Media playback is unsupported on your device Media caption Turing Pharmaceuticals boss Martin Shkreli had previously defended the price raise

A US drug company that faced a backlash after raising the price of a drug used by Aids patients by over 5,000% has said it will lower the price.

Martin Shkreli, the head of Turing Pharmaceuticals, told US media he would drop the price following the outcry, but did not say by how much.

Turing Pharmaceuticals acquired the rights to Daraprim in August.

It then raised the cost of the drug, which treats a parasitic infection, from $13.50 (£8.70) to $750.

Amid criticism from medical groups - one called the cost "unjustifiable" - Mr Shkreli on Monday defended the increase, saying the profits would help research new treatments.

Media playback is unsupported on your device Media caption US presidential candidate Hillary Clinton says she will make pharmaceutical companies put more money into research if she is elected

He accused critics of not understanding the pharmaceutical industry.

But he has now told ABC News: "We've agreed to lower the price on Daraprim to a point that is more affordable and is able to allow the company to make a profit, but a very small profit."

Earlier in the day, PhRMA, the pharmaceutical industry's main lobbying group, tweeted that Turing "does not represent the values of PhRMA member companies".

Setting the price: Michelle Roberts, BBC health editor

Media playback is unsupported on your device Media caption How much does it cost to develop a drug?

Agreeing a price for any drug is a tricky business.

In the UK, the National Health Service is the main buyer and prices are set through a voluntary scheme between manufacturers and the government, trying to strike the right balance of serving patients and generating money to keep the drug pipeline going. Profits are capped to stop prices creeping too high.

In the US, the buyers are private insurance companies as well as the government through the Medicare and Medicaid system. It's a market and prices can go up and down, depending on what people are willing to pay.

In recent years, pharmaceutical research and development has slowed and companies have to think carefully about what they invest in. Blockbusters such as Viagra pull in money, but orphan drugs for rare diseases can be less attractive. Not many patients use them, and so turning a profit may be difficult.

What's a fair price for a drug? Read more