Learning About Medical Marijuana

What is medical marijuana?

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.

The two most active chemicals in marijuana are THC and CBD. THC affects how you think, act, and feel. It can make you feel very happy or "high." CBD can help you feel relaxed without the "high." And it may reduce pain and other symptoms.

There are many types, or strains, of marijuana. Each strain has specific THC-to-CBD ratios. Because of this, some strains have different kinds of effects than others. For example, if a strain of marijuana has a higher ratio of THC to CBD, it's more likely to affect your judgment, coordination, and decision making. Your doctor may be able to tell you about the different strains you can try for your health problem and the effects they might have.

Is medical marijuana helpful and safe?

Experts don't agree on how safe marijuana is or how well it works. Some don't recommend marijuana because it's not FDA-approved. It may impair judgment, and the smoke can harm your lungs. Others recommend it because it may relieve symptoms like pain and nausea when medicines have unwanted side effects or don't work.

What is it used for?

Medical marijuana may help relieve symptoms of some health problems. These may include:

• Nausea and vomiting from chemotherapy (chemo) for cancer.
• Low appetite and weight loss in people who have AIDS.
• Muscle stiffness for multiple sclerosis.
• Seizures for some types of epilepsy.
• Chronic or nerve pain.

The active chemicals in marijuana—THC and CBD—are used in some medicines to treat nausea, low appetite, and other health problems.

The U.S. Food and Drug Administration (FDA) has approved two medicines that have THC. They are:

• Dronabinol (Marinol). This is used to increase appetite in some people who have AIDS. And it's used to treat nausea in some people who get chemo for cancer.
• Nabilone (Cesamet). This is used to treat nausea in some people who get chemo.

The FDA has approved a medicine that has CBD. Epidiolex is an oil extract. It helps reduce seizures in two types of epilepsy—Lennox-Gastaut syndrome and Dravet syndrome.

How is medical marijuana used?

People can smoke medical marijuana as a dried plant or inhale it as a vapor. They can brew it into tea, spray it under the tongue, or apply it to the skin. Or they can eat it in prepared or homemade foods (edibles). And some people can take it as a pill.

How soon will you feel the effects?

How soon and how long you may feel the effects of medical marijuana depends on things like how you took it.

For example, when you smoke marijuana, you can usually feel the effects within seconds after you inhale it. But when you eat it, you may not feel the effects for up to 90 minutes. Since the effects aren't felt right away, people may think they need more and use too much. To avoid this, start with small amounts until you know how edibles affect you. Or follow your doctor's instructions on how much to use.

How much marijuana you've used and how long you've been taking it can also affect how your body responds to it.

You may be affected for hours after you use it.

What are the side effects?

Marijuana may cause a dry mouth, red eyes, and a faster heart rate. It may make you feel dizzy, drowsy, or anxious, or have paranoid thoughts. And it may make you feel sick to your stomach or vomit.

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.