A popular energy drink has been banned in Zambia after tests found it contained the active ingredient in Viagra, according to local authorities.

Natural Power High Energy Drink SX was investigated after a man reported having a six-hour erection, sweating and abnormal heartbeat after consuming it.

Officials in the African nation found some samples of the drink had been spiked with sildenafil and recalled all cans that were on sale.

They warned that consuming the drink 'poses a threat' to the public. Sildenafil has been linked to loss of hearing, vision problems and skin cancer.

Natural Power High Energy Drink SX was investigated and banned by local authorities after it was found to contain Viagra, a statement said

The ban followed a complaint from the country’s medicine regulator, Zambia Medicine Regulatory Authority, in December suggesting the drink was contaminated with sildenafil citrate.

Sildenafil is the active ingredient in Viagra, which can be bought over the counter in the UK but always needs a prescription in Zambia.

The Ndola City Council collected various samples which were forwarded to the Food and Drugs Laboratory for tests.

They said: 'Results from both Zimbabwe and South Africa correlated with those obtained from the Foods and Drugs Laboratory that indicated a positive presence of sildenafil citrate.'

WHAT IS VIAGRA? Viagra was developed in 1998 by accident, after scientists discovered it had benefits for sufferers of erectile dysfunction. Manufactured by Pfizer, the magic blue pills are taken by more than one million men in Britain each year, figures suggest. Most users are in their early to mid 50s, but younger people are starting to take the drugs more often, the pharmaceutical previously said. Until 2013, only the US drug giant had permission to make the pills - costing on average £21.27 for a pack of four. But since its patent expired, rivals have made generic versions containing the same active ingredient, priced at around £1.45 for the same amount of capsules. Celebrities such as Hugh Hefner, the founder of Playboy magazine, and Hollywood actors Ben Affleck and Ashton Kutcher have previously admitted using Viagra. Advertisement

The levels of sildenafil citrate found in the samples ranged from 68.5 mg - 71.3 mg per 250ml of the drink - it is sold in 500ml servings.

Men using Viagra tablets sold over the counter are recommended to take one tablet containing 50 mg of sildenafil.

The statement said: 'However, the raw material samples tested negative therefore confirming the alleged adulteration.

'The Ndola City Council has also suspended the production of Natural Power SX Energy Drink until remedial measures are put in place to the satisfaction of all the mentioned regulatory authorities.'

The manufacturer, Revin Zambia Ltd, could not immediately be reached for comment on the ban.

The company also export the drink, characterized by it's muscley man on the front, to other African countries such as Uganda and Malawi.

Natural Power Energy Drink SX is very popular among Zambian people, sold mostly in supermarkets and bars.

Sildenafil, used to treat erectile dysfunction in men, 'should only be taken upon recommendation by a medical doctor', the council said.

'The team of medical experts from the stated relevant authorities have highlighted many adverse side effects if not being administered with medical prescription, thus the drink Natural Power SX possess a threat to members of the public.'

Sildenafil has been linked to loss of hearing, vision problems and skin cancer.

As many as one in ten people, side effects include dizzines, skin flushes and blurred eyesight.