Ketamine is one of the most commonly abused psychotropic drugs in Hong Kong, especially among adolescent and young adult substance abusers. While long-term ketamine abuse is known to affect bladder function, its effect on the biliary system and liver function has not been well-investigated. The research team of Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong (HKU), and Department of Surgery, North District Hospital (NDH), 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.
Ketamine abuse and its harmful effects
According to the Central Registry of Drug Abuse of the Narcotics Division, The Government of the Hong Kong SAR, in 2015, the average age of reported drug abusers in Hong Kong was 38 years, of which 19.0% took more than one drug. 77% started substance abuse before the age of 21 years. Ketamine was the most commonly abused psychotropic drug in Hong Kong from 2006 to 2014, and the second most common in 2015. 23.1% of reported drug abusers used ketamine, with the proportion increasing to 39.0% in individuals younger than 21 years of age. Ketamine abuse is also common in East and South-East Asia.
Ketamine is a strong hallucinogen. Abusers may become agitated, aggressive, with a reduced awareness of the immediate surroundings, exposing users to potential physical harm. Long-term ketamine use is associated with cognitive deficits and memory loss. In addition, bladder damage is common among long-term ketamine abusers, resulting in frequent small volume urination, painful urination and kidney damages. Severe cases may require intensive Urology follow-up and even surgical intervention.
Long-term ketamine abusers often report abdominal pain and have been noted to have elevation of liver enzymes. There have been case series describing abnormalities of the biliary tract in long-term ketamine abusers, but the clinical profile, risk factors and disease course of ketamine-related biliary damage have never been well-investigated.
The research team from HKU and NDH recruited ketamine abusers from the community via a network of non-government charitable organizations that offer assistance to drug abusers in Hong Kong, which include Barnabas Charitable Service Association Limited, Hong Kong Lutheran Social Service and Tung Wah Group of Hospitals CROSS Centre. Study participants are invited for clinical assessment, blood tests and a magnetic resonance imaging (MRI) of the biliary system. MRI findings were interpreted by two radiologists blinded to the clinical profiles of study participants. A subset of participants, including individuals who had subsequently quitted ketamine abuse, were invited for a second clinical assessment and MRI scan.
The research team recruited 257 ketamine abusers, of an average age of 28.7 years, and had been abusing ketamine for an average duration of 10.5 years. 72.4% and 45.9% had a history of emergency attendance for abdominal pain and urination problems respectively. 60.3% had elevation of serum ALP, a liver enzyme that reflects biliary tract damage.
159 participants (61.9%) had abnormalities of the biliary system on MRI. There were different categories of biliary damage; 53.3% had damage to the larger biliary ducts while 35.4% had damage to the smaller biliary ducts. Risk factors for biliary tract damage include elevation of serum ALP, no concomitant use of other drugs of substance abuse, and co-existing urinary symptoms.
Biliary tract damage was reversible in 6 participants who had a second MRI scan after quitting ketamine abuse. These 6 participants also had improvement in abdominal symptoms and normalization of liver enzymes. At the same time, one participant with a longstanding history of ketamine abuse found to have advanced liver cirrhosis, which was likely a result of the continued damage to the biliary system.
Significance of the study and suggestions
The HKU-NDH study confirms biliary tract damage is present in a majority of ketamine abusers. The research team encourages drug abusers with longstanding ketamine use should be screened for biliary tract damage. Priority should be given to individuals with elevation of liver enzymes, solely abusing ketamine and co-existing urinary symptoms.
The reversibility of biliary tract damage after quitting ketamine and the development of liver cirrhosis after longstanding exposure are important public health messages. These should be emphasized in educational efforts when combating against substance abuse.
“The study enhances our understanding of the toxic effects of ketamine on the biliary system and the liver. Hopefully our study findings will motivate current drug abusers to quit, and will encourage our community’s efforts in ‘saying no’ to drug abuse,” says Dr. Walter Seto Wai-kay, Clinical Associate Professor of Gastroenterology and Hepatology of Department of Medicine, Li Ka Shing Faculty of Medicine, HKU.
About the research team
Dr Walter Seto Wai-kay, Clinical Associate Professor of Department of Medicine, Li Ka Shing Faculty of Medicine, HKU has been conducting liver research for many years. Dr Mak Siu-king, Associate Consultant of Department of Surgery, NDH, helped establish the Crisis Accommodation Centre of NDH, a voluntary group of doctors, nurses, occupational therapists and medical social workers who are tackling drug abuse in Hong Kong.
This study was funded by the Beat Drug Fund, Narcotics Division, The Government of the Hong Kong SAR.
Dr Walter Seto Wai-kay, Clinical Associate Professor of Department of Medicine, Li Ka Shing Faculty of Medicine, HKU said that the study enhances our understanding of the toxic effects of ketamine on the biliary system and the liver.
Dr Mak Siu-king, Associate Consultant of Department of Surgery, NDH, hopes that the study findings will motivate current drug abusers to quit, and will encourage our community’s efforts in “saying no” to drug abuse.
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