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.
CBD oil is not legal everywhere. It is banned/restricted by countries such as UAE, Dubai, and Saudi Arabia. Although CBD oil is illegal in many of the US states too, some have legalized its use for medicinal purposes. While the number would be ever-changing, as of 2016 there are 17 states in the US which have legalized the use of low THC, high CBD products for medical reasons in limited situations. These states include Alabama, Georgia, Iowa, Kentucky, Florida, Mississippi, Louisiana, Missouri, North Carolina, Oklahoma, South Carolina, Wisconsin, Wyoming, Tennessee, Texas, Utah, and Virginia. It is advisable to consult your local health specialist before use.
Studies have demonstrated that CBD has a low affinity for the CB1 receptors, but even at low concentrations, CBD decreases G-protein activity (3). CB1 receptors are expressed on many glutamatergic synapses that have been implicated in seizure threshold modulation. CBD may act at CB1 receptors to inhibit glutamate release (4). Studies have shown changes in the expression of CB1 receptors during epileptogenesis and after recurrent seizures (5). CB1 receptor expression is upregulated at GABAergic synapses and shown to be downregulated at glutamatergic synapses in epilepsy, contributing to lowering seizure thresholds.
CBD may offer an option for treating different types of chronic pain. A study from the European Journal of Pain showed, using an animal model, CBD applied on the skin could help lower pain and inflammation due to arthritis. Another study demonstrated the mechanism by which CBD inhibits inflammatory and neuropathic pain, two of the most difficult types of chronic pain to treat. More study in humans is needed in this area to substantiate the claims of CBD proponents about pain control.
If you haven’t been bombarded with CBD marketing or raves about it from friends, get ready. This extract—which comes from either marijuana or its industrial cousin, hemp—is popping up everywhere. There are CBD capsules, tinctures, and liquids for vaping plus CBD-infused lotions, beauty products, snacks, coffee, and even vaginal suppositories. Already some 1,000 brands of CBD products are available in stores—and online in states that don’t have lenient cannabis laws. This is a tiny fraction of what’s to come: The CBD market is poised to exceed $22 billion by 2022, per the Chicago-based research firm Brightfield Group.
'If the Patient Information Leaflet that comes with your medication says to avoid grapefruit juice, for instance, then do not take CBD, as the same type of interaction can affect circulating blood levels of your medicine. Even if the leaflet does not mention grapefruit juice, you should still check with your doctor before taking CBD. You should also not take CBD if you are pregnant or breastfeeding.’
Topical solutions: Topical CBD products include lotions, salves and lip balms. They are meant to benefit skin, joint and muscle health, and work when they are absorbed into the skin and through the dermal layers. CBD patches are also available for topical delivery of the compound. This allows the cannabinoids to be delivered directly to your bloodstream.