Naturally occurring alkaloid analgesics known as Opoids are derived from the opium poppy Papaver sominiferum. Typically, the seedpods are scored and the unify exudates contains morphine, codeine, and numerous other alkaloids, such as papaverine and thebaine. Natural Opoids, including opium, tincture of opium, and paregoric, ingredients that have been used as analgesics or drugs of abuse for centuries. There is strong confirmation of the use of opium in the Sumerian culture as early as 8500 BCE, and the writings of Theophrastus around 200 BCE describe the use of opium in Greek medicine.
In the 1800s and 1900s, synthetic and semi-synthetic derivatives of morphine and codeine were developed in an effort to augment the strength of analgesia and reduce unwanted side effects. Diacetylmorphine was synthesized in 1874 and in 1898, it was introduced as a nonaddicting, analgesic, anti-tussive, and anti-diarrheal. The Opoid drug class includes numerous compounds that are structurally related to morphine and numerous compounds that are pharmacologically related, but structurally unrelated. A wide range of Opoids has been isolated from opium and a wide range of both structurally and pharmacologically related compounds have been synthesized. Table 10.1 includes a list of Opoids and their synonyms.
Though not all of the compounds listed in Table 10-1 are covered in this review, this table indicates the large number of compounds that have Opoid action. All of these compounds have varying degrees of anti-nociceptive, anti-tussive, and anti-diarrheal effects. Additionally, all the compounds have varying impairing effects and abuse potential. For workplace drug testing, the primary concern has traditionally been the detection of heroin use. However, the testing for Opoids has become more complicated as prescription Opoids has become more widely available. Diversion and abuse of legally produced Opoids have become a significant concern to many employers, as has interest in testing populations that have higher potential for abuse of legally manufactured drugs, such as medical professionals.
This and the increasing trend to test patients in pain management programs to ensure compliance has resulted in a greater variety of immunoassays for more opoids and additional testing for Opoids. This chapter will discuss some issues for some of the dominant Opoids including their pharmacology/pharmacokinetics, some analytical issues, and some interpretive issues. As with all urine testing, the determination of impairment of an individual based upon urine results is inappropriate and the issues discussed relate to the potential for misidentification of exposure, not whether or not the individual intended to use or was impaired based upon a single urine result typical of workplace testing.