At least 40 people are currently hospitalised after being poisoned by diethylene glycol, an industrial chemical toxic to humans that was found in the cough syrup, health authorities said.
Infectious disease specialist Jose Motta said 24 of the 40 patients in hospital were in potentially life-threatening condition.
Chief prosecutor Ana Matilde Gomez said on Wednesday that five people were arrested pending an investigation into their relationship to a company that imported the chemical and then sold it three years ago to the national health service Caja del Seguro Social (CSS), which mixes some of its own medications.
Health Minister Camilo Alleyne said 24 of the medications CSS makes were banned for human consumption. All medication making and mixing was stopped pending a probe of the three-week-old crisis, he said.
Of the 100,000 bottles of cough syrup identified as part of the contaminated lot, 20,000 are still on the street, the newspaper Panama America reported on Thursday.
Opposition parties and some non-partisan groups have called for Alleyne's resignation over the health crisis.

Copyright AFP (Agence France-Presse), 2006