Gary Robson, 59, said his mum Gloria, 81, had a fatal brain bleed
after taking Nolotil.
The anti-inflammatory was given to her by Spanish medics for back pain — but has been banned in the UK, US, Australia and most of Europe.
Doctors warn it can have a “toxic effect”, causing blood disorders.
Builder Gary, of Romford, Essex, urged Brits to challenge doctors who prescribe it.
He said: “They dish out Nolotil like Anadin but there’s no warning on the pack.” He believes his dad Alan, 82, was taking the drug before he died in Spain last year.
William Smith, 66, and Mary Ward, 59, also died after taking Nolotil — a brand name for metamizole.
Spain’s General Directorate of Pharmacy declined to comment.