The screws have been tightened further on the illegal sale of codeine.
Those who engage in the unlawful sale or import of codeine-based cough mixtures now face harsher penalties, in the first change to this legislation in nearly 30 years.
Offenders can now be fined up to $50,000 on each charge - five times the previous $10,000 limit - and/or jailed for up to two years.
The stiffer penalties took effect on Nov 1, revealed the Health Sciences Authority (HSA) in response to queries from The Straits Times.
It is the first time since 1987 that the prescribed sentence for such codeine-related offences has been revised. In the past, anyone caught illegally importing or selling codeine cough mixtures could be fined up to $10,000 and/or jailed for up to two years, under the Poisons Act.
The revision comes as the regulatory control of pharmaceutical products - which include codeine cough syrup - is transferred to the Health Products Act, from the Medicines Act and Poisons Act.
It is part of a broader effort, since 2007, to streamline the regulations for health products, which also include medical devices and cosmetics, under a single Act.
Dr Dorothy Toh, acting group director of HSA's health products regulation group, said: "With the higher penalties... we hope that a strong deterrent message is sent to those who are thinking of profiting from the illegal sale or supply of such products."
So far, no one has been charged under the revised penalties.
The latest development underlines the longstanding problem of codeine addiction and illegal sales here. Just three weeks ago, a pharmacist who worked at Bukit Timah Plaza was jailed for eight months and three weeks for unlawfully selling about 20,400 bottles of codeine cough syrup over a decade.
Doctors commonly prescribe this medicine for dry coughs, as codeine is a potent cough suppressant.
Today, there are 30 products registered in Singapore that contain codeine as an active ingredient. Of these, 24 are for treating coughs, and most come in liquid form.
Strict rules govern their sale. For instance, codeine-based cough syrup can be sold or supplied only by doctors and registered pharmacists. No more than 240ml of codeine cough mixture can be sold to a person at any one time, nor can it be dispensed to the same person within four days of the last sale.
Still, the black market has persisted, even as the authorities continue to take action to choke the illegal supply pipeline. HSA, for instance, works with the Central Narcotics Bureau, Immigration and Checkpoints Authority and Singapore Police Force to carry out targeted operations, said Dr Toh.
From 2011 to 2015, about 3,800 litres of codeine cough mixture with a street value of $1.3 million were seized, according to HSA. Forty people were prosecuted for its illegal sale during this period.
Ultimately, demand drives the supply, said an HSA spokesman.
"As long as there is demand for such products, there will be unscrupulous persons looking to make a quick profit," she added.