Clinical pattern and prevalence of upper gastrointestinal toxicity in patients abusing ketamine.

OBJECTIVE: Evaluations of upper gastrointestinal toxicity from ketamine abuse are uncommon. This study investigated the clinical pattern of upper gastrointestinal symptoms in patients inhaling ketamine. METHODS: In a cross-sectional study of 611 consecutive patients who were seeking treatment for ketamine uropathy in a tertiary hospital setting between August 2008 and June 2016, their clinical pattern of upper gastrointestinal symptoms was evaluated and compared with a control population of 804 non-users. RESULTS: A total of 168 (27.5%) patients abusing ketamine (mean age 26.3 years, 58.9% female) reported the presence of upper gastrointestinal symptoms. These symptoms were significantly more prevalent in patients inhaling ketamine than in those who were not (27.5% vs 5.2%, P < 0.001). Their mean duration of ketamine abuse before symptom presentation was 5.0 ± 3.1 years. The presenting symptoms included epigastric pain (n = 155, 25.4%), recurrent vomiting (n = 48, 7.9%), anemia (n = 36, 5.9%) and gastrointestinal bleeding (n = 20, 3.3%). Uropathy symptoms were preceded by upper gastrointestinal symptoms for 4.4 ± 3.0 years in 141 (83.9%) patients. Logistic regression showed that elder age (odds ratio [OR] 1.06, P = 0.04), active abuser status (OR 1.60, P = 0.04) and longer duration of ketamine abuse (OR 1.00, P = 0.04) were independent factors associated with upper gastrointestinal toxicity. CONCLUSIONS: Although epigastric symptoms are unusual in the young population, upper gastrointestinal toxicity was highly prevalent in those inhaling ketamine. Enquiries about ketamine abuse are recommended when assessing young patients with epigastric symptoms.