Toxicology on the Web: recent postings

April 22, 2012, 12:20 am

Two recent educational posts that are worth checking out:

At Life in the Fast Lane, in their series of toxicology conundrums,  there is a good quick review of lithium toxicity organized in a question-and-answer format.

At the HQMedEd podcast, Dr. Jon B. Cole from Hennepin County Medical Center  presents a 30-minute lecture on “Pitfalls of the Urine Drug Screen“. Some important take-home lessons from the lecture:

  • Ranitidine and labetalol will cause a false-positive for amphetamines on many urine drug screen (UDS) tests.
  • UDS for benzodiazepines gives a large number of false positives, basically picks up only diazepam, and will miss clonazepam (Klonopin), alprazolam (Xanax), lorazepam (Ativan), and midazolam (Versed).
  • UDS for opiates can have false positives caused by ingestion of poppy seeds, imipramine, or quinolones.
  • UDS for phencyclidine can have many false positives caused by other drugs such as ketamine, dextromethorphan, tramadol, venlafaxine, and ibuprofen, among others.
  • Immunoassay UDS for methadone can be falsely-positive in the prescience of diphenhydramine or doxylamine.

I also learned from Dr. Coles’ lecture the definition of “3 Stooges Syndrome“.

The entire lecture is organized and concise and well-worth listening to.

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