Page 419 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

386 SECTION | IV Drugs of Use and Abuse

VetBooks.ir malicious poisoning or other forms of animal abuse. the law. Cocaine has been detected in urine samples from
horses at athletic events (Queiroz-Neto et al., 2002;
Suspected malicious poisoning with illicit drugs has
Kollias-Baker et al., 2003). It is expected that such drugs
been reported (Bischoff et al., 1998).
The pet owner who is aware that the animal ingested would be given in relatively small doses, but dose miscal-
an illegal substance may be reluctant to admit it (Godbold culations can occur. Illicit use of anabolic steroids was
et al., 1979; Kisseberth and Trammel, 1990; reported in 1941 and involved testosterone use, drugging
Dumonceaux, 1995; Welshman, 1986; Frazier et al., with such compounds as stonozolol and androstenedione,
1998; Janczyk et al., 2004; Volmer, 2005). Veterinarians as well as numerous new “designer” anabolic steroids.
are tasked with balancing client confidentiality with legal This continues to be reported in equine athletes (Waller
obligation. The client bringing the pet to a veterinary and Mcleod, 2016). Exposure to plants grown for illicit
clinic is aware that the pet requires medical attention, but drug manufacture has occurred in herbivores. There are
may be unwilling to disclose critical information under reports of lethal marijuana exposure in cattle fed mari-
the threat of legal action. It is prudent for the veterinarian juana hay and horses on pasture (Cardassis, 1951;
to be aware of the local laws concerning animal abuse, Driemeier, 1997). Impaction from the fibrous nature of
drug possession, and their responsibility towards reporting the plant and underlying illnesses probably contributed to
illegal activities. Sadly, animals have been euthanized in the deaths in those cases.
part because of an incomplete history (Smith, 1988). The Anhydrous ammonia is an ingredient in illegal meth-
owner must be made aware that a proper history is amphetamine production. It is also used to instill nitrogen
required if appropriate treatment is to be administered. into the soil for fertilization, and tanks are sometimes
Diagnostic laboratories have screens available to stored near animal facilities. Unscrupulous manufacturers
detect the presence of many illegal drugs, but testing can of the drug steal anhydrous ammonia from farm tanks and
be costly and results are usually not available right away have been known to fail to close the tank valves before
(Janczyk et al., 2004). Over-the-counter testing kits have leaving the premises. The death of 64 out of 260 dairy
been developed for rapid analysis of human urine and cattle in Michigan resulted from anhydrous ammonia theft
are available at pharmacies. One study has found these (Fitzgerald et al., 2006).
kits useful in detection of barbiturates, some opioids,
benzodiazepines, and amphetamines in canine urine, but
less accurate in the detection of other opioids and mari- The Veterinarian and the Drug Enforcement
juana (Teitler, 2009). Based on the author’s experience, Administration
false negatives for marijuana are common with over-the-
Title 21 of the US Code of Federal Regulations estab-
counter test kits. Awareness of the animal’s home situa-
lishes the Drug Enforcement Administration (DEA),
tion, including the neighborhood or the presence of
which classifies drugs into five categories as listed in
adolescent children, can be helpful in determining the
Table 22.1. Because some veterinary drugs, such as keta-
potential for exposure to illegal substances and can give
mine and some opioids, are coveted on the illegal drug
the client or owner the opportunity to explain the expo-
market, failure of the veterinarian to prescribe drugs
sure while diverting blame from themselves. The astute
appropriately has led to the loss of licenses and the risk of
clinician might ask if there was a party in the home
imprisonment (Gloyd, 1982). A veterinarian was fined
when the pet became ill (Kisseberth and Trammel,
and lost his license in 2000 for selling steroids illegally
1990). Pet owners who do admit that their pet ingested
(AVMA News, October 15, 2000), and a few years later,
illegal drugs are not always fully aware of what was
an Internet pharmacy was fined more than $40,000 for
ingested or know only the street name of the drug. Drug
contracting veterinarians to write prescriptions without
dealers often combine drugs or make substitutions, and
examining animals and for dispensing drugs not approved
many drugs are very similar in appearance. The results
by the FDA (AVMA News, April 19, 2002).
of marijuana legalization in US states have been
mixed—clients and owners will be more likely to report
exposures, but exposures have already become more DEPRESSANTS
common.
Substances that have a depressant effect on the central
nervous system (CNS) include marijuana, barbiturates,
Illicit Drugs and Large Animals
opioids, and the club drugs flunitrazepam (Rohypnol) and
Horses may be “doped” to improve athletic performance GHB. Ketamine, a sedative-hypnotic, will be discussed
or to hide soundness or temperament problems. The first with the related compound phencyclidine under the cate-
laws regarding equine doping were put in place in gory of hallucinogens. Depressants act at a variety of
England in 1666, though the practice certainly predates receptor sites within the CNS. Some receptors are named