Wide variation exists in the reported dose of delta-9-tetrahydrocannabinol (Δ 9-THC) needed to produce CNS effects, Dr. Wilsey said. Two recent studies suggest that lower doses of THC provide pain relief similar to that of higher doses, yet decrease the risk for adverse events.5,6
A patient-specific, self-titrating model has therefore been suggested as a useful dosing paradigm for medicinal cannabis, allowing patients to take the lowest effective dose of THC.
“The use of flexible dosing has been previously performed for the treatment of neuropathic pain with nabiximols where patients self-titrated their overall dose and pattern of dosing, according to their response to and tolerance of the medicine,” Dr. Wilsey pointed out, noting that the delayed-onset associated with dronabinol and nabilone may make titration difficult.
Efficacy may vary with formulation
According to Dr. Wilsey, some experts have suggested that whole plant cannabis or ingested marijuana is superior to the FDA-approved cannabis-based medications. The concept may explain why long-marketed oral cannabinoids are not widely used in the US.
“Peak plasma concentrations occur 1 to six hours after ingestion, with a magnitude approximately 10% of that achieved with smoking. It has been postulated that the preference expressed by patients for herbal cannabis is a result of the faster onset and shorter duration of action, allowing titration of dose to the desired effect,” Dr. Wilsey said.
Dr. Wilsey and colleagues plan to compare the efficacy and safety of herbal cannabis and oral Δ 9-THC (dronabinol) directly in a clinical population.
“We plan on performing a randomized, controlled 8-week trial comparing the effectiveness of these two cannabinoid preparations in patients with neuropathic low back pain. In addition to studying efficacy and side effect profiles, we will also perform a driving simulation study to determine the real-world impact of these two cannabinoid treatments,” Dr. Wilsey concluded.
1. Parmar JR, Forrest, Benjamin D, Freeman, Robert A. Medical marijuana patient counseling points for health care professionals based on trends in the medical uses, efficacy, and adverse effects of cannabis-based pharmaceutical drugs.Research in Social and Administrative Pharmacy. 2015. Published online September 16, 2015. doi:10.1016/j.sapharm.2015.09.002
2. Whiting PF, et al. Cannabinoids for medical use: A systematic review and meta-analysis. JAMA. 2015; 313 (24).
3. Ware MA, Ziemianski D. Medical education on cannabis and cannabinoids: Perspectives, challenges, and opportunities. Clin Pharmacol Ther. 2015; 97(6): 548-550.
4. Wilsey B, et al. The medicinal cannabis treatment agreement: Providing information to chronic pain patients via a written document. Clin J Pain. 2014.
5. Wilsey, B, et al. A randomized, placebo-controlled, crossover trial of cannabis cigarettes in neuropathic pain.The Journal of Pain. 2008; 9(6): 506-521.
6. Wilsey, B, et al. Low dose vaporized cannabis significantly improves neuropathic pain. The Journal of Pain. 2013; 14(2): 136-148