Government officials seized all Tyno stock and the factory where the cough syrup is manufactured was sealed, The Express News reported.
The deaths occurred in low-income neighborhoods of Shahdra, a Lahore suburb, between Friday and Sunday, and most of the victims were identified as drug addicts who took the syrup for non-medicinal purposes, local police station chief Atif Zulfiqar said.
"At least 13 people, mostly drug addicts, have died after taking the toxic syrup," Zulfiqar told Geo News.
Three pharmacies were shut down and their owners arrested, officials said.
Khawaja Salman Rafiq of Punjab's Health Ministry said the province's chief minister, Shahbaz Sharif, ordered an inquiry and directed that a report be submitted to him within three days.
Doctors at Lahore's Mayo Hospital said 20 victims were admitted after ingesting the syrup and most had a history of addiction. Of eight still hospitalized, two were in critical condition.