A 77-year-old woman who suffered joint pain was given allopurinol, a medication to treat gout, which she started taking on Oct 27 last year.
But Madam Tian Lay Choo developed an allergic reaction to it and died in Tan Tock Seng Hospital (TTSH) on Jan 18.
A coroner's inquiry yesterday found her death to be an "unfortunate medical misadventure". Madam Tian died of toxic epidermal necrolysis, a more severe form of Stevens-Johnson Syndrome (SJS).
The Straits Times has reported that more than 100 people here suffer from the painful and severe skin condition every year.
SJS, which is a serious allergic reaction to certain types of medication, causes skin cells to die and the skin to blister badly.
In rare cases, SJS leads to toxic epidermal necrolysis, characterised by large pieces of skin dying and falling away, which leaves the patient vulnerable to life-threatening infections.
Coroner Marvin Bay said yesterday: "It is therefore essential for medical professionals, patients and their carers to work in close coordination to give and heed medical advice, and be vigilant for the onset of adverse symptoms such as rashes that may signal that an individual is especially susceptible to the medication prescribed."
He added that the patient can then stop taking the medication and seek medical attention before his or her condition gets worse.
Coroner Bay said that according to Madam Tian's son, his wheelchair-bound mother complained of knee pain in October last year and was taken to TTSH for treatment.
She asked for medication to ease her pain and her son recalled that a doctor had made reference to its possible side effects.
However, her son could not remember specific details of the discussion and advice.
He noted that his mother became weaker after taking the medication for about two months.
The skin around her lips was also peeling.
Said the coroner: "He originally believed this to be from dehydration as Madam Tian had been on fluid restriction, as a result of complications from her diabetes and chronic kidney disease."
She later asked to go to TTSH and was warded on Dec 31 last year.
She stopped taking her medication the same day.
Coroner Bay said she had rashes on her body which got worse over time.
She was diagnosed with toxic epidermal necrolysis on Jan 16 and died two days later.