Toxicology Literature of Note
See references at the end of post
Hydrogen sulfide is a toxin often associated with sewers (smells like rotten eggs) and leads to death rapidly. There is concern that it could be used as a weapon, and unfortunately there is no antidote. This proof of concept study looks at the use of midazolam to prevent toxicity, as well as prevent delayed neurological sequela.
An interesting editorial on the use of pralidoxime (2-PAM) for poisoning with organophosphates, which is a major issue in Asia due to availability and a lack of regulation on pesticides. I personally did not know that pralidoxime is not on the WHO’s essential drug list because we do not know which patients benefit from it.
Of note, during fellowship we had a patient ingest Malathion which he purchased from Home Depot. So although rare, these poisonings can be seen in the US. For now, the correct answer is to give 2-PAM for OP ingestions, but that may change.
This small study looks at utilizing ketamine in the setting of alcohol withdrawal. It is very important to note that all patients in this study also received a lorazepam infusion, and benzodiazepines (and barbiturates) remain the drug of choice in this condition. Although withdrawal also involves the NMDA receptor, which ketamine antagonizes, this drug does not affect the GABA receptor. I am interested to see the letters this author may receive on this paper, and will update you all next month.
In this week’s The Tox and The Hound post, David Juurlink, a brilliant researcher and clinical toxicologist in Toronto, lays out his argument for why you should not be prescribing Tramadol. And before anyone asks what the picture means or gets angry by it, that is actually a brand name of a tramadol. . .
Toxicology in the News
Take a look back to last month’s Tox Update “Morels and False Morels!” This college student found some yummy morel mushrooms and posted his haul on Instagram. Not long after eating them . . . no, he did not have a seizure. Rather the cops knocked on his door! See what happened in the below story. . . disclaimer some strong language right at the beginning. . .
Walmart and Sam’s Club are limiting the amount of opioids a patient is able to fill to a one-week’s supply. Although this likely will not affect us (in NYC you should only be prescribing a 3 day course of opioids), this is another way companies are attempting to prevent opioid deaths.
An interesting, and controversial look at the incidence of overdoses death pre- and post- implementation of prescription drug monitoring programs.
Toxicology Toxin of the Month
April showers bring May flowers . . . but it seems like we are still stuck in April with all the rain we’ve been hit with. This month, lets take a look at this pretty flower, with its large green leaves:
This is the mayapple (Podophyllum peltatum) and it has some toxic roots!
Podophyllum resin is the dry, alcoholic extract of the rhizomes and roots of this plant. It consists of up to 20% podophyllotoxin, α- and β-peltatin, desoxypodophyllotoxin, and dehydropodophyllotoxin. Podophyllum resin containing podophyllin is available by prescription for topical treatment of venereal warts. Its medicinal derivative, etoposide, is used for a range of neoplastic diseases. Podophyllum is used as a popular traditional Chinese medicine.
As a group, they disrupt tubulin formation, producing multisystem organ failure. Poisonings are caused by misidentification and adulteration.
GI symptoms including vomiting are prominent after ingestion, but onset of symptoms may be significantly delayed. Acute, severe sensorimotor neuropathy and bone marrow suppression following transient leukocytosis can occur even after acute exposures and may be directly related to inhibition of microtubule assembly. Lethargy, confusion, encephalopathy, autonomic instability, sensory ataxia, and death are described following large exposures, but poisoning has also occurred after “therapeutic” doses of a popular traditional Chinese medicine.
Glutamic acid has been used to prevent vincristine-induced peripheral neuropathy and would be a reasonable therapy following podophyllin ingestion.
Shah P, McDowell M, Ebisu R, Hanif T, Toerne T. Adjunctive Use of Ketamine for Benzodiazepine-Resistant Severe Alcohol Withdrawal: a Retrospective Evaluation. J Med Toxicol. 2018 May 10.
Eddleston M. Are Oximes Still Indicated for Acute Organophosphorus Insecticide Self-Poisoning? J Med Toxicol. 2018 Mar;14(1):1-2.
Anantharam P, Kim DS, Whitley EM, Mahama B, Imerman P, Padhi P, Rumbeiha WK. Midazolam Efficacy Against Acute Hydrogen Sulfide-Induced Mortality and Neurotoxicity. J Med Toxicol. 2018 Mar;14(1):79-90.