Question: What is the difference between Cannabis, marijuana and hemp?

Hemp and marijuana are different names of the plant “Cannabis.” According to US Federal law, any Cannabis plant that contains less than 0.3% THC is considered hemp and anything that isn’t hemp is marijuana. Most Cannabis is now grown to produce different concentrations of THC, CBD, or a hybrid of both. Patients can find Cannabis-derived THC, Cannabis-derived CBD, and hemp-derived CBD, but not hemp-derived THC. Both THC and CBD have effects in the body. Unlike THC, CBD does not cause a euphoric “high” or an intoxicating effect.


Question: What are the side effects of medical Cannabis? Can I take it with my other medications?

Side effects that may occur right away include dizziness, sleepiness, increased heart rate, decreased alertness, and impaired coordination. These are mainly caused by the THC in Cannabis. All Cannabis users should be cautioned about driving, since they are nearly twice as likely to be involved in a motor vehicle accident than nonusers. Regular use can cause problems with memory and attention, and possibly heart and lung problems. Psychiatric disorders (eg, depression, anxiety, psychotic illness) may be worsened, especially with high potency preparations.

Because of the way it affects the body and brain, using THC- containing Cannabis with other CNS depressant drugs (eg, other pain, sleep or anxiety medications and alcohol) will likely increase sleepiness, confusion, and movement problems. Many medications can prevent the normal breakdown of THC and CBD in the body and increase or prolong their effects, including side effects. Similarly, Cannabis can prevent the normal breakdown of certain medications, increasing the likelihood that these medications will have side effects. Ask your prescriber and pharmacist if you can safely take medical Cannabis with the other medications you take.


Question: What type of Cannabis should I take? How can I find a good source for Cannabis products?

There are different methods of taking medical Cannabis. It is often inhaled, either by smoking or as vapor. It can also be taken by mouth in the form of edibles, such as brownies, liquids, or oral sprays, or applied topically to the skin. If your provider has recommended medical Cannabis, talk to him or her about which method would be best for you, and how to make sure that you get the right dose. See the inset at right for tips on various dosing methods.

Then, find a dispensary that is licensed by your state. Many states have a government website that provides a list of licensed dispensaries meeting the state’s Cannabis regulations (start at for an overall map). Once you find a dispensary where you can purchase your products, look for a certificate of analysis for the product you plan to try by searching the batch test number. The certificate will provide information about the product’s cannabinoid content and the presence of toxins such as pesticides and heavy metals.

Unfortunately, each state has its own requirements for testing and no standardized procedure exists. This means the results for the product may vary, depending on which lab processed it. You can’t be sure of the amount or the strength of the marijuana you are getting, so you need to be careful about the amount you use until you find the right dose.

Start with a low dose and slowly increase it to the dose that is most effective for your pain. You may need to try different formulations as well as different amounts of THC and CBD combined.

There are more studies supporting the effectiveness of THC for pain relief than there are for CBD. A reasonable starting dose of THC in a healthy individual who has never used Cannabis before is 1-2 mg. An effective CBD starting dose for chronic pain isn’t known. Some experts suggest starting CBD at 5 mg twice daily.

Discuss the use of any Cannabis product with your primary healthcare provider.


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