A recent multistate outbreak of coagulopathy following synthetic cannabinoid use was attributed to the presence of the vitamin K-dependent antagonist brodifacoum-the blood thinner used in rat poison. Since the initial case, seen a year ago in Illinois, more than 300 people have been treated in 11 states for serious bleeding after exposure, and at least eight deaths have been reported.
Marketed as herbal products having effects similar to marijuana, synthetic cannabinoids are made from plant materials treated with chemicals that act on the same brain receptors as tetrahydrocannabinol (THC), the psychoactive ingredient in marijuana. Hundreds of these manufactured products are available for purchase at convenience stores and online, as well as on the street. Often referred to as "legal weed" or "fake weed," common commercial names include Spice and K2.
Whether smoked or ingested, synthetic cannabinoids alter mental status; but unlike marijuana, they can have serious adverse effects including agitation, confusion, hallucinations, tachypnea, tachycardia, and vomiting. Life-threatening reactions to the chemical combinations include myocardial infarction, rhabdomyolysis, and kidney failure.
In the recent outbreak, patients presented with bruising, nosebleeds, bleeding gums, excessive menstrual bleeding, hematemesis, hemoptysis, or hematuria. The international normalized ratio, part of the coagulation profile, identified severe coagulopathy.
Nurses should suspect vitamin K-dependent antagonist coagulopathy in patients with a history of or suspected drug use who present with symptomatic or laboratory-confirmed coagulopathy and should ask about synthetic cannabinoid use. The treatment is a lengthy course of oral Vitamin K1 therapy and counseling against further use. Most problematic in the current outbreak is that during follow-up, some patients had blood brodifacoum concentrations higher than those initially obtained, indicating that they continued or resumed use.
It's unclear what effect the trend among states to legalize marijuana will be on synthetic cannabinoids. A fear is that it will exaggerate the perception among youth that synthetic cannabinoids are safe, although there is evidence from other countries that decriminalization of marijuana reduces synthetic cannabinoid use. Surveys show that users prefer natural cannabis, but that some people deliberately use synthetic cannabinoids to avoid detection of marijuana's THC in urine. More information about synthetic cannabinoids is available from the CDC at http://www.cdc.gov/nceh/hsb/chemicals/sc/default.html.-Joan Zolot, PA