Reading the side effect list for any antidepressant can be unsettling. Dozens of terms, some frightening, with no sense of which ones are likely and which are rare. Celexa (citalopram) is no different. The useful question is not “what could happen?” but “what is likely to happen to me, what will fade, and what needs a phone call today?”
This guide answers those three questions using the actual numbers from the Celexa label, then explains each serious warning in plain language and ends with a clear action guide.
Summary: The side effects most clearly caused by Celexa (more often than placebo) are nausea, dry mouth, sleepiness, sweating, diarrhea, tremor and delayed ejaculation. Many ease within the first few weeks. Serious but uncommon risks include heart rhythm changes, serotonin syndrome, bleeding, low sodium, mania, seizures and angle-closure glaucoma, plus a boxed warning about suicidal thoughts in young people.
Signal versus noise: which side effects are really from Celexa?
Side effect lists usually show how often people on the drug reported a symptom. But people on placebo (dummy pills) report many of the same symptoms, because headaches, poor sleep and stomach upset are common in daily life and in depression itself. The fairest way to read the data is to look at the difference.
The table below uses figures from the Celexa prescribing information, from short-term depression trials of 1,063 people on Celexa and 446 on placebo.
| Side effect | Celexa | Placebo | Extra people affected per 100 |
|---|---|---|---|
| Somnolence (sleepiness) | 18% | 10% | About 8 |
| Nausea | 21% | 14% | About 7 |
| Dry mouth | 20% | 14% | About 6 |
| Ejaculation disorder (men only) | 6% | 1% | About 5 |
| Diarrhea | 8% | 5% | About 3 |
| Sweating | 11% | 9% | About 2 |
| Tremor | 8% | 6% | About 2 |
| Fatigue | 5% | 3% | About 2 |
| Anorexia (reduced appetite) | 4% | 2% | About 2 |
| Agitation | 3% | 1% | About 2 |
| Impotence (men only) | 3% | Less than 1% | About 2 to 3 |
| Yawning | 2% | Less than 1% | About 1 to 2 |
| Decreased libido | 2% | Less than 1% | About 1 to 2 |
| Insomnia | 15% | 14% | About 1 |
| Anxiety | 4% | 3% | About 1 |
Two lessons stand out. First, insomnia was reported almost as often on placebo, so for most people sleep trouble is more likely to come from depression or life circumstances than from Celexa itself. Second, the label notes that headache, dizziness, constipation, palpitations and several other complaints happened as often or more often on placebo.
Overall, 16% of people on Celexa in these trials stopped because of a side effect, compared with 8% on placebo. The most common reasons were nausea, insomnia, sleepiness and dizziness.
Dose matters
In a fixed-dose study comparing 10, 20, 40 and 60 mg, the label reports that fatigue, impotence, insomnia, increased sweating, somnolence and yawning became more common as the dose went up. This is one reason prescribers often go slowly with dose increases and why the lowest effective dose is usually the goal. For a dose comparison, see Celexa 10 mg vs 20 mg.
Side effects that usually fade, and ones that often stay
Usually improve within 1 to 4 weeks
- Nausea: Often worst in the first days. Taking Celexa with food can help.
- Loose stools or mild stomach upset.
- Headache (if it occurs).
- Early jitteriness or restlessness.
- Daytime sleepiness, which often lessens as your body adjusts.
Often persist while you take the drug
- Sexual side effects, such as delayed orgasm or lower desire. See Celexa sexual side effects.
- Sweating, especially at night.
- Dry mouth.
- Emotional blunting, a sense of feeling flat or less able to cry or laugh. This is not in the trial table but is commonly described with SSRIs.
- Vivid dreams or yawning in some people.
Weight
In the short-term trials, people on Celexa lost about 0.5 kg on average compared with no change on placebo. Longer-term experience varies, and some people gain weight as appetite returns with improved mood. See does Celexa cause weight gain.
Ten label warnings explained in plain words
These are uncommon, but they are the reason Celexa comes with a Medication Guide. Knowing them helps you act quickly if something unusual happens.
1. Suicidal thoughts in young people (boxed warning)
In pooled trials of many antidepressants, people under 25 had a higher rate of suicidal thoughts and behaviors than those on placebo: about 14 additional cases per 1,000 patients under 18 and 5 per 1,000 aged 18 to 24. For adults 25 to 64 there was a slight decrease, and for those 65 and older a larger decrease. The risk is highest in the first few months and after dose changes. Celexa is not approved for children.
What to do: Watch for new or worse depression, anxiety, agitation, panic attacks, aggression, impulsive actions or talk of dying. If you have thoughts of suicide, call or text 988 (988 Suicide and Crisis Lifeline) or call 911.
2. Heart rhythm (QT prolongation)
Celexa lengthens the QT interval in a dose-related way. Torsade de pointes, a dangerous rhythm, and sudden death have been reported after marketing. This led the FDA, in its 2012 safety communication, to set a maximum of 40 mg daily, and 20 mg for people over 60, people with liver impairment, CYP2C19 poor metabolizers and those taking CYP2C19 inhibitors such as cimetidine. In the trial ECG data, 0.5% of people on Celexa had a QTc over 500 ms versus none on placebo.
What to do: Report fainting, near-fainting, palpitations or dizziness right away. Tell every prescriber you take Celexa.
3. Serotonin syndrome
Too much serotonin activity can cause agitation, confusion, fast heartbeat, sweating, fever, tremor, muscle twitching or stiffness, and diarrhea. In premarketing trials it occurred in 0.1% of people on Celexa. The risk rises with other serotonergic drugs. See Celexa drug interactions.
What to do: Seek emergency care for these symptoms, especially together.
4. Bleeding
SSRIs reduce platelet serotonin, which increases the risk of bruising, nosebleeds and, more rarely, stomach or other serious bleeding. The risk rises with aspirin, NSAIDs, blood thinners and antiplatelet drugs. Use in the month before delivery is linked to a less than twofold increase in postpartum hemorrhage.
What to do: Report unusual bruising, black stools or vomiting blood.
5. Mania or hypomania
In people with bipolar disorder, an antidepressant alone can trigger a manic or mixed episode. It was reported in 0.1% of trial patients. Prescribers should screen for personal or family history of bipolar disorder before starting.
What to do: Report greatly increased energy, little need for sleep, racing thoughts, unusually grand ideas or reckless behavior.
6. Discontinuation syndrome
Stopping suddenly can cause dizziness, nausea, irritability, anxiety, sensory “zaps,” sleep problems and more. See Celexa withdrawal.
What to do: Do not stop abruptly. Plan any reduction with your prescriber.
7. Seizures
Seizures occurred in 0.3% of trial patients on Celexa and 0.5% on placebo, so the trial data did not show a higher rate. Because people with seizure history were excluded, the label still advises caution in seizure disorders.
8. Angle-closure glaucoma
Pupil dilation from antidepressants can trigger an attack in people with narrow eye angles who have not had preventive treatment.
What to do: Seek urgent care for sudden eye pain, redness, blurred vision or seeing halos around lights.
9. Low sodium (hyponatremia)
Sodium can drop, sometimes severely. Older adults, people on diuretics and people who are dehydrated are at higher risk. Early signs include headache, poor concentration, memory changes, confusion, weakness and unsteadiness.
What to do: Report these symptoms, especially in an older relative who seems newly confused or is falling.
10. Sexual dysfunction
The label now has a dedicated warning on sexual dysfunction. In men it can mean delayed or absent ejaculation, lower desire and erection problems; in women, lower desire and delayed or absent orgasm. It asks prescribers to ask about sexual function before starting and during treatment, because many people never raise it themselves.
Rare and post-marketing reports
After approval, other events have been reported in people taking citalopram or escitalopram. Because these are voluntary reports, it is not possible to know how often they happen or prove they were caused by the drug. They include severe skin reactions such as Stevens-Johnson syndrome, liver injury, pancreatitis, low platelet counts, raised prolactin, akathisia (inner restlessness), priapism, loss of smell and serious allergic reactions including angioedema and anaphylaxis.
Most people will never experience any of these. The value of knowing them is recognizing a serious problem early.
Who is more likely to have side effects?
| Group | Why | What prescribers often do |
|---|---|---|
| Adults over 60 | Celexa exposure is 23% to 30% higher and the half-life 30% to 50% longer | Maximum 20 mg; watch sodium and falls |
| People with liver disease | Clearance falls by 37% and the half-life doubles | Maximum 20 mg |
| CYP2C19 poor metabolizers | Total exposure about double | Maximum 20 mg |
| People on omeprazole, esomeprazole or cimetidine | These raise Celexa levels | Maximum 20 mg |
| People with heart disease or low potassium or magnesium | Higher QT risk | ECG or electrolyte checks; sometimes a different drug |
| People under 25 | Boxed warning on suicidal thoughts | Closer follow-up early on |
| People with bipolar history | Risk of mania | Screening; mood stabilizer may be needed |
Practical ways to ease common side effects
- Nausea: Take with food. Eat smaller meals. Ginger tea or plain crackers can help.
- Dry mouth: Sip water, chew sugar-free gum, and keep up dental care.
- Sleepiness: Ask about switching your dose to bedtime. Avoid driving until you know how you react.
- Insomnia or vivid dreams: Ask about taking it in the morning. See best time to take Celexa and Celexa and sleep.
- Sweating: Breathable clothing, cool bedroom, and mention it if it is severe.
- Jitteriness early on: Usually settles. Tell your prescriber if it is intense or you feel unable to sit still.
- Diarrhea: Stay hydrated. Report if it lasts more than a few days.
Avoid alcohol while you are adjusting, since it can worsen several of these. See alcohol and Celexa.
Side effect or the depression?
Depression and anxiety cause many of the same symptoms listed for Celexa. A rough guide:
- Started within days of the first dose or a dose change: more likely the medicine.
- Present before treatment and slowly easing: more likely the illness, improving.
- New restlessness, agitation or dark thoughts after starting: report quickly, whatever the cause.
Celexa takes time to work, often a few weeks for first changes and longer for full benefit. See how long Celexa takes to work.
Action guide: when to call whom
Call 911 or go to an emergency department
- Thoughts of suicide with a plan or intent, or a suicide attempt
- Fainting, a seizure, or a very fast, pounding or irregular heartbeat
- Fever, rigid or jerking muscles, confusion and heavy sweating together
- Swelling of the face, lips, tongue or throat, or trouble breathing
- Vomiting blood or black, tarry stools
- Sudden eye pain with vision changes
- Severe confusion, hallucinations or extreme unsteadiness
- An erection lasting more than four hours
Call your prescriber within a day or two
- New or worsening anxiety, agitation, panic or irritability
- Signs of mania: little sleep, racing thoughts, reckless behavior
- Easy bruising or frequent nosebleeds
- Headache with confusion or unsteadiness (possible low sodium)
- A rash
- Diarrhea or vomiting that lasts more than a few days
Mention at your next appointment
- Sexual changes
- Persistent sweating, dry mouth or yawning
- Sleep changes that are mild
- Weight changes
- Feeling emotionally flat
You can report side effects to the FDA through MedWatch or by calling 1-800-FDA-1088.
Long-term use: what to keep an eye on
Many people take Celexa for months or years, and the side effect picture changes over time. Early effects usually fade, while a different set of questions becomes more relevant. A yearly review with your prescriber is a good moment to go through these.
| Area | Why it matters with long-term use | What a review might include |
|---|---|---|
| Is it still needed? | Many people need 6 to 12 months or longer after recovery; some benefit from longer use | A discussion of relapse risk versus continuing |
| Dose | Age, new medicines or liver changes can mean the current dose now exceeds the label cap | Checking the dose against the 40 mg and 20 mg limits |
| Heart rhythm | New heart disease or new QT-prolonging drugs can change risk | An ECG if risk factors have appeared |
| Sodium | Risk rises with age and diuretics | A blood test when indicated |
| Bleeding | New blood thinners or regular NSAID use add risk | Review of all pain relievers and anticoagulants |
| Weight and appetite | Changes can be gradual and easy to miss | Weight trend over the year |
| Sexual function and emotional blunting | Often persistent and under-reported | Direct questions and a discussion of options |
| Sleep | Sleep apnea and other problems can develop independently | Screening questions and a sleep history |
If you and your prescriber decide to stop Celexa at some point, plan a gradual reduction. See Celexa withdrawal for what to expect.
Side effects in specific situations
Pregnancy and after birth
The label describes possible complications in newborns exposed to SSRIs late in pregnancy, including breathing and feeding problems, and a rare risk of persistent pulmonary hypertension of the newborn. It also notes that stopping antidepressants during pregnancy raises the chance of depression returning. These decisions belong with your obstetric and mental health teams. For nursing parents, see Celexa while breastfeeding.
When combined with alcohol
Alcohol adds to sleepiness and dizziness and can deepen low mood. See can you drink alcohol on Celexa.
During illness with vomiting or diarrhea
Fluid and electrolyte loss can lower potassium and magnesium, which raises QT risk, and dehydration can contribute to low sodium. If you are unwell for more than a day or two, mention Celexa to whoever treats you.
After a dose increase
Some early side effects can return briefly for a week or two after the dose goes up. The boxed warning also asks for closer watching for mood changes after any dose change.
How to describe a side effect so it gets taken seriously
Vague complaints are easy to miss in a short appointment. A clear description helps your prescriber act. Try to cover:
- What it is, in your own words.
- When it started, relative to starting Celexa or a dose change.
- How often and how long it lasts.
- How much it affects work, sleep, relationships or safety, on a 0 to 10 scale.
- What you have tried, such as taking it with food or changing the time.
- Anything else that changed: new medicines, supplements, alcohol, illness or stress.
For more plain-language information on citalopram’s side effects and precautions, see the MedlinePlus citalopram page.
Frequently asked questions
Can Celexa cause headaches?
Headache is commonly reported by people taking Celexa, but in the trials it was reported about as often on placebo. If headaches are new, severe or come with confusion or unsteadiness, tell your prescriber, since low sodium can be a cause.
Does Celexa cause dizziness?
Some people feel light-headed, especially early on or when standing quickly. Dizziness with palpitations or fainting needs prompt attention because of the QT warning.
Can Celexa side effects start after months of taking it?
Most start early, but some, such as low sodium, bleeding linked to a new medicine, or a QT problem after a new interacting drug, can appear later because something else changed. New symptoms at any point are worth reporting.
Do Celexa side effects go away if I lower the dose?
Dose-related effects such as sleepiness, sweating, yawning and some sexual effects often ease at a lower dose. Any change should be planned with your prescriber, because lowering the dose can bring back symptoms.
What is the most common side effect of Celexa?
Nausea, dry mouth and sleepiness are reported most often. The side effect most clearly linked to Celexa compared with placebo is delayed ejaculation in men.
How long do Celexa side effects last?
Early effects such as nausea and jitteriness often ease within one to four weeks. Sexual effects, sweating and dry mouth may last as long as you take it.
Does Celexa cause anxiety at first?
Some people feel more anxious or restless in the first week or two. In trials, anxiety was only slightly more common than on placebo, but agitation was about twice as common. Report it if it is intense.
Is Celexa hard on the heart?
Celexa has a dose-related QT effect, which is why the maximum dose is capped. For most healthy adults at standard doses, the risk is low. People with heart disease or other risk factors need more care.
Can Celexa cause memory problems?
Impaired concentration and memory lapses are listed as frequent in the broader trial data, and depression itself affects memory. New confusion, especially in older adults, can signal low sodium and should be checked.
Does Celexa cause hair loss?
Hair loss is listed as infrequent. If you notice it, talk to your prescriber, since thyroid problems, iron levels and stress can also cause it.
Are Celexa side effects worse than Lexapro?
The two are closely related and share most side effects. Celexa has a larger QT effect at commonly used doses. See Celexa vs Lexapro.
A quick self-check after your first two weeks
Around the two-week mark, many people find it useful to take stock. Ask yourself:
- Which side effects have eased, and which are the same or worse?
- Is anything affecting my safety, such as sleepiness while driving or dizziness on stairs?
- Have I noticed any new agitation, panic or dark thoughts?
- Am I taking Celexa every day at about the same time?
- Have I started anything new, including over-the-counter products or supplements?
- Has my alcohol or caffeine intake changed?
Write the answers down and share them at your next check-in. If anything on the urgent list above applies, do not wait for the appointment.
The bottom line
Most Celexa side effects are mild and temporary: nausea, dry mouth, sleepiness, sweating and some stomach upset. Sexual effects are common and often persistent. Serious risks are uncommon but important: heart rhythm changes, serotonin syndrome, bleeding, low sodium, mania, eye pressure problems and suicidal thoughts in young people. Knowing which is which lets you ride out the expected effects and act fast on the rare ones.
This information is educational and does not replace advice from your healthcare provider. Do not stop taking Celexa without talking to your prescriber.
