Daily Dose Q&A

2026-02-13

Cannabinoids can be administered transdermally. Compare CBD's skin permeability to that of THC's.

CBD’s skin permeability is ~ 10x greater than that of THC. Factors affecting transdermal absorption include local blood flow and skin permeability as well as other factors.

Simei, J. L. Q., Souza, J. D. R., Pedrazzi, J. F., Guimarães, F. S., Campos, A. C., Zuardi, A., Hallak, J. E. C., & Crippa, J. A. S. (2024). Research and Clinical Practice Involving the Use of Cannabis Products, with Emphasis on Cannabidiol: A Narrative Review. Pharmaceuticals, 17(12), 1644. https://doi.org/10.3390/ph17121644

2026-02-12

THC and some other cannabinoids lower intra-ocular pressure (IOP). Why aren't cannabinoids typically useful for treating glaucoma?

There are a few reasons why cannabinoids aren't typically useful for treating glaucoma: 1.) They have a short duration of action (approximately 3-4 hours) 2.) Cannabinoids may lower systemic blood pressure and therefore may impair optic nerve perfusion 3.) THC has psychoactive effects which may not be well tolerated by elderly patients (a majority of glaucoma patients are elderly). Of note, "the American Glaucoma Society has stated that medical marijuana is not an acceptable treatment option for glaucoma."

Adamek, A. J., Hussein, M. A., Abdulkarim, I., Orengo-Nania, S., & Sheheitli, H. (2025). An assessment of the prevalence of cannabis use in eye clinic patients and its implications on glaucoma diagnosis and management. International Ophthalmology, 45(1), 484. https://doi.org/10.1007/s10792-025-03846-2 and Joshi, N., Mariam, H., & Kamath, A. (2024). Cannabinoids for the treatment of glaucoma: A review. Medical Cannabis and Cannabinoids, 7(1), 183–192. https://doi.org/10.1159/000538482

2026-02-11

Pets may gain access to and ingest prescription medications or cannabis-derived products. What is the poison control number for animals?

The ASPCA Poison Control phone number is 1-888-426-4435. This is a national number and operates 24/7/365, but unlike the human poison hotline, consultation fees typically apply per case (often referenced around $65-$95 depending on source/plan).

ASPCA.org

2026-02-10

Is continued cannabis use a contraindication to breastfeeding?

In their October 2025 Clinical Consensus No.10: Cannabis Use During Pregnancy and Lactation, The American College of Obstetricians and Gynecologists (ACOG) emphasizes that "health care professionals should advise cessation of cannabis use during pregnancy and lactation. However, continued cannabis use is not a contraindication to breastfeeding, and breastfeeding should not be discouraged." It is important to note that breastfeeding has numerous positive health effects, including decreased rates of infection, asthma, and obesity and improved intellectual development. According to the American College of Obstetrics and Gynecology, there are no medical indications for cannabis use during pregnancy or the postpartum period.

ACOG. (2025). ACOG Clinical Consensus No. 10: Cannabis use during pregnancy and lactation. Obstetrics & Gynecology, 146(4), 600-611. https://doi.org/10.1097/AOG.0000000000006053

2026-02-09

CBD may inhibit the cytochrome P450 enzyme CYP2C19. Does that pose an issue for patients who take CBD with clopidogrel (Plavix)?

Yes. Clopidogrel requires hepatic CYP2C19 metabolism to convert to its active metabolite. In vitro data demonstrate that CBD (at concentrations achieved with CBD doses of 300-1,500 mg/day in humans) may significantly inhibit CYP2C19 activity. Therefore, co-administration may reduce clopidogrel's antiplatelet efficacy and increase the risk of cardiovascular events, especially in individuals with recent coronary stent placement. Clinicians should consider monitoring for signs of reduced clopidogrel activity, such as recurrent angina, thrombosis, or stent occlusion or consider alternative antiplatelet agents which are not dependent on CYP2C19 for bioactivation.

Brown, J. D., & Winterstein, A. G. (2019). Potential adverse drug events and drug-drug interactions with medical and consumer cannabidiol (CBD) use. Journal of Clinical Medicine, 8(7), 989. https://doi.org/10.3390/jcm8070989 Greger, J., Bates, V., Mechtler, L., & Gengo, F. (2020). A review of cannabis and interactions with anticoagulant and antiplatelet agents. Journal of Clinical Pharmacology, 60(4), 432-438. https://doi.org/10.1002/jcph.1557 Jiang, R., Yamaori, S., Takeda, S., Yamamoto, I., & Watanabe, K. (2013). Cannabidiol is a potent inhibitor of the catalytic activity of cytochrome P450 2C19. Drug Metabolism and Pharmacokinetics, 28(4), 332-338. https://doi.org/10.2133/dmpk.DMPK-12-RG-129