Earlier this week, health authorities issued a large-scale recall for one of the most commonly prescribed antidepressants in the UK. More than two million Britons take sertraline to manage depression, anxiety, and other mood disorders like obsessive compulsive disorder (OCD). However, a recall announced by the Medicines and Healthcare products Regulatory Agency (MHRA) on Tuesday revealed that due to a manufacturing error, some boxes of sertraline contained a different drug. Mixing the two could leave patients seriously unwell.
What Happened in the Recall?
The rogue drugs found in some people's boxes, alongside a strip of sertraline 100mg, are citalopram 40mg tablets. Citalopram is another antidepressant commonly prescribed for mental health conditions. Both drugs belong to the class of selective serotonin reuptake inhibitors (SSRIs), which work by boosting levels of serotonin in the brain. However, combining two different SSRIs can trigger a serious condition called serotonin syndrome, which can be fatal. Similarly, abruptly stopping SSRIs can cause debilitating withdrawal symptoms.
How to Identify If Your Sertraline Is Affected
Boxes of 100mg film-coated sertraline tablets with batch number V2500425 and an expiry date of May 2028 are potentially affected. You can find the batch number and expiry date printed on the cardboard carton provided by your pharmacist. The affected batch was first distributed on November 28, 2025, so some boxes may still be unopened. Another sign that your prescription is affected is the presence of a strip of citalopram 40mg inside the box. This blister pack will have 'citalopram 40mg' clearly printed on the foil.
What to Do If Your Sertraline Is Affected
According to MHRA guidance, anyone who finds a rogue strip of the drug should contact their pharmacy immediately. Pharmacists and healthcare professionals involved in dispensing the antidepressant have been advised to contact any patients who may have received the wrong medication and request its return. GPs and clinicians should be informed of the mix-up to discuss treatment review and whether a new prescription is needed for ongoing supply. Patients aged over 65, under 18, or with heart or liver conditions need to be particularly cautious, the MHRA warned. Any suspected adverse reactions should be reported via the MHRA's Yellow Card scheme. Healthcare professionals have been instructed to stop supplying the affected batch and return all remaining stock to suppliers.
Warning Signs of Serotonin Syndrome
Sertraline users are advised to seek medical help immediately if they experience a fast heart rate, nausea, headache, or sleep changes. These symptoms could indicate a life-threatening reaction known as serotonin syndrome, caused by mixing or alternating two types of antidepressants. Official NHS guidance states that symptoms can range from mild to severe and should be treated urgently. Physical symptoms may include hypertension (high blood pressure), tachycardia (heart rate over 100 beats per minute), and hyperthermia (body temperature rising to around 40°C). Other warning signs include dry eyes, unusually active bowel sounds, excessive sweating, tremors, and clonus (involuntary, rhythmic muscle contractions). Patients may also experience muscle and joint stiffness, along with hyperreflexia (exaggerated reflexes). Mental symptoms can include anxiety, agitation, and confusion. In severe cases, the condition can lead to coma.
Risks of Mixing Sertraline and Citalopram
Both sertraline and citalopram are SSRIs used to treat depression, anxiety, and other mood disorders. Alternating or combining SSRIs can be dangerous and even deadly, experts warn. Dr Alison Cave, MHRA chief safety officer, stated: 'Patients who have accidentally taken citalopram instead of – or as well as – sertraline, may experience some heightened serotonergic side effects.' Concerns over mixing SSRIs were highlighted following the high-profile suicide of Thomas Kingston, husband of Lady Gabriella Windsor, in February 2024. Mr Kingston, 45, had been prescribed both sertraline and citalopram for anxiety by a Buckingham Palace doctor. A prevention of future deaths report raised concerns about adequate communication of suicide risks and whether current guidance on persisting with drugs is appropriate when adverse side effects occur. More than 40 similar reports have referenced citalopram or sertraline use, citing failures to alert patients to side effects, breaches of prescribing guidelines, and lack of patient monitoring.
How Did the Mix-Up Occur?
Both drugs were manufactured at the same site, and the error apparently happened during secondary packing of the strips into cardboard packaging. The manufacturing company of the recalled batch received one complaint from an adult patient who reported a headache, where it was found that their prescription wrongly contained a strip of citalopram tablets.
