Study Spotlight #10: Alleviating Concerns about Negative Treatment Synergies When Co-administering THC and Opioids
As early as 1976, researchers from the Asthma Research Unit at the Welsh National Scholl of Medicine in the UK conducted a clinical trial showing that THC has broncho-dilatory effects in humans. Research has since established that the endocannabinoid system (ECS) plays a significant role in respiratory homeostasis and pulmonary function.
Yet, the potentially diverse and detailed effect of various cannabis constituents on respiratory function and ventilatory control remains to be fully explored. Since both can opioids and THC can induce sedation (albeit with significantly different intensities), some physicians and researchers were concerned about the possibility of causing a synergistically detrimental effect on the respiratory actions of patients who consumed both.
An opioid overdose is characterized by a decreased level of consciousness, pinpoint pupils, and sedative effects so severe resulting in respiratory depression, which can lead to hypoxia and death. Immediate interventions with Narcan and manual respiratory support are often necessary to reverse these life-threatening symptoms.
On the other hand, adverse effects from cannabis-only consumption are less severe and not life-threatening. These may include increased dry mouth, changes in cognition (primarily on memory, attention, and concentration), sedation (think “couch-lock”), ataxia (increased risk of falls), drowsiness, dizziness, addiction/withdrawal potential (in fewer than 1 in 20 patients).
Management of cannabis-related adverse effects typically involves supportive care and reassurance; the symptoms usually resolve without long-term consequences.
Now a team of researchers from the Netherlands tested the additive sedative effects hypothesis by conducting a randomized controlled crossover trial on 18 healthy volunteers. Each was given an inhaled, mainly THC-based product (i.e., a pharmaceutical-grade high-THC cannabis variant (21.8% THC; 0.1% CBD) after receiving a placebo or pretreatment with oxycodone 20 mg by mouth.
The resulting data found that THC does not affect ventilatory control when used with opioids (i.e., oxycodone).
In conclusion, while modulating components of the ECS with cannabinoid-based therapeutics can modulate all aspects of pulmonary functions, the co-administration of opioids and THC does appear not to create detrimental effects on ventilatory efforts and control.
Williams, S. J., Hartley, J. P., & Graham, J. D. (1976). Bronchodilator effect of delta1-tetrahydrocannabinol administered by aerosol of asthmatic patients. Thorax, 31(6), 720–723.
Wiese, B. M., Alvarez Reyes, A., Vanderah, T. W., & Largent-Milnes, T. M. (2023). The endocannabinoid system and breathing. Frontiers in neuroscience, 17, 1126004.
van Dam, C. J., van der Schrier, R., van Velzen, M., van Lemmen, M., Simons, P., Kuijpers, K. W. K., Jansen, S., Kowal, M. A., Olofsen, E., Kramers, C., Dahan, A., & Niesters, M. (2023). Inhaled Δ9-tetrahydrocannabinol does not enhance oxycodone-induced respiratory depression: randomised controlled trial in healthy volunteers. British journal of anaesthesia, 130(4), 485–493.
