The Drug Enforcement Administration (DEA) provided the following explantion of the similarities and differences between Marinol, Dronabinol, and Delta-9-Tetrahydrocannabinol (THC) in 1999 and 2002 in correspondence related to the 1995 cannabis rescheduling petition.

In a letter to petitioners on June 28, 1999 the DEA provided the following clarification:

A prefatory note is warranted to clarify the distinction between "Marinol" and "dronabinol." Although these terms are sometimes mistakenly used interchangeably, they have distinct meanings. Dronabinol is the United States Adopted Name for the substance (-)-[Delta-9]-(trans)-tetrahydrocannabinol (hereafter "(-)-Δ-9-(trans)-THC", which is thought to be the primary psychoactive ingredient in marijuana. See 21 C.F.R. § 1308.12(f)(1). Marinol is the brand name of a product approved by the Food and Drug Administrtion (FDA) that contains synthetically manufactured dronabinol in sesame oil and encapsulated in a soft gelatin capsule. Id. Dronabinol is the active ingredient in Marinol. Dronabinol, in its pure form, is a schedule I controlled substance since it is one of the tetrahydrocannabinols and it has no currently accepted medical use in treatment in the United States. See 21 U.S.C. § 812(b)(1); 21 C.F.R. §1308.11(d)(27). Marinol, in contrast, has an accepted medical use and is a schedule II substance [editors note: Marinol has since been rescheduled to schedule III]. See 21 C.F.R. 1308.12(f)(1); 51 Fed. Reg. 17,476 (1986) (DEA final rule transferring Marinol from schedule I to schedule II following FDA approval of the drug for marketing). It was approved for marketing by the FDA in 1985 for the treatment of nausea and vomiting asociated with cancer chemotherapy. Id. In 1992, FDA expanded Marinol's approved indications to include treatment of anorexia associated with weight loss in patients with AIDS. (1)

In additional correspondance on September 26, 2002 the DEA repeated this clarification and noted Marinol's recent rescheduling as a schedule III drug::

In a letter dated June 28, 1999, the Administrtor of DEA clarified . . . the point that "dronabinol" os the United States Adopted Name for the substance (-)-Δ-9-(trans)-tetrahydrocannabinol (also designated (-)-[Delta-9]-(trans)-THC), which is generally accepted as the primary psychoactive ingredient in marijuana. See 21 C.F.R. § 1308.12(f)(1). Marinol is the brand name of a specific pharmaceutical product approved by the Food and Drug Administration (FDA) that contains synthetically manufactured dronabinol in sesame oil and encapsulated in a soft gelatin capsule. Id. Dronabinol is tha active ingredient in Marinol. The specific product formulation along, Marinol (dronabinol in sesame oil and encapsulated in a soft gelatin capsule), remains in schedule III. See 64 FR, 35928, 21 C.F.R. § 1308.13 (g)(1). Dronabinol, in its pure form, is a Schedule I controlled substance since it is one of the tetrahydrocannabinols and it has no currently accepted medical use in the United States. See 21 U.S.C. § 812(b)(1); 21 C.F.R. §1308.11(d)(27). (2)

In plain English, the DEA explains that for regulatory purposes THC has been renamed dronabinol, and that it only has an accepted medical use when it is mixed with sesame oil and placed in a capsule. This semantic exercise allows the DEA to deny that THC has an accepted medical use in the United States. THC, according to DEA, is the same chemical as dronabinol, which has an accepted medical use when it is placed in a gelatin capsule and referred to as Marinol. Despite the fact that THC, dronabinol, and Marinol all refer to the same active ingredient, DEA insists that the name of THC be changed twice-over before it can be referred to as a drug with accepted medical use. While this is precisely correct in legal and regulatory contexts, DEA's semantic exercise begs reference Shakespeare's famous observation: "That which we call a rose, By any other name would smell as sweet." (3)

Notes

(1) Donnie Marshall, Deputy Administrator DEA, Letter to Simore Monesebian, July 28, 1999.
(2) John B. Brown, Deputy Administrator DEA Letter to Jon Gettman, September 26, 2002.
(3) William Shakespeare, "Romeo and Juliet", Act 2 scene 2.