Too many blood pressure medicines in patients over 80 could be dangerous if they have low systolic pressure, new European research reveals.

Researchers from several hospitals and universities studied more than 1,100 patients in French and Italian nursing homes, assessing mortality rates along with systolic blood pressure levels and prescribed antihypertensive drugs.

While blood pressure drugs have proven benefits for hypertensive people, “observational studies in frail elderly patients have shown no or even an inverse relationship between BP and morbidity and mortality,” researchers wrote recently in  JAMA Internal Medicine

Instead, those whose systolic pressure fell below 130 and took two or more blood pressure medications had a higher risk of death.

The results provide a “cautionary note” requiring dedicated, controlled interventional studies, they said. The risks of so-called “polypharmacy” have long been suspected as a leading cause of premature death among nursing home residents. A previous study in the American Journal of Geriatric Pharmacotherapy, concluded there was a prevalence of polypharmacy among nursing home residents