CARACAS (Reuters) - The death toll following a mass drug overdose incident in a Venezuelan jail last month has jumped to 48 from 13, the government said on Thursday.

Prisoners at the David Viloria penitentiary center in the western state of Lara had broken into an infirmary ward on Nov. 24, according to officials, after a protest for better living conditions spiraled out of control.

A total of 148 inmates were intoxicated after ingesting products that included antibiotics and fever-relievers, the government said in its statement.

The incident has thrown the spotlight back onto the South American country's notoriously turbulent prisons, where riots, weapons and drugs are widespread. A bloody riot at that same prison last year claimed over 50 lives.

There has been no independent confirmation of what happened during the incident, and rights groups have cast doubts over the official version.

The Venezuelan Observatory of Prisons has been collecting testimonies from relatives of prisoners, who say the inmates were poisoned by water and food brought in from outside.

(Reporting by Alexandra Ulmer; Editing by Andrew Cawthorne and Bernadette Baum)