The makers of Nurofen Plus recalled the tablets tonight and confirmed sabotage was suspected in packets of the painkillers.
Five reported cases of other manufacturers’ medicines were discovered in boxes of Nurofen Plus with a spokesman for manufacturer Reckitt Benckiser (UK) Ltd saying: “Sabotage is suspected and we are working with the police on a formal investigation to find the person or persons responsible.
“Distribution of Nurofen Plus has been halted at this time.”
Dr Aomesh Bhatt, Medical Director for Nurofen Plus, added: “We are taking this matter extremely seriously and have decided to recall all packs of Nurofen Plus as the most prudent course of action in the current circumstances.
“We’re asking consumers to return any packs of Nurofen Plus to a pharmacy. No other Nurofen products are affected or being recalled.”
Investigators began trying to establish how some packs of Nurofen Plus came to contain strips of a potentially harmful anti-psychotic drug after yesterday’s safety alert.
Consumers were warned to check their supplies after the Medicines and Healthcare products Regulatory Agency (MHRA) issued a warning that some packs contained Seroquel XL 50mg.
Three packs of Nurofen Plus were found to contain blister packs of the anti-psychotic medicine.
They were bought in Victoria, Bromley and Beckenham, south London.
In each pack, the end two capsules of Seroquel XL had been cut off.
But today, two more packets were found.
One contained Seroquel XL 50mg tablets and the other contained the Pfizer product Neurontin 100mg capsules.
The Reckitt Benckiser spokesman added: “The safety of our consumers is paramount. Even though there have been no serious health consequences to any consumer, we will not take any risk regarding the quality or safety of our products.
“This decision has been taken in full consultation with the Medicines and Healthcare products Regulatory Agency as a precautionary measure.
“Consumers are advised to return any packs of Nurofen Plus to any pharmacy where a refund will be provided.
“Pharmacists are advised to return stock to their wholesaler from where it will be collected.”
Ian Holloway, of the MHRA’s Defective Medicines Report Centre (DMRC), said: “People should check to see if they have any packets of Nurofen Plus.
“If you do, return them to your nearest pharmacy.”