Quick SSRI/SNRI Dose Equivalence Tool
Use this calculator to estimate an approximate equivalent dose between common antidepressants. This is an educational antidepressant conversion chart and not a prescription tool.
| Medication | Estimated Equivalent Dose (mg/day) |
|---|
What this antidepressant equivalent dose calculator does
This tool estimates dose equivalence between commonly used antidepressants by mapping each medication to a reference potency anchor. In plain language, it helps answer questions like:
- “If I take 50 mg sertraline, what is a roughly similar dose of escitalopram?”
- “What venlafaxine dose is in a similar range to my current fluoxetine dose?”
- “How can I compare SSRI conversion values before discussing a medication switch with my clinician?”
The result is an approximation only. Equivalent dose is not the same thing as equal side-effect profile, equal withdrawal risk, or equal effectiveness for an individual.
How the calculator works
Each antidepressant is assigned an approximate reference dose associated with a similar therapeutic intensity (anchored to fluoxetine 20 mg/day). The conversion formula is:
Target dose = Current dose × (Target reference dose / Current reference dose)
This approach is commonly used for a first-pass estimate in antidepressant switching discussions, but it does not replace clinical judgment.
Reference anchors used in this page
- Fluoxetine: 20 mg
- Sertraline: 50 mg
- Paroxetine: 20 mg
- Citalopram: 20 mg
- Escitalopram: 10 mg
- Fluvoxamine: 100 mg
- Venlafaxine XR: 75 mg
- Duloxetine: 60 mg
- Desvenlafaxine: 50 mg
- Vortioxetine: 10 mg
- Vilazodone: 20 mg
- Mirtazapine: 30 mg
Why “equivalent dose” is never the full story
An antidepressant dose conversion is only one part of switching medications. Real-world treatment planning also depends on:
- Half-life: Fluoxetine has a long half-life; paroxetine is shorter and may cause more discontinuation symptoms.
- Receptor profile: Drugs with similar depression indications can affect serotonin, norepinephrine, histamine, and other pathways differently.
- Metabolism and interactions: CYP enzyme differences and drug-drug interactions can significantly alter blood levels.
- Patient history: Prior response, side effects, anxiety symptoms, sleep issues, and comorbid conditions matter more than a formula.
- Switch strategy: Direct switch, cross-taper, or washout may each be safer depending on the medications involved.
Practical tips before a medication change
1) Bring a complete medication list
Include prescription medications, over-the-counter products, supplements, and timing of doses. Interaction risk is often hidden in the details.
2) Track symptoms before and after change
Keep short daily notes on sleep, anxiety, mood, appetite, concentration, and side effects. This helps your prescriber determine whether to adjust dose, pace, or strategy.
3) Know urgent warning signs
Seek immediate medical care for severe agitation, confusion, rigid muscles, high fever, suicidal intent, chest pain, or major functional decline.
Frequently asked questions
Is this a substitute for medical advice?
No. This is an educational SSRI/SNRI conversion helper. Prescription decisions must come from a qualified clinician.
Can I use this to stop one antidepressant and start another on my own?
No. Abrupt changes can cause withdrawal effects, relapse, or toxicity. Always discuss a taper/switch plan first.
Why might two “equivalent” doses feel very different?
Because equivalence targets average therapeutic range, not your unique sensitivity, metabolism, diagnosis profile, or treatment goals.