Kemsa boss says crisis jeopardises President Uhuru Kenyatta's agenda of universal health coverage.
Mr Wanyonyi says some counties are notorious for delaying payments, citing Baringo which owes Kemsa Sh21 million.
Senators asked Mr Wanyonyi to address the issue of substandard drugs.
Counties owe the Kenya Medical Supplies Authority (Kemsa) Sh2.8 billion as the State agency urged national government intervention to avert a full-blown financial crisis.
Kemsa acting chief executive, Fred Wanyonyi, says the Authority is in a dilemma that endangers healthcare provision in the devolved units.
"We might be unable to support counties due to the huge debts. The Senate should intervene. We have tried to persuade governors to pay the debts which might affect our business model. Universal health care coverage might be affected," Mr Wanyonyi said.
He said the debts have been accrued from the last financial year, adding that the monies owed by counties could jeopardise President Uhuru Kenyatta's ambitious agenda of universal healthcare coverage.
Speaking during the Senate committee on health in Mombasa Friday, Mr Wanyonyi says some counties are notorious for delaying payments, citing Baringo which owes Kemsa Sh21 million.
"We are revising our sale agreement with counties to provide timelines in payments. We have engaged Health Cabinet Secretary Sicily Kariuki who has engaged Treasury. Four counties owe us a lot of money," he said.
Senators asked Mr Wanyonyi to address the issue of substandard drugs in the market and rumours that the Authority stores expired drugs.
Medicinal bhang
Garissa nominated Senator Iman Falhada asked Mr Wanyonyi to consider marijuana use for medicinal purposes.
However, an official from the country's drug regulator did not support the idea.
"It is a debate. We can't encourage use of marijuana because it will be misused in this country," Deputy Registrar, Pharmacy and Poisons Board, Dr Fred Siyoi, said at the forum.
