects
        
        Priapism - painful persisting penile erection that is a medical emergency
- Less effective drugs
  - Tricyclic anti-depressants
    - "Tryptylines" + imipramine + doxepin
    - An extensive list of side effects - can use TCAs for the side effects and not for treating depression
      - Enuresis
        
        Acetylcholine side effects help prevent bedwetting
      - Neuropathic pain (diabetic neuropathy)
      - 3 Cs
        
        Convulsions
        
        Seizures
        
        Cardiac toxicity
        
        Prolonged QT and other arrhythmias
        
        Coma
        
        Altered LOC
  - MAOIs
    - Rarely used for depression
    - Examples
      - Selegiline
      - Phenylezeline
    - Side effects
      - Hypertensive emergency (with the consumption of wine and cheese)
- Rule of 6s with antidepressants
  - Attempt a single dose for 6 weeks and assess in 6 weeks
  - Once an effective dose is found, treat for 6 months even if the mood improves
  - Need 6 weeks of washout
    - Stop one medication and wait 3-6 weeks before starting another one
    - Less relevant now as the drugs are selective
- The goal is to max the dose of a given antidepressant
- Consider psychotherapy in addition to medications

Mood stabilizers

People usually come in with acute mania
- Treated with medications
- Kept on those medications for chronic mania treatment
Acute treatment
- Lithium
  - First-line agent
  - Many side effects
    - Nephrotoxic = renal failure or nephrogenic diabetes insipid us
    - Teratogen
      - Can cause Ebstein anomaly in babies
    - Narrow therapeutic index
- Valproic acid + antipsychotic medication (atypical or 2nd generation)
  - If lithium cannot be used
  - Also a first-line agent
  - Side effects
    - Can lead to spina bifida
    - Valproic acid may not be ideal for women who are trying to get pregnant
      - Neural tube defects in babies
    - Risk of pancreatitis
    - Thrombocytopenia
  - Graulocytosis
Maintenance (chronic treatment)
- Quetiapine
  - Atypical antipsychotic
  - Used in all stages for bipolar treatment
  - Second line agent
  - Side effects
    - Weight gain
    - QT prolongation - get EKG prior to starting
    - Somnolence - can be used to treat mood disorders
- Lamotrigine
  - Second-line agent
  - Risk of Stevens-Johnson syndrome
- Carbamazepine
  - 3rd line agent
  - Should preferably be used for other effects
    - Trigeminal neuralgia
    - Absence seizures in kids

All information provided on this website is for educational purposes and does not constitute any medical advice. Please speak to you doctor before changing your diet, activity or medications.