SINGAPORE - The Health Sciences Authority (HSA) on Monday warned the public not to consume modafinil or armodafinil that was not prescribed by a doctor or used under close medical supervision, after three men were hospitalised between August and October after consuming these drugs.

The three men, who were all in their 30s and who took the drugs in a bid to improve alertness, suffered severe adverse reactions. They had obtained the drugs from friends or street peddlers.

One man had obtained modafinil from a friend, and took it only once. But over the next few days, he started to feel unwell, with a fever, multiple mouth ulcers and conjunctivitis. These were accompanied by a severe rash, which started on the neck and subsequently spread to other parts of the body.

He was diagnosed with Stevens-Johnson syndrome (SJS), a life-threatening skin condition with blistering and severe peeling of the skin, and was hospitalised.

A second man ended up in the hospital with SJS after consuming armodafinil, which he had obtained from an illegal peddler in Geylang.

This man had consumed the drug for more than a month to stay alert while working. He suffered from a severe skin reaction that started with a fever and rash, and progressed to skin blistering and multiple mouth ulcers. The severe painful rashes subsequently spread to the whole body.

The third man obtained armodafinil from a friend to stay awake during the day. After taking it a few times, he developed multiple mouth ulcers, inflammation of the mouth, experienced pain when swallowing, and was unable to eat or talk. He developed conjunctivitis and was subsequently hospitalised.

According to the United States’ National Centre for Biotechnology Information, modafinil is a non-amphetamine central nervous system stimulant with wakefulness-promoting properties. It is used to treat conditions that cause excessive daytime sleepiness. In the US, it is approved by the Food and Drug Administration to treat adults who suffer from narcolepsy, sleep work shift disorder and obstructive sleep apnea. Armodafinil is also a “wake-promoting agent” that can be used to treat the same conditions.

The HSA said that modafinil and armodafinil are not registered in Singapore, though they are available in some countries as prescription medicines. They are potent medicines that can cause serious side effects such as heart problems, hypertension, and psychiatric conditions including anxiety, hallucinations or mania. There have also been reported cases of serious skin conditions such as SJS and toxic epidermal necrolysis, resulting in hospitalisation, serious complications, and even death, it added.

Those who recover may suffer from long-term complications including skin scarring, hair loss and visual impairment such as increased sensitivity to light and blindness, said the HSA. Other vital organs, including the lungs, may also be permanently affected.

“There have been reports of individuals taking modafinil or armodafinil for the purpose of improving alertness or as ‘cognitive enhancers’ to improve focus and memory. Self-medication with modafinil or armodafinil for these purposes is not appropriate and can be harmful,” warned the HSA. It added that both drugs “carry a potential risk of dependency due to their stimulant effects on the brain”.

“If there is a clinical need, doctors can apply to HSA to bring in modafinil or armodafinil for their patients’ medical conditions, such as narcolepsy, and patients would have to be under strict medical supervision,” it explained.

The HSA advised consumers to be cautious about obtaining health products from unfamiliar sources, even if these are recommended by friends or relatives. One cannot be sure of what these products contain, or where and how they were made.

Potent prescription medicines should not be shared with or supplied to others, even if medical conditions appear to be similar.

The authority also warned that the supply and sale of an unregistered health product, such as modafinil or armodafinil, is an offence under the Health Products Act, unless the HSA has authorised it for use by a doctor for patients under his care. If convicted, offenders can face a fine up to $50,000, a jail term of up to two years, or both.

Members of the public who have any information on the illegal sale and supply of modafinil or armodafinil may contact HSA on 6866-3485 during office hours or send an e-mail to hsa_is@hsa.gov.sg