Health Minister Dr Fuad Khan said no one should question the quality of drugs being administered to patients in the private and public health sectors without conducting a thorough investigation.

He said each patient responded differently to medication because of several factors and this does not mean the drugs are not good.

Khan was responding to claims by the sister of former prime minister Patrick Manning that medications being brought into the health care system were of low standard.

Dr Petronella Manning-Alleyne made the statement during a news conference at Manning's San Fernando East constituency office on Monday.

She said this country was sourcing drugs from areas of the world where the standards were questionable.

But Khan responded that no one should make such a "blanket statement" without proof.

"You have to first conduct an investigation. It all depends on the state of the patient—his blood sugar level, his blood pressure and other factors. You cannot make a statement like that without proof or an investigation," he said.

Khan said he expected that Manning-Alleyne would have researched her concerns before making the claim.

Manning-Alleyne said the medication given to her brother to thin his blood was being used at private and public health institutions in Trinidad and Tobago, and was "questionable".

She said her brother responded better to drugs sourced in Canada than those brought in from other parts of the world.