How citalopram works
Citalopram interferes with brain metabolism, more specifically with the metabolism of the nerve messenger (neurotransmitter) serotonin. Neurotransmitters transmit nerve signals between brain cells by being secreted by one cell and then binding to specific docking sites (receptors) on the next cell. The neurotransmitters are then reabsorbed into the cell of origin and thus inactivated.
Experts suspect that an insufficient amount of released serotonin plays a role in the development of depressive symptoms. This is where citalopram and other selective serotonin reuptake inhibitors (SSRIs) come in: They selectively inhibit the reuptake of serotonin into the cells from which it was released. This allows the neurotransmitter to exert its mood-lifting and anxiety-reducing effects for longer.
Even if the correlations are not yet fully understood, citalopram can often be used to get depression under control quite well. It should be noted, however, that the effect only sets in two to six weeks after the start of treatment, as the processes described do not occur immediately.
Absorption, breakdown and excretion
Citalopram is well absorbed in the gastrointestinal tract after ingestion by mouth (per oral). After absorption into the bloodstream, the drug crosses the blood-brain barrier to block reuptake of released serotonin in the central nervous system.
The breakdown of citalopram occurs mainly in the liver with the involvement of various CYP enzymes. After approximately 36 hours, half of the active substance is excreted from the body again (half-life).
When is citalopram used?
Outside these indications approved by the drug authorities, citalopram is also used for other mental illnesses (“off-label use”).
The duration of treatment depends on the success of recovery and is always determined by the treating physician. It is often one to several years.
How citalopram is used
As a rule, citalopram is taken as a film-coated tablet once a day (in the morning or evening), irrespective of meals. Because the active ingredient has a long half-life, a once-daily dose is sufficient. Rarely, the active ingredient is administered as an infusion solution (in patients undergoing inpatient treatment).
Persons over 65 years of age should receive only half the dose of the amount normally used.
If long-term treatment with citalopram is to be discontinued, experts recommend reducing the dose of the active substance slowly and gradually (“tapering”) – abrupt discontinuation often results in discontinuation symptoms such as malaise, nausea and headaches. In many cases, tapering the therapy can prevent such symptoms. It is planned and accompanied by the doctor.
What are the side effects of citalopram?
Especially in the first two weeks of therapy, the following side effects are observed:
Patients prone to suicidal ideation should be closely monitored during the first two to four weeks of treatment until the antidepressant effects of citalopram kick in.
Other side effects that occur frequently (in one to ten percent of those treated) or very frequently (in more than ten percent of those treated) are:
- weight loss and decreased appetite
- anxiety, nervousness, confusion
Occasionally (in 0.1 to one percent of those treated), citalopram causes weight gain and increased appetite.
Since the active ingredient acts directly in the central nervous system, many other side effects are known in addition, but of secondary importance. This list reflects only the most important side effects of citalopram.
What should be considered when taking citalopram?
Contraindications
Citalopram must not be used in:
- hypersensitivity to the active substance or to any of the other ingredients of the drug
- concomitant use of monoamine oxidase inhibitors (MAO inhibitors – used to treat depression and Parkinson’s disease)
- concomitant use of linezolid (antibiotic), unless close monitoring of blood pressure can be ensured
- concomitant use of pimozide (antipsychotic)
- congenital or acquired long-QT syndrome (prolongation of the QT interval in the heart, visible in the ECG)
Drug Interactions
Simultaneous use of citalopram and alcohol should be avoided because sensitivity to alcohol is increased during therapy. Patients taking citalopram report severe hangover experiences and severe malaise even after consuming common amounts of alcohol.
Likewise, medications that also affect the serotonin balance should be avoided during therapy. Some drugs against migraine (triptans), opioid painkillers (tramadol, fentanyl) as well as serotonin precursors as mild sleep aids or to lift the mood (tryptophan, 5-HTP) should only be used after consultation with the doctor or pharmacist.
Common medications that cause QT time prolongation include certain antibiotics (azithromycin, erythromycin, ciprofloxacin, clarithromycin, cotrimoxazole), asthma medications (salbutamol, terbutaline), antifungal medications (fluconazole, ketoconazole), and cold medications (ephedrine, pseudoephedrine, phenylephrine, phenylpropanolamine).
If you notice yourself irregular heartbeats or similar side effects, inform a doctor!
Citalopram may increase the anticoagulant effects of anticoagulants (warfarin, phenprocoumon, direct oral anticoagulants, heparins), antiplatelet agents (ASA, clopidogrel, prasugrel, ticagrelor, NSAIDs), and rheologics (pentoxifylline, naftidrofuryl, dipyridamole).
Because citalopram can interact with many other agents, you should tell the doctor and pharmacist about all other medications you are using. This also applies to over-the-counter and herbal preparations.
Age restriction
Pregnancy and lactation
During pregnancy and lactation, citalopram should be taken only if absolutely necessary and after a careful risk-benefit assessment. If treatment is indicated or if stable therapy is to be continued, the drug is a first-line agent. Breastfeeding is generally acceptable with citalopram.
How to obtain medications with the active ingredient citalopra
Medicines containing citalopram are available only on prescription in Germany, Austria, and Switzerland.
How long has citalopram been known for?
Citalopram was developed in the course of the search for a new anticonvulsant (antiepileptic). When it was discovered that the active ingredient exerted an antidepressant effect rather than an antiepileptic effect, it was patented in this indication in 1989.
The patent for citalopram expired in 2003. Since then, numerous generics containing the active ingredient have come onto the market.
