As hemp extract oil (CBD or cannabidiol) have grown in popularity, research has been done to look in to its effects and safety in humans. A recent article looks into the tolerability of hemp extract oil in humans, essentially the safety of hemp extract oil in humans and its side effects. The article also looked into any possible interactions that hemp extract oil may have if it is taken at the same time as other drugs.
From Cannabidiol: Promises and Pitfalls recently posted on PubMed Central, drug tolerability and interactions are as follows:
"CBD is well tolerated in humans with doses up to 600 mg not resulting in psychotic symptoms (15). In the few small placebo-controlled studies performed, no significant CNS effects were noted. Oral CBD undergoes extensive first-pass metabolism via CYP3A4, with a bioavailability of 6%. Following single doses in humans, the half-life of CBD when taken orally is about 1 to 2 days (1). In vitro studies have shown that CBD is a potent inhibitor of multiple CYP isozymes, including CYP 2C and CYP3A (16, 17). Whether these in vitro observations are relevant at plasma concentrations likely to be seen in patients is unclear. In addition, given its metabolism via CYP3A4, clinical trials of CBD in patients receiving enzyme-inducing AEDs, such as carbamazepine or phenytoin, will require detailed pharmacokinetic studies.
A number of difficulties exist in evaluating published data on CBD or marijuana use for epilepsy. The extremely limited published studies were small, poorly described, and not well designed. Contributing to the difficulty of interpreting published studies, CBD products are not produced under the guidance of good manufacturing practices (GMP) and are not subject to regulations governing labeling, purity, and reliability. In other words, currently, there is no guarantee of consistency between products, or even differing lots produced by the same manufacturer. Without independent testing (e.g. USP certification) of CBD products for content and purity, as well as bioavailability testing of specific products, uncertainty surrounds the use of available CBD products in routine clinical settings."
Studies are ongoing and it is advised that you discuss hemp extract oil with your health care team prior to using the products.
The original study can be found here:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4189631/
In a more recent blog, Living Health and Wellness explores the science-backed benefits of hemp extract (CBD). Read more here.