LUSAKA (Reuters) - Zambia banned an energy drink on Wednesday after it was shown to have been adulterated with the male sex booster Viagra, according to authorities in Ndola, the city of manufacture.

The prohibition followed a complaint from Zambia’s medicine regulator in December suggesting that the Power Natural High Energy Drink SX had been spiked with Viagra.

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

The drink is also exported to African countries such as Uganda, Malawi and Zimbabwe, the manufacturer said last year.

The Uganda National Drug Authority said in a letter dated Dec. 28, 2018 that it made similar findings after a customer complained of constant sweating and a nearly six-hour erection.

Zambia had ordered the manufacturer to withdraw the drink after tests showed it contained Sildenafil Citrata whose brand name is Viagra, a Ndola local authority statement said.

Sildenafil is an active ingredient in oral therapy in erectile dysfunction in men and should only be available on prescription, the statement 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,” it said.

Zambia has also suspended the production of the drink until remedial measures are put in place to ensure that it is not adulterated, the statement said.

In January, Malawi banned the drink following tests conducted at its drug quality control laboratory after safety concerns were raised in Zambia and Uganda.

Natural Power Energy Drink SX is very popular among Zambian men and is sold in 500 ml plastic cans, mostly in supermarkets and bars.