Patients taking one of the two most common blood pressure drugs are 60% more likely to kill themselves than those on the alternative, a study has found.
Up to 14 million adults are eligible for the medication after NICE lowered thresholds this year.
The increased risk was found in those taking ARBs, compared with those on ACE inhibitors.
Both drugs work by relaxing blood vessels, and are the standard treatments for patients under 55.
Common types of ARB include candesartan, irbesartan, losartan, valsartan and olmesartan.
Until now it was thought the only side effects of ARBs – angiotensin-2 receptor blockers – were dizziness, headaches and flu-like symptoms.
But Tony Antoniou of St Michael’s Hospital in Toronto, Canada, said: “Our findings suggest a possible increased risk of suicide associated with the use of ARBs compared with ACE inhibitors among adults aged 66 and older.
“Preferential use of ACEIs over ARBs should be considered, particularly in patients with severe mental health illness.”
The study looked at 964 older people who took their lives between 1995 and 2015, and 3,900 controls.
The Medicines and Healthcare Products Regulatory Agency said: “ARBs are a safe and effective treatment.
“We will carefully evaluate the study.
“Patients are advised not to stop taking their medication.”
While an increase of 60% compared to the other drug may seem high, five people out of the 964 studied took their lives.
This is a small sample size that may not suggest a definite causal trend.