We observed a precipitous decrease in GHB exposures reported to the California Poison Control System for 1999 through 2003, which parallels decreasing GHB exposures reported nationally through the American Association of Poison Control Centers during 2001 to 2003 and is consistent with the overall trend in Drug Abuse Warning Network data in 2002 to 2003, although not from earlier years. In contrast, National Institute for Drug Abuse survey data on GHB use among high school students did not indicate a temporal decrease during the same period, although reported use among college students and young adults did decrease in 2003 compared with 2002.
There could be multiple explanations for the apparent decrease in incidence evident in GHB poison center case reports. First, this may indeed reflect the true incidence in GHB toxicity and underlying abuse. Second, the decrease in events may reflect a decreased frequency of adverse events without a decrease in overall GHB usage. Finally, the apparent decrease could be spurious or due to random variability.
Considering the findings of all 3 case incidence surveillance systems (California Poison Control System, American Association of Poison Control Centers, and Drug Abuse Warning Network), the observed decrease in GHB-related reporting to the California Poison Control System is likely to represent a true decrease in adverse GHB-related events in patients presenting for ED care. Increased familiarity of ED staff with GHB overdoses may result in fewer consultations with poison centers and therefore explain a differential decrease comparing poison center to Drug Abuse Warning Network data (the latter directly samples ED records without a physician reporting step). The observation that malicious event reporting decreased less sharply (proportionally increasing with time) may further support the presumption that although health care practitioners and even the lay public are more familiar with GHB adverse effects and thus may be less likely to report misadventures, they still contact a poison center for consultation in certain exposure situations.
In response to the growing abuse and danger of GHB, the Controlled Substances Act was amended in 2000 to add GHB. Illicit GHB is a Schedule I agent.12
Nonetheless, in 2002 the US Food and Drug Administration approved GHB (Xyrem, Orphan Medical, Minnetonka, MN) as a Schedule III agent for the treatment of cataplexy, thus making it available by prescription. γ
-Butyrolactone is a List 1 controlled “chemical” and not treated as a drug itself. List 1 chemicals are defined as “important to the manufacture of a controlled substance.” Thus, based on these 2 drug and chemical restrictions, with the exception of physicianprescribed Xyrem, it is now illegal to possess, manufacture, or sell GHB, gammabutyrolactone (GBL), gammavalerolactone (GVL), or 1,4 butendiol (BD) when the intent is for ingestion. These changes have limited substantially the availability of GHB. These restrictions may have had a chilling effect on the willingness of people to call the California Poison Control System to report use of an illegal substance through fear of possible legal sanction, lowering reporting but not actual numbers of adverse events. The use of GHB congeners may also be an explanation for the decreasing incidence of California Poison Control System reports. GHB restrictions, as described above, have a significant loophole that allows for the legal sale of GHB congeners as long as the use is “not
intended for ingestion.” There are still Internet Web sites marketing GHB congeners masked as cleaning chemicals and other products. There is also anecdotal evidence that the GHB congener γ
-valerolactone may have less potency than GHB, resulting in lower incidence of adverse events.13-15
Thus, changing patterns in congener use could alter adverse event frequencies, even with the relatively stable prevalence of use observed in the National Institute for Drug Abuse survey.
Finally, patterns of illicit drug use for many substances are inherently variable with time, driven in part by a seemingly endless search by individuals for an altered state of consciousness. Sedative hypnotics were popular in the 1940s and 1950s, LSD was in vogue in the 1960s, cocaine seemed dominant in the 1980s,16
and the attractiveness of amphetamines in the 20th century has continued unabated as we enter the 21st century. Ultimately, the increase and decrease of GHB throughout the last decade may merely reflect the same pattern.
We identified a precipitous decrease in GHB-related calls to the California Poison Control System and decreases in national poison center and Drug Abuse Warning Network reporting as well. There was no time trend in the California Poison Control System case severity mix. Overall, the death cases were infrequent and were the result of out-of-hospital events. Although it is likely that true incidence has indeed decreased, surveillance estimates using multiple data sources should be used to confirm this trend and to link these observations to survey data on drug use patterns.