The number of cardiac patients who died after being administered a bad drug at a state-run hospital in this Pakistani city rose to 28 today even as authorities sealed the factory where the medicines were manufactured.

The Punjab Institute of Cardiology (PIC) provided the drug – cardiovestin – free of cost to scores of patients.

About 100 patients who took the drug were admitted to hospitals and half of them were in a serious condition, officials said.

Officials said reports had put the initial death toll at 25 and three more persons had died subsequently.

The PIC has stopped giving life-saving medicines to some 8,000 patients registered with it, they said.

"The Health Department today raided Mega Pharma for manufacturing the suspected drug and sealed its factory," Health Department spokesman Ikhlaq Ahmed told PTI.

The team of doctors investigating the deaths had mentioned a reaction to cardiovestin as a possible reason for the deaths in a preliminary report, Ahmed said.

A 15-member panel of senior doctors headed by Allama Iqbal Medical College principal Javed Akram is probing the deaths.

Akram said a combination of four other drugs had been linked to the deaths after an initial probe and cardiac patients had been advised not to use these medicines.

He said denying some 8,000 poor patients of free medicines would make them more vulnerable.