A 14-month-old boy was allegedly dispensed four times the dosage of a cough medication for his age, and was rushed to hospital after a suspected overdose.
The boy had been coughing, said his mother Belinda Lum, 33, and she had taken him to YSL Bedok Clinic and Surgery last Wednesday.
They were seen by a doctor there and given a bottle of Fedac syrup, with instructions to take 10ml of the medicine three times a day.
Ms Lum said her son then "fell into a very deep sleep".
Suspecting that he was suffering from an overdose, she rushed him to Gleneagles Hospital in the early hours of last Thursday.
He was given an antidote, said Ms Lum, who is going by the name she used in an online fund-raising appeal relating to the incident.
On Sunday, she took him to a paediatric neurologist at Mount Elizabeth Orchard hospital as his hands were trembling.
Speaking to The Straits Times, Ms Lum, who is self-employed, said she met the Bedok North clinic's doctor and manager after the incident. "It was the clinic assistant who dispensed the medication wrongly. I've asked for compensation and a public apology," she said.
She has also made an appointment to lodge a complaint with the Singapore Medical Council.
She first shared her story on fund-raising platform Give.asia. She said it was to encourage people to share her story on Facebook to raise awareness of the incident. She donated $1 to charity for each share.
Dr Yik Keng Yeong, who runs Tan and Yik Clinic and Surgery in Bishan, said that a child as young as Ms Lum's son should be given only 1.5ml to 2.5ml of Fedac each time.
The medicine also treats other cold symptoms, as well as allergies.
Dr Yik, who does not prescribe Fedac to young children, said: "10ml is an adult's dosage. Overdosing on Fedac can cause heart palpitations and sedation. For this case, hopefully the patient will not develop long-term complications."
The Health Sciences Authority states on its website that Fedac in tablet or syrup form should not be given to children under two.
But, Dr Yik said, some general practitioners dispense medication meant for older children and adults, as they do not usually stock medication specific to young children. "Therefore, care must be taken in prescribing such medication in lower doses."
In response to queries from The Straits Times, YSL's parent company, Qualitas Medical Group, said it is aware of the incident at its clinic. "The reports are deeply concerning and we are investigating the matter thoroughly. Our heart goes out to the parents who must have gone through great distress.
"We have been following up with the parents since the incident, and are relieved to hear that the infant has since recovered. We are continuing to engage the parents and we wish the patient well."
Correction note: This story was updated to clarify that the boy was dispensed, not prescribed, the wrong dosage.