Overview

Marijuana, also called cannabis, is a drug that's made of the leaves, flowers, and buds of the cannabis plant. Medical marijuana can help treat symptoms like pain, nausea, and lack of appetite. It may be used by people who have health problems like cancer, AIDS, or multiple sclerosis.

Is medical marijuana helpful and safe?

Medical use of marijuana has been studied for decades. But experts still don't agree on how safe it is or how well it works.

Some experts don't recommend marijuana because:

• It's not approved by the U.S. Food and Drug Administration.
• It may impair your memory, judgment, and coordination. It can increase your risk of being in a car crash.
• Marijuana smoke may harm your lungs.
• There are legal drugs for pain and nausea that may work just as well.

Other experts recommend marijuana because:

• It can be a substitute for pain medicines (opioids) that have serious health risks such as overdose and death.
• It can improve appetite and relieve nausea in people who have cancer or AIDS.
• It may help relieve symptoms such as pain and muscle stiffness from multiple sclerosis.

Be sure to let your doctor know if you're using medical marijuana. If you're pregnant, it's not safe to use marijuana.

What are the risks?

Marijuana can interact with other medicines. It can be dangerous if you use it with medicines that make you sleepy or control your mood. These include sedatives, anxiety drugs, antidepressants, and opioids. And it can be dangerous to use marijuana with alcohol, tobacco, and illegal drugs.

Marijuana raises your chance of bleeding if you're on blood thinners. And it can affect your blood pressure. So use caution if you take blood pressure medicine.

Talk to your doctor about other medicines you use before you try marijuana. And talk to your doctor about any personal or family history of substance use disorders or mental health problems. Using marijuana may make these problems worse.

Marijuana may affect your judgment, memory, and concentration. And it may affect your coordination and decision-making. Do not drive or operate machinery after you use marijuana. Talk with your doctor about when it's safe to drive.

Long-term use of marijuana may increase your risk for severe nausea and vomiting. This is called cannabinoid hyperemesis syndrome, or CHS. People who have CHS may feel very thirsty. They may have belly pain and diarrhea. They may vomit more than 20 times a day. Bouts of vomiting may last more than 24 hours.

Some people who use marijuana may develop cannabis use disorder. This can range from mild to severe. People who have it may find it hard to control their use. And they may keep using marijuana even though it's having harmful effects on their life.

The risk of this disorder is higher in people who:

• Start using marijuana when they're young.
• Use it every day.
• Have other substance use disorders and mental health problems.

People who use marijuana often and then quit may have withdrawal symptoms. Symptoms include anxiety, trouble sleeping, and intense cravings for the drug.

If you smoke marijuana, the smoke could damage your lungs. It may make you cough or wheeze. And it may cause lung infections like bronchitis.

If you use medical marijuana and are pregnant (or think you might be) or you are breastfeeding, talk to your doctor. It can affect your baby's development.

How do you use medical marijuana?

People can smoke medical marijuana. They can also:

• Brew it into tea.
• Inhale it as a vapor.
• Spray it under the tongue.
• Apply it to the skin.
• Eat it in prepared or homemade foods.

There are many types, or strains, of marijuana. Some strains are much stronger or have different kinds of effects than others. Talk to your health care provider or to the staff at the dispensary (sometimes called a budtender). They can tell you about the different strains you can try for your condition.

You may feel the effects for hours after you use the drug. How soon you feel them and how long they last can depend on many things. These include:

• How much of the drug you used.
• How you took it.
• How long you've been taking it.
• How your body responds to it.

Some people use medical marijuana after trying other common medicines.

Are there alternatives to medical marijuana?

Doctors can prescribe two legal alternatives to medical marijuana. They are dronabinol (Marinol) and nabilone (Cesamet). Both of these drugs contain a man-made form of THC, the main chemical in marijuana.

Nabilone is used to relieve nausea and vomiting caused by cancer chemotherapy. Dronabinol also can relieve this kind of nausea and vomiting. It may also improve the appetite of people who have AIDS. Both of these drugs can be used to relieve pain and spasticity from multiple sclerosis. Both drugs come in pill form.

Talk to your doctor if you think these medicines might help relieve your symptoms.

What is synthetic marijuana?

Synthetic marijuana is made of dried plant material that is treated with chemicals that produce effects like marijuana's effects. It is sold in the form of incense under many names, such as K2 or Spice. The labels often claim that these products are "safe" or "natural." But in fact, the active chemicals are created in a lab. And they have not been tested for safety.

But young people often try these products because they are easy to buy and they may not be detected by drug tests.

People think that using these drugs will make them feel the same as when they use marijuana. But these drugs can be stronger than marijuana. And the effects are hard to predict. That's because the type and strength of the chemicals used are often unknown. Some people have reported severe symptoms, such as:

• Fast heart rate and high blood pressure.
• Vomiting.
• Feeling agitated or confused.
• Feeling like others want to harm them (paranoia), or seeing or hearing things that aren't there (hallucinations).