DAKAR(Reuters) - The United Nations on Wednesday flagged harmful new drug concoctions, named kush, Khadafi, and Monkey Tail, as posing particular health risks across Africa because of their varying and often unknown ingredients.

The drugs are believed to contain dangerous mixtures of pharmaceuticals, alcohol and solvents, the UN Office on Drugs and Crime (UNODC) said in its annual World Drug Report.

Reports this week have documented the problems associated with drug abuse.

Sierra Leone in April declared a national emergency over the rising use of kush, a synthetic mixture of marijuana, tentanyl and tramadol.

Ivory Coast, in response to the high use of Khadafi - a mixture of tramadol and energising alcoholic beverages - last year banned the import and export of such beverages.

Monkey Tail is mostly used in Nigeria, according to the UNODC, which said it comprises homemade gin and cannabis seeds, leaves, stems and roots.

UNODC said countries must boost their scientific testing capacities to help law enforcement and health agencies to mitigate the threat of emerging drugs.

While cannabis remains the most sourced, trafficked and used drug on the continent, it cited the impact of an increase in the trafficking of other substances, such as cocaine from Latin America and heroin and methamphetamine from South-West Asia, en route to Europe and elsewhere.

"The local drug markets in Africa are rapidly diversifying, shifting from a predominance of domestically sourced cannabis to a multitude of transiting drugs," UNODC said.

"This diversification is exacerbating existing health challenges, particularly as the availability of drug treatment services are limited in West Africa."

It also noted that over 90% of global tramadol seizures occurred in Africa in the last five years.

(Reporting by Portia Crowe; Editing by Barbara Lewis)