What to Expect When Starting Citalopram
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Introduction
Citalopram is a selective serotonin reuptake inhibitor (SSRI) used to treat depression and anxiety disorders. Like all SSRIs, citalopram takes 4-8 weeks to reach full therapeutic effect. Initial side effects often improve before the full antidepressant effect is felt. The FDA limits the maximum dose to 40 mg/day (20 mg/day in patients over 60) due to dose-dependent risk of QT interval prolongation.
Week-by-week timeline
Starting and Early Side Effects
Common early side effects include nausea, headache, dry mouth, insomnia or increased sleepiness, and sexual side effects. Anxiety may temporarily worsen in the first 1-2 weeks before improving — this is a known SSRI effect, especially in anxiety disorders. Starting at a low dose (10-20 mg) and increasing gradually reduces these effects.
Side Effects Improving
Most initial side effects (nausea, headache) improve significantly in the second and third weeks. Some patients notice improved energy or sleep before mood changes. Sexual side effects (reduced libido, delayed orgasm) may persist throughout treatment.
Early Mood Changes
Some improvement in mood, interest, and energy may begin. Sleep quality often improves before daytime depression lifts. Do not give up before 4-6 weeks at the target dose.
Building Toward Full Effect
Antidepressant effects continue to build. Most patients notice meaningful improvement by weeks 4-8. The dose may be increased from the starting dose to the therapeutic range (20-40 mg) if response is insufficient.
Full Therapeutic Effect
Full antidepressant benefit is typically achieved at 8-12 weeks. If there has been partial response, a dose increase within FDA limits (maximum 40 mg, or 20 mg if over 60) may be considered. Continue for at least 6 months after remission to prevent relapse.
When to call your doctor
Contact your healthcare provider if you experience:
- Thoughts of self-harm or worsening depression, particularly in the first weeks (black box warning for under-25s)
- Chest pain, fainting, or irregular heartbeat (QT prolongation risk — more important at higher doses)
- Signs of serotonin syndrome if combined with other serotonergic drugs: agitation, rapid heart rate, fever, muscle twitching, diarrhea
- Severe skin rash, blistering, or fever (rare serious reactions)
- Significant hyponatremia symptoms: headache, confusion, weakness, seizures (especially in elderly patients)
- Unusual bleeding or bruising (SSRIs reduce platelet function)
- Mania or hypomania (especially in patients with undiagnosed bipolar disorder)
Tips for getting started
Take citalopram at the same time each day — morning or evening, whichever minimizes side effects. It can be taken with or without food. To reduce nausea, take with a small meal. Do not stop abruptly — discontinuation syndrome (dizziness, nausea, 'brain zaps', irritability) occurs if stopped suddenly; taper under your doctor's guidance. The maximum dose is 40 mg/day (20 mg/day if over 60) — never exceed this. Avoid alcohol, which worsens depression and interacts with citalopram. Inform your prescriber of all other medications, including supplements (particularly St. John's Wort, which increases serotonin syndrome risk).
Frequently asked questions
More about Citalopram
References
- [Regulatory] FDA Label: Celexa (citalopram hydrobromide) Tablets https://www.accessdata.fda.gov/drugsatfda_docs/label/2012/020822s040s041s042lbl.pdf Accessed 2026-03-01.
- [Regulatory] NIH MedlinePlus: Citalopram https://medlineplus.gov/druginfo/meds/a699001.html Accessed 2026-03-01.
- [Regulatory] FDA Drug Safety: Citalopram and Dose-Related QT Prolongation https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-revised-recommendations-celexa-citalopram-regarding-dose-limitations Accessed 2026-03-01.
Written and fact-checked by PrescriptionDrugs.org Editorial Team
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