09/28/2025
Antidepressant Drugs
1. Selective Serotonin Reuptake Inhibitors (SSRIs)
Examples & Usual Doses
• Fluoxetine: 20–60 mg/day
• Sertraline: 50–200 mg/day
• Escitalopram: 10–20 mg/day
• Paroxetine: 20–50 mg/day
• Citalopram: 20–40 mg/day
Side Effects
• Nausea, insomnia, headache, diarrhea, sexual dysfunction, weight changes.
• Risk of serotonin syndrome if combined with other serotonergic drugs.
Contraindications
• Concomitant use with MAOIs or linezolid.
• Caution in epilepsy, liver disease, and pregnancy (esp. paroxetine – teratogenic risk).
2. Serotonin–Norepinephrine Reuptake Inhibitors (SNRIs)
Examples & Usual Doses
• Venlafaxine: 75–225 mg/day
• Desvenlafaxine: 50–100 mg/day
• Duloxetine: 30–120 mg/day
Side Effects
• Nausea, sweating, hypertension, sexual dysfunction, insomnia.
Contraindications
• Severe uncontrolled hypertension.
• Avoid with MAOIs.
• Caution in liver/kidney impairment.
3. Tricyclic Antidepressants (TCAs)
Examples & Usual Doses
• Amitriptyline: 25–150 mg/day
• Imipramine: 75–200 mg/day
• Nortriptyline: 25–100 mg/day
• Clomipramine: 50–250 mg/day
Side Effects
• Anticholinergic: dry mouth, constipation, blurred vision, urinary retention.
• Sedation, weight gain, orthostatic hypotension.
• Cardiotoxicity in overdose (arrhythmias, seizures).
Contraindications
• Recent myocardial infarction, cardiac conduction defects.
• Glaucoma, urinary retention, severe liver disease.
4. Monoamine Oxidase Inhibitors (MAOIs)
Examples & Usual Doses
• Phenelzine: 15–90 mg/day
• Tranylcypromine: 10–60 mg/day
• Isocarboxazid: 20–60 mg/day
• Moclobemide (reversible, safer): 300–600 mg/day
Side Effects
• Orthostatic hypotension, insomnia, weight gain, sexual dysfunction.
• Hypertensive crisis with tyramine-containing foods (“cheese reaction”).
Contraindications
• Concomitant SSRIs, SNRIs, TCAs (risk of serotonin syndrome).
• Cerebrovascular disease, liver disease.
5. Atypical Antidepressants
Examples & Usual Doses
• Bupropion: 150–300 mg/day (stimulating, no sexual side effects).
• Mirtazapine: 15–45 mg/day (sedating, ↑ appetite & weight gain).
• Trazodone: 50–300 mg/day (sedating, risk of priapism).
• Agomelatine: 25–50 mg/day (good for sleep).
Side Effects
• Bupropion: insomnia, anxiety, seizures (dose-dependent).
• Mirtazapine: weight gain, sedation.
• Trazodone: sedation, dizziness, rare priapism.
Contraindications
• Bupropion: seizure disorders, eating disorders, alcohol withdrawal.
• Mirtazapine: caution in obesity or metabolic syndrome.
Key Point:
• SSRIs & SNRIs = first-line (safer, fewer side effects).
• TCAs & MAOIs = second/third-line (effective but more side effects).
• Atypicals = useful for specific profiles (e.g., bupropion for smoking cessation, mirtazapine for insomnia + depression).
