The NHS has issued a warning to individuals taking one of the UK’s most frequently prescribed antidepressants regarding its potential side effects. Patients experiencing ongoing issues should consult with a doctor.

Citalopram is a selective serotonin reuptake inhibitor (SSRI) antidepressant. As noted on the NHS website, the medication appears to aid many individuals in recovering from depression and helps others who deal with panic attacks.

Available only via prescription, citalopram is among the UK’s top-prescribed antidepressants. Typically, it’s taken once daily either as a tablet or liquid drops, which are mixed with water for consumption.

While you can take it at any time, consistent timing each day is recommended. Most doctors advise continuing antidepressants for six months to a year since discontinuing earlier might lead to a relapse of depression.

Full effectiveness of citalopram usually occurs in four to six weeks, though improvements can often be felt after one to two weeks of use.

The NHS notes, “Like all medicines, citalopram can cause side effects in some people, though many experience none. Several common side effects will gradually subside as your body adjusts to the medication.”

Common side effects include:

• being unable to sleep
• dry mouth
• sweating a lot
• feeling sleepy, tired or weak
• headaches
• nausea

There are some more serious side effects, such as gaining or losing weight without trying, signs of increased bleeding (changes in your periods, bleeding from the gums, blood in urine and poo) and strong feelings of happiness, enthusiasm or excitement, or feeling restless where you cannot sit or stand still.

The NHS website also warns that there could be some sexual side effects when people first start taking citalopram. The health service suggests that these may include:

• painful erections and problems getting an erection and ejaculating
• some vaginal bleeding
• not reaching orgasm the same way as before
• a lower sex drive

In an alert to anyone taking the medication, the NHS says: “Sexual side effects usually stop after the first couple of weeks. Sometimes, however, they can be long-lasting and may not get better even after you stop taking the medicine. If this happens and it’s a problem for you, go back to your doctor to see if there’s another treatment you can try.”

Who can and cannot take citalopram?

Most adults and children aged 12 years and over can take citalopram. If you have diabetes, citalopram can make it more difficult to keep your blood sugar stable, so this should be discussed with a doctor and monitored closely.

People who have other kinds of conditions may also find themselves unsuitable to take citalopram, such as anyone who has a heart problem, as citalopram can make your heart beat faster or cause an irregular heartbeat.

Is there anything I should avoid?

The NHS website states that there are no foods or drinks you need to avoid while taking citalopram. However, it does mention not to take the herbal supplement St John’s wort while you’re taking citalopram as “it will increase your risk of side effects”.

Combining these two can lead to an excess of serotonin in the brain, a condition known as serotonin syndrome that can be life-threatening.