The prescription-only medicine is taken by 11 million people across Britain to reduce the risk of heart disease. The Medicines and Healthcare products Regulatory Agency (MHRA) is contacting all pharmacies across the country to alert them to withdraw the fake boxes of Lipitor, the world's best-selling medicine.
It is only the third time in a decade imitation medicine has entered the legitimate drug supply chain.
Custom officers confirmed they had intercepted fake pills in Rotterdam in May, leading to the MHRA recalling a batch of 120,000 Lipitor 20mg tablets bearing the number 004405K1, found to contain another statin that is not available in Britain.
It is not known how many patients may have been taking the false medication, but Nino Ahmed, head of intelligence at the MHRA, said: "Our testing of the counterfeit product indicates there is no immediate risk to patients. If patients have any concerns about side-effects they should discuss them with their doctor."
Pfizer, which manufactures the drug that brings in £12bn annually, urged the Government and European authorities to take more action to stop medicine fraud.
Kate Lloyd, medical director of Pfizer UK, said: "Patient safety is our top concern and we are seriously alarmed at the discovery of counterfeit medicine in the UK. Patient safety is at risk."