The latest issue of Clinical & Forensic Toxicology News (CFTN) focuses on dissociative drugs of abuse and how these street drugs have accumulated new family members over the last 50 years, many of which are distributed with ease over the internet. Labs should be aware that this group of drugs exists—and is evolving, according to Matthew D. Krasowski, MD, PhD, chair of the CFTN editorial advisory board and an author of issue’s lead article, “Dissociative Drugs of Abuse: Growing Family Includes Ketamine, Phencyclidine, and Their Analogs.”

“This is similar to the pattern seen with other classes of designer drugs (e.g., amphetamines, benzodiazepines, opioids). The dark web particularly facilitates distribution of these type of designer drugs,” Krasowski, who co-wrote the article with Kenichi Tamama, MD, PhD, told CLN Stat.

CFTN is a quarterly AACC/College of American Pathologists (CAP) educational newsletter for toxicology laboratories and individuals with an interest in toxicology. Each issue highlights topics of interest to the clinical and forensic toxicology fields.

Abuse of ketamine and phencyclidine (PCP) has been thoroughly documented over the past 50 years or so. “Recently, analogs of ketamine and PCP have appeared on the street and via Internet sources. Some of these analogs were synthesized and characterized decades ago as potential pharmaceuticals but have now emerged as ‘designer’ dissociative drugs of abuse,” wrote Krasowski, MD, PhD, a clinical professor and vice chair of clinical pathology and laboratory services in the department of pathology at the University of Iowa Hospitals and Clinics in Iowa City, and Tamama, associate professor and medical director of the clinical toxicology laboratory in the department of pathology at the University of Pittsburgh Medical Center.

Krasowski and Tamama summarize the history of ketamine and PCP as drugs of abuse, the laboratory tests used to detect each drug, the evolution of their subsequent analogs, and the regulatory status of these drugs. “The rates of abuse of these dissociative drugs is probably low, especially relative to other drugs such as cocaine and opioids. But there really isn't much data outside of case reports or case series for the analogs,” Krasowski said.

With ketamine, clinical toxicology labs face a challenge in that the Food and Drug Administration has yet to approve any immunoassays that screen for it, although several exist. “Ketamine abuse cases can thus be missed unless the level of suspicion is high enough to pursue specialized testing,” Krasowski and Tamama wrote.

Labs generally use immunoassays to detect PCP, confirming results with gas chromatography/mass spectrometry (GC-MS) and liquid chromatography/tandem mass spectrometry, the authors emphasized. 

Many labs doing routine drug of abuse testing will miss ketamine and phencyclidine analogs, Krasowski indicated. “Some of the ketamine and PCP analogs may cause positive screens on PCP immunoassays,” Krasowski commented. “For clinicians and labs trying to interpret results, it is possible that positive PCP screens from these drugs may be attributed to better-known cross-reactive drugs such as DXM that could cause similar clinical presentations.” He offered that GC-MS for broad drug identification might be able to identify these drugs.

CFTN’s December issue also featured advice from an experienced forensic witness on providing expert testimony. Kamisha L. Johnson-Davis, PhD, rounded off the issue by summarizing the events at the 2018 International Association of Therapeutic Drug Monitoring and Clinical Toxicology Congress in Brisbane, Australia. “The congress was filled with engaging topics in therapeutic drug monitoring and clinical toxicology. There were high-quality oral and poster presentations from scientists and physicians from around the world,” she wrote. The issue also included a news brief about FDA’s recent warnings on heavy metals in kratom products.

CFTN is an educational service of the Forensic Urine Drug Testing (FUDT) Accreditation Program co-sponsored by AACC and CAP. Individual subscriptions are also available; the regular price is $65, and AACC members pay $45. Subscribers are eligible to receive 4 ACCENT continuing education credits per year, 1 credit per quarterly issue.