Celexa Side Effects: What's Common and What Needs a Call
The most common Celexa (citalopram) side effects are nausea, dry mouth, sleepiness and sweating.
By withClaro Editorial · 2026-11-02 · 4 min read
Clinical section reviewed by Dr. Jason Tan , Consultant Psychiatrist, on October 27, 2026.
Key takeaways In the FDA trials, nausea affected 21% of people on Celexa against 14% on placebo, and sleepiness 18% against 10%. Ejaculation problems affected 6% of men against 1% on placebo, the only side effect at 5% or more that was at least twice the placebo rate. In 100 Reddit threads, tiredness and feeling anxious or jittery were the side effects people named most. The label caps the dose at 40 mg, or 20 mg for people over 60 and some others, because of heart rhythm risk. On this page
What are the most common side effects of Celexa? What people on Reddit say they felt on Celexa Which Celexa side effects pass, and which need a call? What is the Celexa heart warning? What should you tell your prescriber about Celexa side effects? The most common Celexa (citalopram) side effects are nausea, dry mouth and sleepiness; in men, ejaculation problems stand out most against placebo. The FDA numbers come from depression trials of up to six weeks, at doses from 10 to 80 mg, and several side effects grew with the dose. Many early effects ease within the first weeks.
What are the most common side effects of Celexa?
Sleepiness, nausea and dry mouth are the common ones with the clearest gap over placebo; in men, ejaculation problems have the biggest gap of all. The label compares 1,063 people on Celexa with 446 on placebo:
Side effect, by gap over placebo Celexa Placebo Sleepiness 18% 10% Nausea 21% 14% Dry mouth 20% 14% Ejaculation problems (men only: 425 on Celexa, 194 on placebo) 6% 1% Diarrhea 8% 5% Tremor 8% 6% Sweating 11% 9% Tiredness 5% 3% Insomnia 15% 14%
Insomnia and sweating were almost as common on placebo in the trials, so these figures can't say whether they come from the medicine for any one person; if you have them, mention them to your prescriber. Less common reactions were also about twice the placebo rate, such as loss of appetite (4% against 2%) and agitation (3% against 1%). In a fixed-dose study, tiredness, impotence, insomnia, sweating, sleepiness and yawning rose with the dose, so they are less likely on 10 mg than on 40 mg.
What people on Reddit say they felt on Celexa
Tiredness and feeling anxious or jittery, named by 18 people each. We read 100 recent threads where people discussed citalopram side effects, comments included, and 71 people described their own experience. These are people's own accounts, and people with ongoing problems are more likely to post, so treat this as a range of experiences rather than odds. Of the 71, 58 named at least one side effect, 4 said they had none, and the rest didn't say. The table counts the 58 who named one:
What they named Of 58 people Tiredness or drowsiness 18 Anxiety or jitteriness 18 Trouble sleeping 11 Nausea or stomach trouble 9 Lower libido or orgasm problems 9 Emotional flatness 9
Some changes did fade. One person on Reddit wrote:
I felt emotionally very numn at first with Celexa. But after about two weeks my emotions were back; the good ones were normal and the anxious ones were very muted.
Which Celexa side effects pass, and which need a call? Medically reviewed by Dr. Jason Tan on October 27, 2026, this section only.
Most early side effects ease, but a few tend to last and some need a call the same day. Tiredness and anxiety stood out more on Reddit than in the trials, where they affected 5% and 4%. Most early effects ease, but some people online describe side effects lasting months; telling a lingering side effect from something else is a job for your prescriber. Heart symptoms, such as fainting or a pounding, irregular heartbeat, also need a call the same day. The clinical view:
Most early side effects of antidepressants ease within the first weeks, while a few tend to last and are worth raising.
Side effects that often pass include nausea, an upset stomach, headache, sleep changes and feeling restless. If sexual side effects, weight change or feeling emotionally flat appear, they tend to stay while you take the medication. A change of dose or medication often helps with these, so mention them instead of putting up with them.
Call your prescriber the same day, or get urgent care, if you notice:
- new or worse thoughts of suicide or self-harm, especially early on, after a dose change, or in people under 25 - agitation, heavy sweating, fever, muscle twitching or confusion, which can be signs of serotonin syndrome - unusual bleeding or bruising, black or tarry stools, or vomiting blood - a sudden burst of energy, little need for sleep, racing thoughts or unusual risk-taking, especially if you or a close relative has bipolar disorder If you're having thoughts of harming yourself, contact emergency services or a crisis line straight away. In the US, call or text 988. In the UK, call Samaritans on 116 123. Elsewhere, find a crisis line near you .
What is the Celexa heart warning?
Citalopram has its own heart warning. It can lengthen the QT interval, the time on an ECG from the heart's main pumping beat to the end of its recovery, and the effect grows with the dose. Chest pain, shortness of breath, severe dizziness, fainting or a pounding, irregular heartbeat need help the same day. The label asks for it to be avoided, unless the benefit outweighs the risk, in people with congenital long QT syndrome, a slow heart rate, a recent heart attack or heart failure that isn't under control, low potassium or magnesium, or other medicines that lengthen QT; with pimozide it must not be used at all. That is a decision for your prescriber, not one to make on your own.
What should you tell your prescriber about Celexa side effects?
Tell your prescriber which side effects you have, when they started and whether they are easing. It helps to tell them:
When you started Celexa, your dose and any recent change. Which side effects you have and how strong they are. Any palpitations or dizzy spells, even if they passed. Other medicines you take, including antibiotics and antipsychotics. Whether anxiety rose after starting. More on doses in Celexa dosage .
Download on the App Store Side effects on Celexa rise and fade over weeks, and a daily record shows which ones are easing. The withClaro app lets you log mood, sleep, energy and side effects each day, linked to your dose, and turns it into a report for your prescriber.
Frequently asked questions Does Celexa make anxiety worse at first? Some people feel more anxious early on; on Reddit it was one of the two side effects named most. Note when it started and how bad it gets, and tell your prescriber if it's hard to manage.
Why is Celexa limited to 40 mg? Higher doses raise the risk of heart rhythm changes. For people over 60, people with liver problems and people who process citalopram slowly, the limit is 20 mg, so ask your prescriber which applies to you.
Does Celexa cause sexual side effects? They're common with SSRIs, including Celexa: in men, ejaculation problems were six times as common as on placebo. Say which part changed, desire, arousal or orgasm, when you raise it with your prescriber.
Does Celexa sleepiness go away? Many early side effects ease in the first weeks, and sleepiness is one that can. If it keeps affecting your days, note when it hits and ask your prescriber whether a change of time or dose fits you.
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Sources CELEXA (citalopram) prescribing information, US Food and Drug Administration via DailyMed MedlinePlus: Citalopram Claro articles are for self-monitoring and educational purposes only. They are not a medical device, therapist, or diagnostic tool, and do not replace care from your prescribing clinician. If you are in crisis, contact your care team, emergency services, the Samaritans (UK: 116 123), or the Crisis Text Line (US: text HOME to 741741).