Citalopram
Is It Right for You?
A complete guide to Citalopram — what it treats, how it works, dosages, side effects, and when a clinician may prescribe it following an online consultation.
What Is Citalopram?
Citalopram is a selective serotonin reuptake inhibitor (SSRI) -- one of the most commonly prescribed classes of antidepressant in the world. It is used primarily to treat depression and a range of anxiety-related conditions, and is widely regarded as one of the better-tolerated SSRIs, with a relatively simple pharmacological profile and fewer drug interactions than some other members of its class.
First introduced in Europe in the 1980s and subsequently approved globally, citalopram became one of the most prescribed antidepressants in the UK throughout the 1990s and 2000s. It remains a commonly used first-line treatment for depression and anxiety, though its use has been subject to dose restrictions since 2011 following regulatory guidance from the MHRA regarding its dose-dependent effect on the QT interval of the heart -- a measure of cardiac electrical activity.
Citalopram is available as tablets and oral drops. It is suitable for adults, and in some cases adolescents with depression under specialist supervision. It is available generically and under the brand name Cipramil.
Citalopram is a prescription-only medication in the UK. A licensed clinician must assess your symptoms, medical history, and current medications before it can be prescribed -- which can now be done quickly and conveniently through a telehealth consultation.
What Conditions Is Citalopram Used For?
Citalopram is licensed for depression and is also used for a range of anxiety conditions, both on-label and off-label:
the primary licensed indication; used for mild to severe depression in adults; effective for both the psychological symptoms (low mood, loss of interest, hopelessness) and physical symptoms (sleep disturbance, fatigue, appetite changes) of depression.
licensed for the treatment of panic disorder with or without agoraphobia; reduces the frequency and severity of panic attacks and associated anticipatory anxiety.
off-label but widely used and evidence-supported for the treatment of persistent, excessive anxiety and worry.
off-label; some evidence of benefit, though other SSRIs (particularly fluoxetine, fluvoxamine, and sertraline) have stronger evidence bases and formal licensing for this indication.
off-label use as an adjunct to psychological therapy to reduce intrusive symptoms, hyperarousal, and co-existing depression.
off-label; used continuously or during the luteal phase of the menstrual cycle to reduce severe mood symptoms and irritability.
off-label; low-dose citalopram has been studied and used to reduce agitation and behavioural disturbance in Alzheimer's dementia, though use must be carefully weighed against cardiac risks in elderly patients
Like all SSRIs, citalopram does not produce immediate relief of depressive or anxiety symptoms. Most patients begin to notice benefit after 2--4 weeks of consistent treatment, with full therapeutic effects typically apparent after 4--8 weeks. Some side effects -- particularly nausea and increased anxiety -- may appear before therapeutic benefits. It is important not to stop treatment prematurely, and to maintain close contact with your clinician during the early weeks of treatment.
How Does Citalopram Work?
Citalopram is a highly selective serotonin reuptake inhibitor (SSRI). Its primary and essentially sole mechanism of action is the inhibition of the serotonin transporter (SERT) -- the protein located on presynaptic neurons that normally removes serotonin from the synaptic cleft and transports it back into the presynaptic cell for reuse or breakdown.
By blocking SERT, citalopram prevents the reabsorption of serotonin, increasing its concentration in the synapse and prolonging its interaction with postsynaptic serotonin receptors. Over time, this sustained enhancement of serotonergic neurotransmission leads to downstream neurobiological adaptations -- including desensitisation of inhibitory presynaptic autoreceptors (which allows even greater serotonin release), changes in receptor density, and neuroplastic changes in key emotional regulation circuits involving the prefrontal cortex, amygdala, and hippocampus. These slower adaptive changes are thought to underlie the delayed but sustained therapeutic effects on mood, anxiety, and emotional resilience.
Compared to older tricyclic antidepressants, citalopram has negligible affinity for muscarinic, histaminergic, dopaminergic, and adrenergic receptors -- the receptor systems responsible for the sedation, dry mouth, constipation, urinary retention, weight gain, and cardiac effects of TCAs. This high selectivity is responsible for citalopram's generally more tolerable side effect profile.
Citalopram is noteworthy for being among the most selective SSRIs for SERT, with very little off-target receptor activity. This contributes to its relatively clean pharmacological profile and its lower propensity for drug interactions compared to SSRIs such as fluoxetine and paroxetine, which are potent inhibitors of CYP enzymes.
However, citalopram has a dose-dependent effect on the cardiac QT interval -- the period of ventricular repolarisation measured on an ECG -- which is thought to be related to blockade of cardiac hERG potassium channels. This is the basis for the MHRA dose restrictions introduced in 2011, which capped the maximum dose at 40 mg daily in adults (20 mg in elderly patients and those with hepatic impairment) and led to the development of escitalopram -- the pharmacologically active S-enantiomer of citalopram -- as a higher-potency, lower-dose alternative.
Dosages & Administration
The correct dose depends on the type and severity of infection, age, weight, and kidney function. Always follow your clinician's instructions. The table below is for general reference only.
Administration Tips
Citalopram can be taken with or without food. Food does not significantly affect its absorption. If nausea occurs in the early weeks, taking it with a meal may help.
Take at the same time each day. Citalopram can be taken in the morning or evening. Morning dosing is often preferred if the medication causes insomnia or vivid dreams. Evening dosing may be preferable if it causes drowsiness. Consistency of timing helps maintain stable blood levels.
Do not exceed the maximum permitted dose. The MHRA has capped citalopram at 40 mg daily for adults under 65 and 20 mg daily for patients aged 65 and over, those with hepatic impairment, and those taking certain interacting medications. Exceeding these limits increases the risk of QT prolongation and potentially fatal cardiac arrhythmias. These limits are not arbitrary and must be observed.
Do not stop citalopram suddenly. Like all SSRIs, citalopram can cause a discontinuation syndrome if stopped abruptly, characterised by dizziness, nausea, "brain zaps" (electric shock-like sensations), irritability, insomnia, and flu-like symptoms. The dose should be tapered gradually under medical supervision when ending treatment.
Allow adequate time to assess effectiveness. A full therapeutic trial of at least 4--8 weeks at an adequate dose is necessary. Do not conclude that citalopram is not working based on the first 1--2 weeks, when side effects are most prominent and therapeutic effects have not yet been established.
Oral drops are available for patients who have difficulty swallowing tablets. Each drop contains 4 mg of citalopram; the drops can be mixed with water, orange juice, or apple juice before taking.
Side Effects of Citalopram
Citalopram is generally well tolerated, with most side effects being mild and transient. The majority occur in the first 1--2 weeks of treatment and resolve as the body adjusts. Serious side effects are uncommon but require prompt attention.
- Nausea (very common in the first 1--2 weeks; usually resolves spontaneously)
- Dry mouth
- Sweating (increased perspiration, particularly at night)
- Headache
- Insomnia or disturbed sleep
- Drowsiness or fatigue
- Tremor
- Diarrhoea or constipation
- Dizziness
- Sexual dysfunction -- reduced libido, delayed ejaculation, anorgasmia (common and may persist)
- Decreased appetite or weight changes
- QT interval prolongation and cardiac arrhythmias -- citalopram causes dose-dependent QT prolongation; risk of serious arrhythmia (Torsades de Pointes) is greatest at high doses, in patients with pre-existing cardiac conditions, electrolyte abnormalities, or those taking other QT-prolonging drugs; the dose restrictions introduced by the MHRA are specifically aimed at minimising this risk
- Serotonin syndrome -- agitation, confusion, rapid heart rate, high temperature, muscle rigidity, and tremor; most likely when combined with other serotonergic drugs; potentially life-threatening and requires immediate emergency treatment
- Suicidal thoughts or worsening depression -- particularly in children, adolescents, and young adults under 25 in the early weeks of treatment or after a dose change; requires close monitoring
- Hyponatraemia (low sodium) -- particularly in elderly patients; presents as confusion, headache, weakness; in severe cases can cause seizures and coma
- Bleeding complications -- SSRIs impair platelet serotonin uptake, increasing bleeding risk particularly when combined with NSAIDs or anticoagulants
- Severe allergic reaction -- rash, facial or throat swelling, difficulty breathing; rare but requires immediate emergency treatment
- Mania or hypomania -- rare; worsening or new onset of elevated mood, impulsivity, or reduced need for sleep; requires immediate review; do not use as monotherapy in bipolar disorder
Citalopram causes a dose-dependent prolongation of the cardiac QT interval -- a measure of the heart's electrical recovery cycle. Prolonged QT can predispose to a potentially fatal heart rhythm called Torsades de Pointes. In 2011, the MHRA issued guidance restricting the maximum dose of citalopram to 40 mg daily in adults under 65 and 20 mg daily in patients aged 65 or over, those with hepatic impairment, and those taking CYP2C19 inhibitors. These restrictions are mandatory and must not be exceeded. An ECG should be considered before starting citalopram in patients with known cardiac disease or other QT risk factors.
Drug Interactions
Citalopram has fewer drug interactions than SSRIs such as fluoxetine and paroxetine due to its relatively limited inhibition of CYP enzymes. However, it has several clinically important interactions, particularly relating to QT prolongation and serotonergic activity. Always disclose all medications to your clinician or pharmacist.
Combining citalopram with MAOIs can cause a potentially fatal serotonin syndrome or hypertensive crisis. Citalopram must not be started within 14 days of stopping an MAOI, and an MAOI must not be started within 14 days of stopping citalopram. This combination is absolutely contraindicated.
Combining citalopram with other QT-prolonging drugs substantially increases the risk of dangerous cardiac arrhythmias. A comprehensive medication review is essential before prescribing citalopram in patients on multiple medications. Many over-the-counter and prescription drugs carry QT-prolonging potential.
Citalopram may affect warfarin metabolism and, through its effects on platelet serotonin, increase bleeding risk. INR should be monitored when starting, stopping, or adjusting citalopram in patients on warfarin.
SSRIs reduce platelet serotonin, impairing aggregation. Combined with NSAIDs or aspirin, the risk of gastrointestinal bleeding is significantly increased. Gastroprotection (e.g. a PPI) should be considered if this combination is necessary.
Although there is no direct dangerous pharmacological interaction, alcohol worsens depression and anxiety and can compound some of citalopram's side effects including sedation and dizziness. Alcohol should be minimised during treatment.
Important Warnings
Citalopram causes clinically significant, dose-dependent QT interval prolongation. The MHRA has mandated maximum doses of 40 mg daily for adults under 65, and 20 mg daily for patients aged 65 and over, those with hepatic impairment, and those taking CYP2C19 inhibitors (including the commonly prescribed omeprazole). These limits must never be exceeded. Patients with pre-existing QT prolongation, cardiac arrhythmias, congenital long QT syndrome, electrolyte abnormalities (low potassium or magnesium), or those taking other QT-prolonging medications should have an ECG before starting citalopram and during treatment.
Antidepressants including citalopram are associated with an increased risk of suicidal thoughts and behaviour in children, adolescents, and young adults under 25, particularly in the first few weeks of treatment or after a dose change. Citalopram is not licensed for use in children under 18 in the UK. Patients in the at-risk age group and their carers should monitor closely for worsening depression, agitation, irritability, or new suicidal thoughts, and seek immediate help if these occur.
Citalopram can trigger serotonin syndrome when combined with other serotonergic medications. This is a potentially life-threatening condition requiring immediate emergency treatment. Patients should be made aware of the symptoms -- agitation, confusion, rapid heart rate, high temperature, muscle rigidity, and tremor -- and seek emergency care immediately if they develop.
SSRIs including citalopram can cause hyponatraemia (low blood sodium levels), particularly in elderly patients, those taking diuretics, or those with low baseline sodium. Symptoms include confusion, headache, weakness, and -- in severe cases -- seizures and coma. Sodium levels should be monitored in high-risk patients when starting citalopram or after a dose increase.
Citalopram should not be used as monotherapy in patients with bipolar disorder, as it can precipitate manic or hypomanic episodes. If depression occurs in the context of bipolar disorder, a mood stabiliser should be in place before an antidepressant is considered. Always disclose any personal or family history of bipolar disorder to your clinician.
Citalopram use during the third trimester of pregnancy is associated with neonatal adaptation syndrome -- transient symptoms in the newborn including jitteriness, feeding difficulties, and respiratory changes. There is also a small risk of persistent pulmonary hypertension of the newborn (PPHN) with third-trimester SSRI use. Citalopram passes into breast milk in amounts that may be clinically significant for the infant compared to some other SSRIs. The risks and benefits must be carefully discussed with your clinician -- untreated depression in pregnancy also carries significant risks for both mother and baby.
Speak to a Clinician About Treatment
Getting advice no longer means sitting in a waiting room. Through The GP Service, you can consult with a licensed clinician in minutes — from home, on your lunch break, or wherever works for you. If treatment is clinically appropriate, your clinician can issue a prescription during the consultation. A consultation does not guarantee a prescription.
The treatment you need, when you need it.
Citalopram FAQs
Yes. A licensed clinician can assess your symptoms, mental health history, cardiac risk factors, and current medications via a telehealth consultation and prescribe citalopram if clinically appropriate. Given the QT prolongation concerns and mandatory dose limits, a thorough assessment is important. Prescriptions are typically sent to your preferred pharmacy the same day.
Most patients begin to notice some initial improvement -- such as better sleep, appetite, or energy levels - within 1-2 weeks, but the full antidepressant and anxiolytic effect typically takes 4-8 weeks to become fully apparent. It is important to persist with treatment for an adequate trial period before drawing conclusions, and to maintain contact with your clinician during this time.
Citalopram does not alter fundamental personality or suppress emotions. Most patients report feeling more like themselves -- better able to function, engage in activities, and experience positive emotions -- rather than feeling numbed or different. Some patients do report emotional blunting or feeling "flat" at higher doses; if this occurs, discuss it with your clinician as a dose reduction or medication switch may help.
For a first episode of depression, treatment is typically recommended for at least 6-12 months after symptoms have resolved, to reduce the risk of relapse. For recurrent depression or anxiety disorders, longer-term treatment may be appropriate. The decision to stop should always be made in discussion with your clinician, with a gradual tapering of the dose planned in advance.
Alcohol and citalopram do not have a direct dangerous pharmacological interaction, but alcohol is a CNS depressant that worsens depression and anxiety and can amplify some side effects of citalopram such as drowsiness and dizziness. Regular or heavy alcohol consumption significantly undermines the benefits of antidepressant treatment. Modest occasional consumption is not absolutely prohibited, but reducing alcohol intake is strongly advisable.
Stopping citalopram abruptly can cause a discontinuation syndrome, characterised by dizziness, nausea, "brain zaps" (electric shock-like sensations in the head), irritability, insomnia, and flu-like feelings. These symptoms are not dangerous but can be very distressing. They typically begin within a day or two of stopping and resolve within 1--2 weeks. To minimise discontinuation symptoms, citalopram should always be tapered gradually under medical guidance -- typically by reducing the dose by 10 mg every 2--4 weeks.