Image caption Only packs of Nurofen Plus were affected

A man has been arrested by police investigating how some packets of Nurofen Plus came to contain antipsychotic drugs.

The 30-year-old is from Bromley in south London.

In August, the Medicines and Healthcare products Regulatory Agency (MHRA) issued a safety alert after packs were found to contain Seroquel XL 50mg.

Four packs were found to contain the drug. They were bought in Victoria, Bromley and Beckenham in south London.

Another tampered pack, containing a prescription medicine for epilepsy, was uncovered in Northern Ireland.

AFFECTED PACKS Batch 13JJ - Expiry date 03/2014. Product licence no - 00327/0082. First distributed - 30 April 2011

- Expiry date 03/2014. Product licence no - 00327/0082. First distributed - 30 April 2011 Batch 57JJ - Expiry date - 05/2014. Product licence no - 00063/0376. First distributed - 21 June 2011

- Expiry date - 05/2014. Product licence no - 00063/0376. First distributed - 21 June 2011 Batch 49JJ - Expiry date - 05/2014. Product licence no - 00063/0376. First distributed - 1 July 2011

Seroquel XL is a prescription-only anti-psychotic drug used to treat several disorders including schizophrenia, mania and bipolar depression.

Most people who took one Seroquel tablet would experience sleepiness, but those on sedatives could have felt stronger effects.

Nurofen Plus is for pain relief and contains codeine and ibuprofen.