Two-for-one offers on painkillers have been criticised by the UK's medicines watchdog.
All supermarkets have now agreed not to offer deals on medications
The Medicines and Healthcare products Regulatory Agency (MHRA) has upheld two separate complaints against Tesco and Superdrug.
The MHRA said the offers went against the aim of restrictions on pack sizes designed to reduce the risk of suicides.
Both companies have said they will not run similar promotions again.
Boots the Chemist submitted a complaint to the MHRA in April this year about Tesco's 'two for £1.38' offer on eight-tablet packs of Nurofen tablets.
The MHRA also carried out its own investigation in May into Superdrug's offer of two packs of its own brand Ibuprofen.
It was selling two 16 capsule packs of 200mg Liquid Capsules for £3.
The MHRA said it had taken action against sales of analgesics because they could lead to consumers buying medicines they did not need and storing them at home.
It said this was out of line with restrictions on pack sizes, introduced by the government in 1998, which were aimed at reducing the amount of potentially dangerous medication people had access to and therefore the risk of impulsive suicides or children being accidentally poisoned.
A British Medical Journal study showed that since these restrictions were introduced, deaths from suicide in the UK have fallen by around 22%.
After being informed of the MHRA's concerns, Superdrug immediately withdrew its promotional offers and confirmed it would not run similar promotions in the future.
Tesco also confirmed it would not offer customers such deals in the future.
Jeremy Mean, MHRA Policy Group Manager, said Tesco and Superdrug were now acting responsibly, along with other companies such as Boots, Asda and Netto.
He added: "Promotions that lead to the unnecessary purchase of medicines and which undermine the intention of the pack size restrictions that have been brought in for the protection of public safety are not acceptable.
"When it comes to safety issues, the MHRA will not tolerate irresponsible promotion that undermines public health."
A spokeswoman for Superdrug told the BBC News website: "On being informed of MHRA's concerns about the promotion of analgesic-containing products, we responded immediately and withdrew all promotional offers.
"We will adhere to MHRA's guidelines and do not plan any volume-based promotions on analgesic-containing medicines in the future."
A Tesco spokesman said: "We are a responsible retailer of medicines and so, whilst we disagree with the basis of the MHRA's concerns over our Nurofen promotion, we have no current plans to run this type of promotion again.
"Customers who took up the promotion were purchasing 16 tablets at a reduced price, which clearly fell within both the pack-size restriction introduced by government, and the spirit and intention of this legislation."
Lynsey Balmer, head of professional ethics at the Royal Pharmaceutical Society said: "Medicines are not ordinary items of commerce.
"We would be concerned about any promotional campaigns that encourage members of the public to purchase excessive quantities of medicines.
"Pharmacists have a professional responsibility to ensure that promotions emphasise the special nature of medicines and do not encourage inappropriate or excessive consumption of them."