Dronabinol can’t replace medical marijuana

The written record on medicinal marijuana stretches back over 2,000 years, yet after hundreds of studies, experiments, and reports, there is still no consensus about its effects. Other than opiate narcotics, it is hard to think of another medicinal plant that has generated so much controversy.

Back in 1985, the FDA approved dronabinol (trade name Marinol) as a treatment for the nausea and vomiting associated with cancer chemotherapy in patients who failed to respond adequately to conventional treatments. In 1992, the FDA approved another indication — this time as a treatment for appetite loss in people with acquired immunodeficiency syndrome.

The active ingredient in dronabinol is synthetic delta-9-tetrahydrocannabinol (delta-9-THC) and therein lies the controversy.

“Marinol is not marijuana. Marinol's active ingredient is synthesized delta-9-THC, a single compound. The marijuana plant growing in the wild has hundreds of compounds,” says Donald Abrams, MD, a professor of medicine at the University of California San Francisco and a highly regarded Stanford-educated AIDS expert. All of those compounds contribute to the plant's effect when smoked.

“The pharmacokinetics of the drug are such that it can take up to two-and-a-half hours for it to work,” says Abrams. “Compare this to the smoked plant, which reaches a peak plasma concentration in two-and-a-half minutes.”

“If a patient is taking Marinol he needs to take it two-and-a-half hours before it's needed. It does not exhibit the best onset of action.” Adding fuel to the controversy is the price: “Marinol is also very expensive,” says Abrams.

So maybe Marinol, in its present dosage form, isn't going to quell the controversy. But manufacturers are investigating other delivery methods.

Dronabinol coverage increases slowly Formularies that were surveyed are in conventional HMOs (including Medicaid and Medicare), POS plans, PPOs, PBMs, and Medicaid plans. Data presented for 2000 and 2005 only.

Source: MediMedia's Formulary Compass, MediMedia Information Services
MediMedia's Formulary Compass is a constantly updated compilation of formulary information containing product position for over 3,000 separate drug benefit designs for HMOs, PPOs, PBMs, POS plans, Medicaid, employer groups, and private insurers.