Quick answer: The usual adult Celexa dosage is 20 mg once a day. After at least one week, a prescriber may raise it to 40 mg once a day, which is the maximum. For people over 60, people with liver problems, slow CYP2C19 metabolizers, and anyone taking cimetidine or another CYP2C19 inhibitor, the ceiling is 20 mg a day.
Celexa dosage spans a narrow range, and the reasons behind it matter. Most antidepressants have a lot of room between the starting dose and the top dose. Celexa (generic name citalopram) has very little. Most adults start at 20 mg, the cap is 40 mg, and some groups should never take more than 20 mg. Before 2011 the label allowed up to 60 mg a day. Then heart-rhythm data changed the rules.
This guide works like a ladder. Each rung is one dose, and each rung lists who it fits. It covers how a typical increase happens, how to take your tablets or liquid, what to do after a missed or extra dose, and how switching between antidepressants is usually handled. Every number here was checked against the current FDA-approved prescribing information. Your prescriber’s instructions always come first.
Citalopram is a selective serotonin reuptake inhibitor (SSRI). In the US it is approved for major depressive disorder in adults. AbbVie sells the Celexa brand, and generic citalopram is widely available. If you are still deciding whether this medicine is right for you, our guide to common and serious Celexa side effects is a good place to start. This page sticks to the numbers.
Celexa dosage quick-reference table
The table below sums up the dosing section of the official Celexa prescribing information from AbbVie (revised October 2023). It matches current generic citalopram labels on DailyMed.
| Rung | Daily dose | Who it applies to | Key rule |
|---|---|---|---|
| Low start (prescriber’s choice) | 10 mg | Some people sensitive to side effects, sometimes used as a gentler first step | Not the labeled starting dose; your prescriber decides |
| Standard start | 20 mg once daily | Adults with major depression | Take with or without food |
| Ceiling for higher-risk groups | 20 mg once daily (max) | Over 60, liver impairment, CYP2C19 poor metabolizers, taking cimetidine or another CYP2C19 inhibitor | Do not go above 20 mg |
| Top dose | 40 mg once daily (max) | Adults who need more than 20 mg and have none of the risk factors above | Raise no sooner than 1 week after starting |
| Above the ceiling | More than 40 mg | No one | Not recommended because of QT prolongation risk |
Available strengths and forms
- Tablets: 10 mg, 20 mg and 40 mg. The 20 mg and 40 mg tablets are scored. Brand Celexa comes only as tablets.
- Oral solution (generic): 10 mg per 5 mL, which works out to 2 mg per mL. A generic version is still listed with the FDA and sold in the US. Pharmacies may need to order it in.
- Other forms: MedlinePlus also lists a capsule form. If you are prescribed capsules, ask your pharmacist to confirm the strength and whether they can be swapped for tablets.
Outside the US the forms can differ. The UK, for example, sells citalopram oral drops at a different concentration from the US liquid, and the drop count does not match tablet milligrams one to one. If you bring medicine across borders, have a pharmacist check the conversion.
Why the Celexa dosage ceiling is 40 mg
The cap comes from the heart, not from how well the drug works. On August 24, 2011, the FDA issued a Drug Safety Communication. It said citalopram should no longer be used above 40 mg a day because it lengthens the heart’s QT interval in a dose-dependent way. The QT interval is the time the heart’s lower chambers take to recharge between beats. When it stretches too far, it can lead to a dangerous rhythm called torsade de pointes.
In March 2012 the FDA posted an update. The revised FDA recommendations on citalopram and abnormal heart rhythms kept the 40 mg ceiling. They also confirmed the 20 mg cap for higher-risk groups and changed congenital long QT syndrome from “contraindicated” to “not recommended.” They added that citalopram should be stopped in anyone whose corrected QT (QTc) stays above 500 milliseconds.
What the study numbers showed
The FDA based its decision on a study that measured how much the QTc lengthened at each dose, compared with placebo:
| Citalopram dose | Average QTc increase vs placebo | FDA view |
|---|---|---|
| 20 mg/day | 8.5 ms | Acceptable for most adults |
| 40 mg/day | 12.6 ms (estimated) | Upper limit |
| 60 mg/day | 18.5 ms | Clinically significant; no longer recommended |
The FDA also pointed out that doses above 40 mg did not work better for depression. More risk with no added benefit is why the old 60 mg rung was removed. If you want the full heart story, including who needs an ECG and which drugs add to the risk, read our explainer on Celexa and QT prolongation.
Heart warning signs: Get medical help right away if you have a pounding or irregular heartbeat, fainting, sudden dizziness, or shortness of breath while taking citalopram. If symptoms are severe, call 911.
Celexa dosage by population
The right Celexa dosage depends a lot on who is taking the medicine. Here is how the label handles each group.
Adults 18 to 60
Most adults start at 20 mg once a day. Many stay there for good, because 20 mg is an effective dose for many people. If symptoms have not improved enough after a fair trial, a prescriber may go up to 40 mg. The label allows the increase after at least one week. In practice, many clinicians wait longer, because the mood benefits of an SSRI build over several weeks. Our timeline on how long Celexa takes to work explains why patience at one dose often pays off.
Adults over 60
For anyone over 60, the most they should take is 20 mg a day. Older adults clear citalopram more slowly, so blood levels run higher at the same dose. They are also more likely to have heart disease, low potassium or magnesium, or other medicines that affect heart rhythm. SSRIs can also lower blood sodium (hyponatremia) more often in older people. Confusion, headache, unsteadiness or weakness are worth reporting. Caregivers can use the 20 mg cap as a quick safety check when reviewing a pill organizer.
People with liver problems
The liver breaks down citalopram. When it is impaired, the drug builds up. The label caps the dose at 20 mg a day for anyone with hepatic impairment. If you have cirrhosis, hepatitis or a fatty liver diagnosis, make sure whoever prescribes citalopram knows about it.
People with kidney problems
The kidneys play a smaller role. For mild to moderate kidney impairment, the label recommends no dose change. For severe impairment (creatinine clearance below 20 mL/min), there is no information. Prescribers usually go carefully in that group and may check in more often.
CYP2C19 poor metabolizers and inhibitor users
CYP2C19 is a liver enzyme that helps clear citalopram. Some people inherit a slow version of it. They are called “poor metabolizers,” and the trait is more common in some East Asian populations. Usually the only way to know is a pharmacogenetic test, and some health systems now offer one. Certain medicines also slow the enzyme. Cimetidine is the one named on the label, and other CYP2C19 inhibitors (some reflux and antifungal drugs, for example) do the same. Either way, the cap is 20 mg a day. Ask your pharmacist to screen your full medication list, including over-the-counter acid reducers.
Children and teenagers
Citalopram is not FDA-approved for anyone under 18, and the label says its safety and effectiveness in children have not been established. Doctors sometimes prescribe it off-label. That decision belongs to a specialist. Like all antidepressants, Celexa carries a boxed warning about a higher risk of suicidal thoughts and behaviors in children, teens and young adults under 25, especially in the first months and after any dose change.
During pregnancy or breastfeeding
Pregnancy has no separate dose rung on the label. Dosing decisions depend on how severe the depression is and on timing. See our guide to Celexa during pregnancy and breastfeeding before making any plans, and talk with your obstetric provider.
How a typical Celexa dosage titration goes
“Titration” means adjusting a dose a little at a time to find the right one. No two plans are the same, but most citalopram starts follow a pattern like this:
- Screening visit. Your prescriber reviews your heart history, current medicines, liver health and age. If you have heart disease, a slow heart rate, or take other QT-prolonging drugs, they may order an ECG or check your potassium and magnesium first.
- Days 1-7: starting dose. Most adults take 20 mg once a day. Some prescribers start at 10 mg to ease early side effects like nausea, jitteriness or sleep changes, then step up. Citalopram’s half-life is about 35 hours, so blood levels level off after roughly a week of daily doses.
- Weeks 1-2: early check-in. Expect a call, message or visit to ask about side effects and mood. Early side effects often fade within the first couple of weeks. This is also when the boxed warning matters most, so report any new or worsening low mood, agitation or thoughts of self-harm right away.
- Weeks 2-6: hold steady. If you started at 10 mg, you are probably on 20 mg by now. Many people notice better sleep, energy or appetite before their mood lifts. The core antidepressant effect usually takes several weeks.
- Weeks 4-8: decision point. If you have improved only partly at 20 mg and none of the 20 mg cap groups applies to you, your prescriber may raise the dose to 40 mg. The label allows this no sooner than one week after starting. A larger tablet strength is usually prescribed so you are not doubling up on tablets.
- After the increase: reassess. Expect another check-in a few weeks later. If 40 mg still does not help enough, the next step is not 60 mg. It is usually adding therapy, adjusting other treatment, or switching to a different medicine.
- Maintenance. Once you feel well, guidelines generally suggest staying on the effective dose for months, not weeks, to lower the chance of relapse. Your prescriber will set the length of treatment with you.
If you take Celexa for anxiety (an off-label use in the US), the steps are similar, but some prescribers start lower because anxious patients can be sensitive to early jitteriness. Ask your prescriber which pace fits your situation.
How to take citalopram day to day
Morning or evening?
The US label does not name a best time of day. It just says once daily. The NHS guidance on taking citalopram says morning or evening are both fine. The practical rule is to take it at the same time every day and pick the time based on how it affects you:
- If it keeps you awake or makes you feel wired, a morning dose usually makes sense.
- If it makes you drowsy or a little nauseated, an evening dose may let you sleep through those effects.
- If you want to move your dose time, ask your pharmacist how to shift it gradually rather than taking two doses close together.
With or without food
Food does not change how well citalopram is absorbed. You can take it on an empty stomach or with a meal. If nausea is a problem in the first weeks, many people find that taking it with breakfast or dinner helps. Alcohol is a different matter. It can add to drowsiness and may worsen depression, so read our guide to mixing Celexa and alcohol before you drink.
Measuring the liquid correctly
The US oral solution contains 10 mg in every 5 mL. Here is how that translates:
- 10 mg = 5 mL
- 20 mg = 10 mL
- 40 mg = 20 mL
Always use a marked oral syringe or dosing cup from the pharmacy, never a kitchen spoon. Kitchen teaspoons vary a lot in size. Check whether your label is written in milligrams or milliliters, because mixing those up is a common way to give double or half doses. If you are unsure, ask the pharmacist to mark the syringe for you.
Splitting tablets
The 20 mg and 40 mg tablets have a score line. Your prescriber may suggest splitting one to make a smaller step, such as half of a 20 mg tablet for 10 mg. The 10 mg tablet is not scored. Use a pill splitter, and do not split tablets unless you have been told to.
Storage
MedlinePlus advises keeping citalopram in its original, tightly closed container at room temperature, out of reach of children, and not in a steamy bathroom. Take unused medicine to a take-back program instead of flushing it.
What to do if you miss a dose
MedlinePlus and the NHS give the same simple rule:
- Take the missed dose as soon as you remember, if your next dose is still a good way off.
- If it is almost time for your next dose, skip the missed one and go back to your usual schedule.
- Never double up to make up for a missed dose. With citalopram, two doses at once can push you past your safe ceiling and add strain to your heart rhythm.
Because citalopram’s half-life is long, one missed dose rarely causes trouble. Missing several days in a row is different. It can bring on discontinuation symptoms like dizziness, irritability, nausea, anxiety, or “brain zaps” (brief electric-shock feelings). If you often forget, try a phone alarm, a weekly pill box, or linking your dose to a daily habit like brushing your teeth. If you have run out or skipped several days, call your prescriber before restarting.
Taking too much: overdose signs and what to do
Citalopram overdose is more dangerous than many people realize, mainly because of its effects on the heart. Symptoms can be delayed, so someone who seems fine at first may still need hospital monitoring. According to the prescribing information, overdose can cause:
- Seizures, which may be delayed
- Confusion, extreme drowsiness or coma
- Heart rhythm problems, including QT and QRS prolongation, very fast heart rhythms and torsade de pointes
- Serotonin syndrome, especially if other serotonin-boosting drugs were also taken
- Nausea, vomiting, sweating, tremor and a racing heart
The label advises prolonged heart monitoring after an overdose. Learn more about the warning signs of too much serotonin in our article on serotonin syndrome on Celexa.
If someone took too much: Call Poison Control at 1-800-222-1222 (free, 24/7, in the US). If the person has collapsed, had a seizure, is having trouble breathing, or cannot be woken up, call 911 right away. Bring the pill bottle with you. If the overdose may have been on purpose, or you are having thoughts of suicide, call or text 988 to reach the Suicide & Crisis Lifeline.
An accidental extra tablet, such as forgetting you already took today’s dose, is still worth a call to Poison Control. They can tell you whether watching at home is enough based on your dose, age and other medicines.
Switching to or from other antidepressants
Changing antidepressants is a planned move, not a do-it-yourself project. Your prescriber picks one of a few common approaches based on the two drugs involved:
- Direct switch: stop one SSRI and start the other the next day. This is sometimes used between closely related drugs at similar doses.
- Cross-taper: lower the old drug while slowly raising the new one over one to several weeks.
- Taper and washout: fully taper off the first drug and wait before starting the second. This is required for some combinations.
During any overlap, two serotonin-boosting drugs together raise the risk of serotonin syndrome. Agitation, sweating, shivering, muscle twitching, fever or a fast heartbeat during a switch are reasons to call right away.
The MAOI 14-day rule
Monoamine oxidase inhibitors (MAOIs), such as phenelzine, tranylcypromine and selegiline, must never be combined with citalopram. The label requires a gap of at least 14 days in both directions:
- Wait at least 14 days after stopping an MAOI before starting Celexa.
- Wait at least 14 days after stopping Celexa before starting an MAOI.
The same warning covers two hospital drugs that act like MAOIs: the antibiotic linezolid and intravenous methylene blue. If you are admitted to a hospital, tell staff you take citalopram. Pimozide, an older antipsychotic, is also contraindicated with Celexa.
Coming off citalopram
The label advises lowering the dose gradually rather than stopping suddenly whenever possible. A common plan steps down from 40 mg to 20 mg, then to 10 mg, before stopping. The pace is up to your prescriber and depends on how you feel. Our step-by-step guide to Celexa withdrawal and tapering covers timelines and symptoms.
Celexa vs Lexapro dose equivalence
Lexapro (escitalopram) is the “S” mirror-image half of the citalopram molecule, which is the part that does most of the antidepressant work. Because citalopram is a 50/50 mix of the S and R forms, the Psychopharmacology Institute’s comparison notes that escitalopram’s equivalent dose is about half of citalopram’s:
| Celexa (citalopram) | Roughly equals Lexapro (escitalopram) |
|---|---|
| 10 mg | 5 mg |
| 20 mg (usual dose) | 10 mg (usual dose) |
| 40 mg (maximum) | 20 mg (maximum) |
These numbers are a starting point for your prescriber, not a do-it-yourself conversion. Escitalopram also tends to have a smaller QT effect and carries an FDA approval for generalized anxiety disorder that citalopram lacks. For the full comparison, see Celexa vs Lexapro. If you are also weighing sertraline, read our breakdown of Celexa vs Zoloft.
When a dose change might come up
Even when you are stable, some life changes are worth flagging to your prescriber because they can affect your Celexa dosage:
- Turning 60. If you take 40 mg, ask whether your dose should come down to the 20 mg ceiling.
- A new prescription. Drugs that slow CYP2C19 or prolong QT (some antibiotics, antifungals, anti-nausea and heart-rhythm medicines) can change what is safe. Also, mention every new medicine or supplement at the pharmacy counter.
- A new heart or liver diagnosis, or a fainting spell.
- Ongoing vomiting, diarrhea or diuretic use, which can lower potassium and magnesium and make the heart more sensitive to QT effects.
- Side effects that will not ease, such as sexual problems or weight changes. These sometimes improve with a dose adjustment. Bring them up rather than putting up with them in silence.
Any dose change, up or down, is a time to watch your mood closely. Tell your prescriber about worsening depression, restlessness, panic or unusual behavior changes promptly. If you ever have thoughts of harming yourself, call or text 988, or call 911 if you are in immediate danger.
Questions to bring to your prescriber
A short appointment goes further with a list. Write down your answers or bring someone with you.
- What is my starting dose, and why that dose for me?
- Do any of the 20 mg cap groups apply to me, based on my age, liver, genes or medicines?
- Do I need an ECG or blood tests before starting or before going up to 40 mg?
- When will we decide whether this dose is working, and what counts as “working”?
- Which side effects should fade, and which ones mean I should call you?
- Are any of my current prescriptions, over-the-counter drugs or supplements a problem with citalopram?
- Should I take it in the morning or at night?
- If I need liquid, how exactly should I measure my dose?
- What is our plan if 20 mg is not enough, and what if 40 mg is not enough?
- How long should I expect to stay on this medicine, and how would we taper it later?
- Who do I call after hours if my mood gets worse?
Celexa dosage at a glance
The safe Celexa dosage range is narrow: 20 mg for most, 40 mg as a hard ceiling, and 20 mg as the ceiling for several higher-risk groups. Use this summary as a quick check, not as a replacement for your own prescription label.
| Topic | The short version |
|---|---|
| Usual adult start | 20 mg once daily |
| Maximum adult dose | 40 mg once daily, after at least 1 week at 20 mg |
| Maximum over 60, liver impairment, CYP2C19 poor metabolizer, or on cimetidine/CYP2C19 inhibitor | 20 mg once daily |
| Kidney impairment | No change for mild to moderate; no data for severe |
| Under 18 | Not FDA-approved |
| Doses above 40 mg | Not recommended (QT risk, no added benefit) |
| Forms | Tablets 10, 20, 40 mg; generic oral solution 10 mg/5 mL |
| Food | With or without food |
| Time of day | Morning or evening, same time daily |
| Missed dose | Take when remembered; skip if near the next dose; never double |
| Overdose | Poison Control 1-800-222-1222; 911 for collapse, seizure or breathing trouble |
| MAOIs | 14-day gap in both directions |
| Lexapro equivalent | Citalopram 20 mg is roughly escitalopram 10 mg |
| Stopping | Taper gradually with your prescriber |
| Mood crisis | Call or text 988 |
This article is for general information only and is not a substitute for advice from your doctor, pharmacist or other qualified health professional. Do not start, stop or change the dose of any medicine without talking to your prescriber. If you think you are having a medical emergency, call 911. If you are in emotional distress or having thoughts of suicide, call or text 988 in the US.
