Marijuana is a controlled substance in the U.S. Federal law prohibits its use for any reason. Many states, however, allow medical use of marijuana to treat pain, nausea and other symptoms.By Mayo Clinic Staff
Medical marijuana — also called medical cannabis — is a term for derivatives of the Cannabis sativa plant that are used to relieve serious and chronic symptoms.
Cannabis sativa contains many active compounds, but two are of interest for medical purposes: THC (delta-9 tetrahydrocannabinol) and CBD (cannabidiol). THC is the primary ingredient in marijuana that makes people "high."
Is medical marijuana legal in the U.S.?
U.S. federal law prohibits the use of whole plant Cannabis sativa or its derivatives for any purpose. CBD derived from the hemp plant (< 0.3% THC) is legal under federal law to consume.
Many states allow THC use for medical purposes. Federal law regulating marijuana supersedes state laws. Because of this, people may still be arrested and charged with possession in states where marijuana for medical use is legal.
When is medical marijuana appropriate?
Studies report that medical cannabis has possible benefit for several conditions. State laws vary in which conditions qualify people for treatment with medical marijuana. If you're considering marijuana for medical use, check your state's regulations.
Depending on the state, you may qualify for treatment with medical marijuana if you meet certain requirements and have a qualifying condition, such as:
- Alzheimer's disease
- Amyotrophic lateral sclerosis (ALS)
- Crohn's disease
- Epilepsy and seizures
- Multiple sclerosis and muscle spasms
- Severe and chronic pain
- Severe nausea
If you are experiencing uncomfortable symptoms or side effects of medical treatment, especially pain and nausea, talk with your doctor about all your options before trying marijuana. Doctors may consider medical marijuana as an option if other treatments haven't helped.
Is medical marijuana safe?
Further study is needed to answer this question, but possible side effects of medical marijuana may include:
- Increased heart rate
- Impaired concentration and memory
- Slower reaction times
- Negative drug-to-drug interactions
- Increased risk of heart attack and stroke
- Increased appetite
- Potential for addiction
- Cyclic vomiting syndrome
- Hallucinations or mental illness
- Withdrawal symptoms
Is medical marijuana available as a prescription medicine?
The U.S. Food and Drug Administration (FDA) has approved one cannabis-derived and three cannabis-related drugs: dronabinol (Marinol, Syndros), nabilone (Cesamet) and cannabidiol (Epidiolex).
Dronabinol and nabilone can be prescribed for the treatment of nausea and vomiting caused by chemotherapy and for the treatment of anorexia associated with weight loss in people with AIDS. Cannabidiol can be prescribed for treatment of severe forms of childhood epilepsy.
What you can expect
Medical marijuana comes in a variety of forms, including:
- Oil for vaporizing
- Topical applications
- Oral solution
- Dried leaves and buds
How and where you purchase these substances legally varies among the states that allow medical use of marijuana. Once you have the product, you administer it yourself. How often you use it depends on its form and your symptoms.
Your symptom relief and side effects also will vary based upon which type you are using. The quickest effects occur with inhalation of the vaporized form. The slowest onset occurs with the pill form.
Some medical marijuana is formulated to provide symptom relief without the intoxicating, mood-altering effects associated with recreational use of marijuana.
Nov. 27, 2019
Certification and use on Mayo Clinic campuses
Arizona, Florida and Minnesota have adopted some form of the federal Right to Try Act. This law permits access to investigational treatments, including possibly marijuana, for people with life-threatening conditions who have exhausted approved treatment options. The Right to Try Act typically does not limit in-state use to in-state residents only. Statements below do not apply to Right to Try situations.
In Arizona, certifications for medical cannabis may be issued by an allopathic, osteopathic, homeopathic or naturopathic physician who has a valid Arizona license. Mayo Clinic campuses in Arizona do not dispense medical marijuana, certify people for using it, or allow its use on campus or in the hospital.
Florida law permits qualified physicians to order medical cannabis or low-THC cannabis for patients diagnosed with certain conditions. Mayo Clinic campuses in Florida do not dispense medical marijuana and do not allow its use on campus or in the hospital.
In Minnesota, a physician, physician assistant or advanced practice registered nurse certify qualifying medical conditions. Minnesota residents with qualifying conditions need to register with the Minnesota Department of Health.
Mayo Clinic practices in Minnesota may certify state residents with qualifying conditions in the Minnesota medical cannabis program. Not all Mayo Clinic health care providers will be registered for the certification process in Minnesota.
Minnesota residents with a supply of medical cannabis from the Minnesota Medical Cannabis program may continue use during their Mayo Clinic visit or hospital admission.
- Arizona Department of Health Services: Medical marijuana
- Florida Health: Office of Medical Marijuana Use
- Minnesota Department of Health: Medical cannabis
- National Conference of State Legislatures: State medical marijuana laws
See more In-depth
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