It said that patients who believe they have already taken any Citalopram 40mg tablets by mistake or are experiencing side effects, should seek medical advice immediately.
The MHRA said that pharmacists should stop supplying the batch and contact any patients who may have been dispensed the impacted product – Sertraline 100mg tablets batch number V2500425.
Dr Alison Cave, the MHRA’s chief safety officer, said: “If you have been prescribed Sertraline 100mg tablets and have received batch number V2500425, please check the carton contains the right medication.
“You can find the batch number and expiry date printed on the side of the outer packaging.
“If the blister strips inside the carton are labelled Citalopram 40mg, please contact your pharmacy as soon as possible. If they are labelled Sertraline 100mg, no further action is needed.
“Patients who have accidentally taken Citalopram instead of – or as well as – Sertraline, may experience some heightened serotonergic side effects.
“These can include nausea, headache, sleep changes and mild anxiety.”
In 2019, more than 16.7 million prescriptions of Sertraline were prescribed by GPs in England, according to a study.