The verdict capped years of investigation and a convulsion of shock at the many deaths in this small Central American nation.
Officials say 400 people died when they drank the adulterated cough syrup, which had been mixed and distributed by the national health agency using an ingredient supplied by a private company, Medicom.
Some Panamanian organizations believe as many as 10,000 people may have died from the medicine.
Medicom had bought the ingredient, labeled “TD glycerin”, from a Spanish pharmaceutical firm, Rasfer International, which had purchased it from a Chinese group, CNSC Fortune Way Company, which had sourced it from the Taixing Glycerine Factory.
In reality, the ingredient contained high amounts of diethylene glycol, a poisonous, practically odorless liquid which has a sweetish taste. The compound can be used as a solvent, in brake fluid, or in heating fuel, and is often found in automobile antifreeze.
The scandal triggered investigations in Panama, Spain and China.
In Panama, 26 people were charged over the matter, with 11 of them prosecuted.
On Friday, the legal representative of Medicom in Panama, Angel Ariel de la Cruz Soto, was sentenced to five years in prison and fined $6,000.
The four other people sentenced received terms of one year. Six people were acquitted.