Many states have passed legislation to legalize the use of medical marijuana in humans. There are also a variety of other marijuana-like products that are becoming more easily-accessible. The recent increase in humans seeking alternative therapies for chronic pain and other conditions has led to questions about the use of these therapies in pets. Here’s what you need to know.
Cannabinoids are chemicals produced by the Cannabis plant. The most well-known of these chemicals is THC, the psychoactive agent in marijuana that causes a “high”. Marijuana and hemp are both variations of the Cannabis plant, but differ in THC concentration. While marijuana has 5-20% THC, hemp has less than 0.3% of THC and has traditionally been used for production of rope and textiles. CBD (Cannabidiol) is one of the compounds extracted from the hemp plant. It lacks the hallucinogenic effects of THC, but possesses many of the positive medicinal properties. CBD is emerging as the preferred cannabinoid for medical use.
There are endogenous (naturally occurring) cannabinoids in in the bodies of mammals. These are involved in many normal and abnormal physiologic processes (especially neuromodulation), as they bind and modulate receptors to maintain balance of normal functions. In the USA, cannabinoid drugs are approved in humans to treat anorexia, inappetence, and epilepsy. Studies in humans and rats suggest treatment benefits for anxiety, seizures, tumors, nausea, pain, and inflammation. In pets, there are very limited studies published regarding the effects of CBD treatment. Efficacy in one species does not always translate to efficacy or safety in another species. Pets are not tiny humans. Clinical trials will need to be performed in dogs and cats to prove benefits and establish dosing and safety standards.
There are potential adverse effects of CBD products (referring to hemp products only, not marijuana). The cannabinoids appear to be very safe in dogs and cats. Dogs can experience ataxia (unsteadiness on their feet), but not necessarily harm. There is more risk of adverse effects with synthetic cannabinoid products or those in combination with other compounds, such as chocolate or xylitol, both of which have toxic effects in dogs. CBD is processed by the liver by enzymes (cytochrome P450 system). These enzymes can also be influenced by other drugs/medications and may cause the CBD or other medications to be broken down too quickly or slowly when used together.
There are some legal concerns with the cannabinoid products. Until recently, CBD was considered a Schedule 1 controlled substance (same as cocaine) that is defined as having “no currently accepted medical use and a high potential of abuse.” Based on this law, unless a veterinarian has a specific DEA license to work with Schedule 1 substances, they cannot distribute, dispense or posses CBD. This means that a veterinarian cannot legally dispense or prescribe CBD to a pet or patient. However, the Agriculture Improvement Act of 2018 (aka the US Farm Bill) was recently passed. One of the provisions of the bill is to exempt industrial cannabis and its derivatives (must contain less than 0.3% THC) from being labeled as Schedule 1 controlled substances. Cannabis will no longer be an illegal substance under federal law. This will potentially allow use of these products for a variety of purposes in the future. CBD products with therapeutic claims (including supplements and food additives), will still be under FDA regulation, thus will require FDA approval before they can be marketed or sold in the USA. This is the same standard process by which any other product marketed as a human or animal drug must undergo.
For now, there is limited science regarding safety, efficacy, and purity of products. There will need to be clinical trials and safety studies in order to establish reliable sources of CBD products. The FDA is taking steps to advance knowledge and protect public safety in regards to CBD products, in the interest of establishing safe and effective CBD products. In the meantime, if a pet is exposed to a cannabis product, they should be monitored closely for signs of toxicity (weakness, depression, ataxia, behavior change, seizures). If any adverse effect is noted, the pet should be examined by a veterinarian immediately. It is crucial that an owner bring in details about the specific product used and the quantity received so the pet can receive appropriate treatment.