Nine people were hospitalized with serious skin reactions after taking unregistered medicines claimed to boost energy and improve alertness, the Health Sciences Authority (HSA) reported on March 10, 2025.
Between February 2024 and February 2025, seven men and two women aged 18 to 57 developed life-threatening skin conditions after consuming modafinil or armodafinil without prescription.
These cases follow three similar incidents reported in November 2023.
The patients obtained these medicines from street peddlers in Geylang or from friends. They took them without medical supervision to improve alertness or boost energy, according to HSA.
Six of the nine patients developed Stevens-Johnson syndrome (SJS), a life-threatening condition causing blistering and severe peeling of skin and mucous membranes.
One man in his 40s suffered from severe oral ulcers that prevented him from eating or speaking for several days.
Three others developed toxic epidermal necrolysis (TEN), a more severe form of SJS.
A man in his 20s experienced life-threatening blistering covering 60 percent of his body, including his face, chest, arms, genitals, legs and feet soles.
Most patients are now recovering. No deaths have been reported.
HSA stated that modafinil and armodafinil are not registered in Singapore and should only be taken under strict medical supervision.
In some countries, these drugs are available by prescription for specific conditions like narcolepsy, which affects a person’s ability to sleep or stay awake.
Associate Professor Lee Haur Yueh, Senior Consultant at Singapore General Hospital’s Department of Dermatology, who treated some patients, warned that SJS and TEN can lead to organ failure in severe cases.
“The fact that we are seeing a significant number of cases from armodafinil and modafinil suggests that the risk associated with these medicines is particularly high,” Prof Lee said.
Beyond skin reactions, these medicines can cause heart problems, hypertension, and psychiatric conditions such as anxiety, hallucinations, or mania.
They also carry a potential risk of dependency due to their stimulant effects on the brain.
HSA advised the public not to share prescription medicines with friends or relatives.
“The medicines may not be suitable or safe for them, and their medical condition may need to be assessed first and managed by a doctor,” the authority stated.
Those found guilty of selling or supplying modafinil and armodafinil without HSA authorization face fines up to $50,000, jail terms up to two years, or both.
People with information on illegal sales of these medicines can contact HSA’s Enforcement Branch at 6866 3485 or email hsa_is@hsa.gov.sg.
