Four pharmaceutical companies have been raided in Nigeria after a BBC investigation into the role of cough syrup containing codeine in an addiction epidemic.
The firms are in Lagos, Ilorin and Kano, National Agency for Food and Drug Administration and Control said.
Nigeria this week announced a ban on the production and import of the syrup.
The BBC investigation showed the syrup being sold on the black market for young Nigerians to get high.
The probe recorded a number of pharmaceutical employees selling the drug illegally.
Prices of the syrup on the black market have shot up since the ban.
Officials estimate that about three million bottles of codeine syrup are being drunk a day in just two states, Kano and Jigawa.
Excessive consumption of codeine can cause organ failure and schizophrenia.
How were the raids carried out?
"Our inspection and enforcement teams are in the premises of the four pharmaceutical companies that were shown in the [BBC] video," Mrs Mojisola Adeyeye, who heads Nafdac, said.
"Our officials are there putting things on hold, and everything is being documented. When completed, we will prepare our report and then we will take appropriate action.
"If products that are fake or substandard are discovered, such products will be seized and destroyed.
"These companies that were caught, from our records, have a limited amount of codeine, but from what the documentary showed there is indication that the production is more than the quantity approved. So the question can be asked, was there smuggling involved?", Adeyeye said.
The companies concerned have so far made no public comment on the raids.
One of the companies featured in the documentary, Emzor, has released a statement on Facebook denying links to the black market and saying it has launched a full investigation into its current processes.
The member of staff depicted has since been dismissed and reported to the police, the company said.
Bioraj Pharmaceuticals Ltd said it has also suspended an employee and launched an investigation.
What do we know about the ban?
The BBC investigation was carried out by BBC Pidgin and Africa Eye, a new investigation unit.
The probe prompted a swift response from people across the country, including Nigeria's first lady, Mrs Aisha Buhari, who said in an Instagram post she was "deeply saddened" by the rise of the problem.
However, Olajide Oshundun, the Ministry of Health's assistant director of information, said the ban was a result of months of work by a committee, which submitted a report into the widespread abuse of the medication on Tuesday.
While existing stocks could be sold, manufacturers in Nigeria "have been told by federal government not to use codeine in cough syrup", Mr Oshundun said.
"Those that want to import the substance, it is been banned now. It is completely banned," he added.
Ban 'boosts black market'
"Do you know what you have done?" asked Sola Oyekanmi frantically.
"The street price of codeine cough syrup has shot up to 5,000 naira ($14; £10)!" said the Lagos-based media executive with ears on the street.
Just a month ago, drug dealers were selling codeine cough syrup on the street for up to 3,000 naira. The dark addictive syrup has turned to gold.
"You need to understand that the ban on codeine cough syrup is already driving up the price in the black market," explained Oyekanmi.
"I can assure you, by next week, the price will be even higher."
The ban came after BBC Pidgin and Africa Eye's undercover documentary Sweet Sweet Codeine hit Nigerian and African TV screens.
I spent five months on the project, gathering damning evidence that figures in our pharmaceutical industry illegally sell the opioid syrup direct to the black market.
A digital cut-down of our documentary, which showed shocking scenes of addicts in a rehab centre clapped in chains, went viral in West Africa.
The cough syrup was legal in Nigeria.
But it was against the law to sell it to people without a doctor's prescription.
Codeine cough syrup - the scale of the problem
■ Codeine is a pain killer but also an addictive opioid. Taken in excess, it can cause schizophrenia and organ failure
■ Codeine syrup is commonly mixed with soft drinks and often consumed by students
■ The codeine is imported, but the syrup is made in Nigeria by more than 20 pharmaceutical companies
■ Nigeria's drug enforcement agency is fighting this epidemic. In a recent raid, it seized 24,000 bottles of codeine syrup from a single lorry in Katsina
■ Codeine syrup addiction is a problem across Africa, with reports of addiction in Kenya, Ghana, Niger, and Chad
■ In 2016, India banned multiple brands of codeine cough syrup following reports of addiction.
BBC
