Medication Selection Guide for Unipolar Depression
Primary Recommendation
Select any second-generation antidepressant (SSRI, SNRI, or other) based on adverse effect profile, cost, and patient preference—not on efficacy, as all are equally effective. 1
Step-by-Step Selection Algorithm
Step 1: Choose Your First-Line Agent
Since no second-generation antidepressant demonstrates superior efficacy over another 1, your selection should be driven by:
A. Adverse Effect Profile Considerations:
If sexual dysfunction is a concern: Choose bupropion (lowest sexual side effects compared to fluoxetine or sertraline) 1
If patient has psychomotor retardation or chronic pain: Consider SNRIs (venlafaxine, duloxetine) 2
If patient has insomnia or poor appetite: Consider mirtazapine (also has faster onset than fluoxetine, paroxetine, or sertraline) 1, 2
If patient has extreme fatigue: Consider bupropion 2
Avoid paroxetine: Highest rates of sexual dysfunction among SSRIs 1
B. Safety Considerations:
SSRIs carry increased risk for nonfatal suicide attempts compared to placebo 1—monitor closely in first 1-2 months
Venlafaxine: Monitor blood pressure (can cause sustained hypertension); may have greater suicide risk and overdose fatality risk 3
Duloxetine: Check liver function; discontinue if jaundice or hepatotoxicity develops 3
Bupropion: Increased seizure risk 1
C. Cost and Formulary Status
Select the most affordable option within the appropriate class that your patient can access consistently.
Step 2: Initiate Treatment with Close Monitoring
Begin monitoring within 1-2 weeks of starting medication 1
Monitor for:
- Suicidal ideation or behavior (highest risk in first 1-2 months)
- Agitation, irritability, unusual behavioral changes
- Treatment response
- Adverse effects (nausea, sexual dysfunction, sleep disturbance, etc.)
Step 3: Assess Response at 6-8 Weeks
If inadequate response after 6-8 weeks, modify treatment 1
Note: 38% of patients do not achieve treatment response and 54% do not achieve remission with initial treatment 1
Step 4: Second-Step Strategies (If First Treatment Fails)
Both switching and augmentation strategies show similar efficacy—choose based on practical considerations 4
Switching Options:
- Switch to another second-generation antidepressant from a different class
- Switch to cognitive behavioral therapy (CBT)—equally effective as medication switch 4
Augmentation Options:
- Add bupropion SR (lower discontinuation rate due to adverse events than buspirone) 4
- Add aripiprazole (evidence for higher remission rates) 4
- Add cognitive therapy (similar efficacy to medication augmentation) 4
- Add lithium (recommended over combination antidepressants or switching for insufficient response at 4-6 weeks) 5
No evidence supports preferring one second-step strategy over another 1, 4
Step 5: Duration of Treatment
After Achieving Remission:
First episode: Continue for 4-9 months 1
Two or more episodes: Continue for at least 2 years, potentially lifelong 1
Common Pitfalls to Avoid
Don't choose based on perceived efficacy differences—there are none among second-generation antidepressants 1
Don't use paroxetine or fluoxetine in elderly patients—anticholinergic effects and drug interactions 2
Don't forget to monitor blood pressure with venlafaxine/SNRIs 3
Don't continue ineffective treatment beyond 6-8 weeks 1
Don't stop monitoring after initial weeks—suicide risk persists for first 1-2 months 1
Don't underdose or use inadequate trial duration—full therapeutic doses for 6-8 weeks minimum 1
Special Populations
Elderly Patients:
- First choice: SSRIs (avoid paroxetine and fluoxetine due to P450 interactions) 2
- Alternative: SNRIs if psychomotor retardation or pain present (monitor blood pressure) 2
- Consider mirtazapine for sleep/appetite issues 2
- Avoid tricyclics and MAOIs due to anticholinergic effects 2
Severe Depression:
- Combine pharmacotherapy with psychotherapy 5