Frequent Ketamine Use and Gastrointestinal, Liver and Biliary Sequelae
Condition: Gastritis; Peptic Ulcer Disease; Cholangiopathy; Liver Fibrosis
MeSH terms: Liver Cirrhosis; Gastritis; Peptic Ulcer
Study type: Observational

Summary: 
      30% of ketamine users complain of abdominal discomfort. Long-term ketamine use is associated
      with hepatotoxicity and pathologic changes to the biliary tract. Yet the prevalence of
      gastrointestinal and hepatobiliary pathologies in ketamine users has not been well-described.
      The investigators plan to recruit a large number of ketamine users based on referrals from
      different Psychiatry clusters in Hong Kong and to investigate the underlying cause of
      abdominal discomfort, describe the prevalence of different gastrointestinal and hepatobiliary
      pathologies and describe their long-term outcome.
    

Detailed description: 
      The recreational use of psychotropic drugs has been increasing over the past 2 decades in
      Hong Kong. Ketamine hydrochloride is currently one of the most popular recreational drugs in
      Hong Kong, and its recreational use is also increasing in the United Kingdom and Europe.
      Inhalation of ketamine could result in hallucinations, out-of-the-body experiences and
      psychological dissociation, making it popular among young adults. One of the well-known side
      effects of ketamine is bladder dysfunction, which is seen in one-quarter of chronic ketamine
      users .

      Ketamine has also been known to be associated with gastrointestinal symptoms. Colicky
      epigastric / abdominal discomfort in ketamine users, known as "K-cramps", has been reported
      in 33.3% of frequent ketamine users, and is the second-most common symptom of presentation
      (21%) among ketamine users in the emergency department . Nonetheless, the underlying etiology
      resulting in this abdominal discomfort remains poorly defined. A possible etiology is
      intestinal motility disorders, since ketamine interferes with gastric motility. Another
      possible cause could be ketamine-related cholangiopathy, which has been described in both
      Asia and Western countries. Another possible cause could be ketamine-related liver
      dysfunction, which is seen in 16% of ketamine users. Chronic ketamine hepatotoxicity is
      associated with mitochondrial liver injury , and could result in bridging liver fibrosis.

      We plan to recruit subjects from ketamine users seeking medical attention at substance abuse
      clinics in different psychiatric clusters in Hong Kong. A screening log will be kept on the
      total number of ketamine users attending different substance abuse clinics and the number of
      potential subjects referred to our center.

      Baseline sociodemographic information will be obtained. A standardized method will be used to
      assess and quantify the degree of ketamine use, as well as the recreational use of other
      psychotropic drugs (e.g. ecstasy, methamphetamine, marijuana etc.) and alcohol intake.
      Subjects will then be assessed for the presence or absence of dyspepsia, biliary-type
      abdominal pain， gastroparesis or other abdominal symptoms following standard criteria.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Recreational use of ketamine with frequency at least twice per month over 6 months within
        the last 2 years, with or without other illicit psychotropic drug.
      
Biospecimen description: 
      Saved plasma samples Gastric antral and duodenal histology obtained by upper GI endoscopy
    
Keywords: ketamine; abuse; abdominal discomfort; cholangiopathy