The research team of Department of Medicine, HKU, and Department of Surgery, North District Hospital, performed magnetic resonance imaging (MRI) for ketamine abusers and demonstrated ketamine also damages the biliary system. This damage may be reversible after stopping ketamine abuse.

Undoing Damage Done

Research team finds that long-term ketamine abuse harms the biliary system, but the damage can be repaired if the user quits the drug.

​ The study enhances our understanding
of the toxic effects of ketamine on the
biliary system and the liver. Hopefully
the findings will motivate drug abusers
to quit.

Dr Walter Seto Wai-kay

More popular than cocaine

“Ketamine abuse, particularly among adolescents and young adults, is very common in Hong Kong and South East Asia,” said Dr Seto. “It’s more popular than cocaine. The drug comes in powder form so it is inhaled like cocaine – and Asians prefer this as they tend not to like injecting themselves. Also, unlike cocaine, it is cheap.”

Working with Dr Mak Siu-king, Associate Consultant in the NDH’s Department of Surgery, the research team recruited ketamine abusers from the community via a network of charitable NGOs which offer assistance to drug abusers in Hong Kong. Participants were given an MRI of the biliary system as well as blood tests and clinical assessment. The MRI findings were then interpreted by two radiologists who did not know the clinical profiles of the participants.

A subset of participants, including individuals who had subsequently quit ketamine, were invited for a second clinical assessment and MRI scan. “One year on, the damage to the biliary duct in the patients who had quit was found to have completely gone,” said Dr Seto. “Their liver enzymes were normal, they had no stomach pain.”

Dr Seto’s association with ketamine research goes back seven years to when he wrote a report on the damage the drug causes to the body. “No one else had written about it at the time,” he said. “Abuse of ketamine was not common in the Western world then, but now it is increasing in parallel with the increasing Asian populations of big cities there.”

Ketamine is a strong hallucinogen which sparks agitation and aggression and causes reduced awareness of the immediate surroundings, which puts the user in danger of physical harm. Long-term abusers of the drug can also suffer cognitive defects, short-term memory loss and damage to the bladder and kidneys.

Statistics from the Central Registry of Drug Abuse of the Hong Kong government’s Narcotics Division, report ketamine as the most commonly abused psychotropic drug in Hong Kong from 2006 to 2014, and the second most common in 2015. 23.1 per cent of reported drug abusers in Hong Kong used ketamine, with the proportion increasing to 39 per cent in individuals younger than 21 years of age.

The research team recruited 257 ketamine abusers, with an average age of 28.7 years, and who had been abusing ketamine for an average duration of 10.5 years. 72.4 per cent had a history of emergency attendance for abdominal pain and 45.9 per cent for urination problems. 60.3 per cent had elevation of serum ALP, a liver enzyme that reflects biliary tract damage. 159 participants (61.9 per cent) had abnormalities of the biliary system on MRI, with 53.3 per cent of those having damage to the larger biliary ducts while 35.4 per cent had damage to the smaller biliary ducts.

Help from NGOs

Dr Seto admits that getting users to volunteer to take part in the study was difficult at first since few wanted to come forward and admit their addiction. “In the end, NGOs working with drug abusers helped, they persuaded people to volunteer,” he said. “In fact it was only through this study I came to realise just how huge the problem is and, as a result, the huge number of people who are involved in tackling drug abuse in Hong Kong.”

He goes on to say that he believes ketamine abuse to be much more widespread than the authorities realise. “The only statistics available are, first, from hospitals when someone has been admitted and, second, voluntary data – so it seems likely there could be a much bigger problem out there. We hope the results we have found will encourage more people to give up ketamine when they see that they can make a full recovery.” 

Long-term abusers of the psychotropic drug ketamine often experience abdominal pain, frequently have elevated liver enzymes, and also commonly suffer abnormalities of the biliary tract. The clinical profile, risk factors and disease course of such ketamine-related biliary damage had never been investigated properly, until a recent collaborative study between HKU and North District Hospital (NDH), which performed magnetic resonance imaging (MRI) on 257 ketamine users. The results demonstrated that long-term abuse of the drug does result in damage to the biliary system but that this damage may be reversible if the user quits his/her ketamine habit.

“The study enhances our understanding of the toxic effects of ketamine on the biliary system and the liver,” said Dr Walter Seto Wai-kay, Clinical Associate Professor of Gastroenterology and Hepatology in HKU’s Department of Medicine. “Hopefully the findings will motivate drug abusers to quit.”

 A patient describes how her life and health returned to normal after quitting ketamine.