Sertraline vs Escitalopram: Comparing SSRIs for Anxiety and Depression

Selective serotonin reuptake inhibitors (SSRIs) are the first-line pharmacological treatment for depression and most anxiety disorders in Australia. Sertraline and escitalopram are the two most prescribed SSRIs in the country, and both are recommended by the Australian Therapeutic Guidelines (eTG) as first-line options. This guide covers how they compare -- but it is important to note that medication choice for mental health is highly individual, and what works best varies significantly between people.

How SSRIs Work

SSRIs increase serotonin levels in the brain by blocking its reabsorption (reuptake) into nerve cells. This makes more serotonin available in the synaptic cleft, which over time helps regulate mood, anxiety, and emotional processing. SSRIs don't work immediately -- it typically takes 2-4 weeks for therapeutic effects to begin, and 6-8 weeks for the full effect.

Sertraline (Zoloft)

• Doses: 25mg, 50mg, 100mg tablets
• Starting dose: typically 25-50mg daily
• Target dose: 50-200mg daily
• TGA-approved for: depression, OCD, panic disorder, PTSD, social anxiety disorder, premenstrual dysphoric disorder (PMDD)
• PBS listed: Yes, for depression and OCD
• Half-life: 26 hours

Sertraline has the broadest range of TGA-approved indications among SSRIs. It is the SSRI of choice in pregnancy (lowest risk of malformations based on available data) and is often preferred for patients with comorbid anxiety and depression.

Escitalopram (Lexapro)

• Doses: 5mg, 10mg, 20mg tablets
• Starting dose: typically 5-10mg daily
• Target dose: 10-20mg daily
• TGA-approved for: depression, generalised anxiety disorder (GAD), social anxiety disorder, OCD
• PBS listed: Yes, for depression and GAD
• Half-life: 27-32 hours

Escitalopram is the S-enantiomer of citalopram (purified active form). It is often considered the "cleanest" SSRI in terms of selectivity -- it has the fewest off-target receptor effects, which generally translates to fewer drug interactions and a straightforward side-effect profile.

Effectiveness: Head-to-Head

The landmark Cipriani et al. 2018 network meta-analysis (published in The Lancet, covering 522 trials and 116,477 participants) ranked escitalopram as one of the most effective and best-tolerated antidepressants overall. Sertraline ranked highly on tolerability and was specifically noted for its good balance of efficacy and acceptability.

• For depression: both are effective first-line options. Escitalopram may have a slight edge in overall efficacy in meta-analyses, but the clinical difference is small
• For generalised anxiety (GAD): escitalopram has the stronger evidence base and TGA approval
• For panic disorder: sertraline has TGA approval; escitalopram is used off-label
• For PTSD: sertraline is the preferred SSRI (TGA-approved; strongest evidence)
• For OCD: both have TGA approval. Higher doses are often needed (sertraline up to 200mg; escitalopram up to 20mg)
• For PMDD: sertraline has TGA approval -- the only SSRI with this specific indication in Australia

Side Effects

Both SSRIs share common class side effects, but there are some differences in emphasis.

Common side effects (both)

• Nausea (most common in the first 1-2 weeks, usually settles)
• Headache
• Sexual dysfunction (reduced libido, difficulty achieving orgasm) -- affects 30-50% of users
• Sleep disturbance (insomnia or drowsiness)
• Weight changes (modest -- typically 1-2kg over 6-12 months)
• Increased anxiety in the first 1-2 weeks (paradoxical but common -- usually settles)

Sertraline-specific

• More likely to cause diarrhoea and GI upset (sertraline has mild dopamine reuptake activity)
• May be more activating (some patients find it energising, which can be good or bad depending on the individual)

Escitalopram-specific

• Dose-dependent QT prolongation -- the TGA has a maximum recommended dose of 20mg. Avoid in patients with known QT prolongation or those taking other QT-prolonging drugs
• Generally considered slightly better tolerated overall (fewer GI side effects than sertraline)

Drug Interactions

Escitalopram has fewer drug interactions than sertraline because it has less effect on cytochrome P450 enzymes. Sertraline is a moderate inhibitor of CYP2D6, which means it can increase levels of some other medications. Neither should be combined with MAOIs, and both require caution with other serotonergic drugs (tramadol, St John's Wort) due to serotonin syndrome risk.

PBS Status and Cost

• Both are PBS listed -- standard co-payment applies
• Generic versions of both are widely available and significantly cheaper than branded versions
• Generic sertraline: approximately $8-$15 per month (PBS)
• Generic escitalopram: approximately $8-$15 per month (PBS)

Starting and Stopping SSRIs

Starting: both should be initiated at a low dose and increased gradually. The first 2-4 weeks are the hardest -- side effects are most prominent before therapeutic benefits appear. Your doctor should review you within 2-4 weeks of starting.

Stopping: taper gradually over at least 4 weeks (longer if you have been on the medication for more than 6 months). Never stop an SSRI abruptly. Discuss any planned changes with your prescribing doctor.

Duration: Australian guidelines recommend continuing an SSRI for at least 6-12 months after remission of a first depressive episode. For recurrent depression, longer-term maintenance treatment may be appropriate.

Choosing Between Them

In practice, the choice often comes down to individual factors and the specific condition being treated.

• You have PTSD, panic disorder, or PMDD (stronger evidence / TGA approval)
• You are pregnant or planning pregnancy (lowest risk SSRI)
• You prefer a more "activating" profile
• Cost is a priority (both are similarly priced, but sertraline has been generic for longer)

• You have GAD (TGA-approved with strong evidence)
• You want the fewest drug interactions
• You are sensitive to GI side effects
• Previous SSRIs caused problematic side effects (escitalopram is often the best-tolerated)

Getting an SSRI Prescribed

SSRIs require a prescription from an AHPRA-registered doctor. Initial assessment for depression or anxiety should ideally include a comprehensive history, validated screening tools (PHQ-9 for depression, GAD-7 for anxiety), and discussion of both medication and non-medication options (psychological therapy is recommended alongside or instead of medication for mild-to-moderate symptoms). For ongoing prescriptions of a stable, well-managed regimen, telehealth is a convenient option for repeat scripts.