Citalopram: uses, side effects and heart-rhythm cautions

Citalopram is a selective serotonin reuptake inhibitor, a type of antidepressant. The NHS lists two uses: depression and panic disorder. It increases serotonin in the brain, a chemical linked to mood, and may reduce stress and negative thoughts as it does so.

The NHS does not recommend it for under-18s.

This is the most distinctive part of the citalopram guidance. The NHS says the medicine is not suitable for people who have had a heart attack or who have a heart rhythm problem. Diabetes, epilepsy, liver or kidney disease, glaucoma and a past episode of mania also call for discussion with the prescriber.

The serious effects the NHS lists include torsades de pointes, described as a rare, life-threatening heart rhythm problem. Fainting or a very fast, irregular heartbeat while taking citalopram should be treated as urgent.

Tablets are taken once a day, in the morning or evening, and swallowed whole. Oral drops are the alternative; the NHS says they are mixed into water or juice. Food does not matter.

A missed dose should be taken when you remember unless the next dose is nearly due. Do not take two doses together to make up.

The NHS says improvement can take a few weeks and the course usually lasts at least 6 months. That is a long commitment, so it helps to agree a review point with your prescriber, keep a note of how your mood and sleep are changing, and mention any new symptom rather than waiting for the next appointment.

The NHS says most side effects ease within about two weeks, although some people find they last longer. Speak to a pharmacist or prescriber if they bother you.

• Common: headaches, nausea and vomiting, sweating, dry mouth, diarrhoea or constipation, trouble sleeping, palpitations and sexual problems.

• Do not drive or use machinery if you feel dizzy or drowsy.

• Ask for urgent help through NHS 111 for serotonin syndrome, internal bleeding such as blood in vomit, urine or stools, torsades de pointes, an allergic reaction, or thoughts of harming yourself.

The NHS names several medicines to avoid or check first: sumatriptan, tramadol, ibuprofen and warfarin, as well as other antidepressants and blood thinners. St John's wort should not be combined with it.

It is best not to drink alcohol, which can increase side effects.

The NHS says citalopram can be used during pregnancy if needed and while breastfeeding, but talk to your doctor first so the benefits and risks can be weighed for you.

Do not stop suddenly. Your doctor will lower the dose gradually over a few weeks to avoid withdrawal symptoms. Suspected side effects can be reported to the MHRA Yellow Card scheme.