medical marijuana

Medically Reviewed on 7/20/2022

Generic Name: medical marijuana

Brand and Other Names: Cannabis, Ganja, Hash, Hashish, Hemp, Mary Jane, Pot, Reefer, Weed

Drug Class: Herbals

What is medical marijuana, and what is it used for?

Marijuana, also known as cannabis, is the third most commonly used psychoactive substance world over, after alcohol and tobacco.

Marijuana is derived from dried plant parts such as leaves, stems, and flower buds of the Cannabis sativa or Cannabis indica plants. Marijuana is best known for its euphoric effects and recreational use. Medical marijuana refers to the use of marijuana in the treatment of certain medical conditions including for pain relief, however, medical use is still much debated and remains controversial.

Marijuana has been cultivated and used for medicinal purposes for thousands of years in China. Marijuana has been historically grown and used in India, Nepal, and Persia and eventually found its way to virtually all over the world, including Africa, Afghanistan, Mexico, U.S., and Australia. More than 500 compounds have been isolated in marijuana and about 100 of them are compounds known as cannabinoids.

Though marijuana has hundreds of compounds, two cannabinoids, tetrahydrocannabinol (THC) and cannabidiol (CBD) are of the most interest for therapeutic and recreational use. THC is the psychoactive compound in marijuana and CBD is a non-psychoactive compound and the two compounds are believed to be responsible for most of marijuana’s medical benefits.

The human body has an endocannabinoid system, a complex nerve signaling system that maintains the equilibrium (homeostasis) of all body systems. The endocannabinoid system works by releasing cannabinoid-like substances which activate two types of cannabinoid receptors (CB1 and CB2) found in the nervous system and all over the body. Endocannabinoids also activate many other types of receptors in the brain and body. Deficiencies in the endocannabinoid system is believed to be implicated in many diseases.

The cannabis plant cannabinoids (phytocannabinoids) THC and CBD exert their effects by binding to endocannabinoid and other receptors. In addition to psychoactive effects, THC and CBD also play a role in the release of various neurotransmitters in the brain including serotonin, dopamine, and norepinephrine.

The potential therapeutic uses for medical marijuana include:

Limited studies show medical marijuana may relieve symptoms in certain conditions including:


  • Do not use medical marijuana if you are hypersensitive to marijuana.
  • Do not use medical marijuana concurrently with dronabinol, a cannabis derived drug.
  • Marijuana has a high potential for abuse, addiction, dependence, and tolerance. Use with extreme caution in patients with a history of substance abuse or psychiatric disorders.
  • Use medical marijuana with caution in patients with following conditions:
  • Use with caution in elderly patients.
  • Avoid concurrent use with central nervous system (CNS) depressants including barbiturates, ethanol, anxiolytics, sedatives, hypnotics, sedating H1-blockers, selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs). May potentiate CNS depression.
  • Use of marijuana with sedating anticholinergic drugs may result in additive effects of tachycardia and drowsiness.
  • Marijuana may inhibit liver enzymes that metabolize drugs and increase the concentration of drugs normally broken down by the liver.


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What are the side effects of medical marijuana?

Common side effects of medical marijuana include:

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

What are the dosages of medical marijuana?

Analgesia, Antiemetic, Appetite Stimulant, Glaucoma

Dosing of marijuana preparations is highly dependent on a variety of factors (e.g., growing and harvesting conditions, plant parts isolated)

No standard guidelines exist for dosage ranges


  • Tincture: 5-15 drops or 1-3 drops of fluid extract


  • 1-3 grains (65-195 mg) cannabis for smoking
  • Potency highly variable
  • Drug deteriorates rapidly


  • Marijuana has a high potential for abuse and addiction, with increased risk for overdose. Chronic use can lead to dependence and tolerance, and withdrawal symptoms upon discontinuation.
  • Marijuana overdose may initially produce euphoria, perception alterations such as time and spatial distortion, intensification of ordinary sensory experiences, and motor impairment. Other symptoms of overdose include high anxiety, panic attack, rapid heart rate, respiratory depression, difficulty conversing, poor coordination, high or low blood pressure, nausea and vomiting, extreme confusion and memory problems, paranoia and hallucinations.
  • Marijuana overdose is treated with symptomatic and supportive care.

What drugs interact with medical marijuana?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

  • Severe interactions of marijuana include:
  • Marijuana has serious interactions with at least 21 different drugs.
  • Marijuana has moderate interactions with at least 286 different drugs.
  • Marijuana has mild interactions with at least 84 different drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.


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Pregnancy and breastfeeding

  • Marijuana use during pregnancy may affect fetal development, cause low birth weight, preterm birth or stillbirth, or lead to requirement of intensive care for the newborn. A Children’s Cancer Study Group reported 10-fold increase in childhood acute nonlymphoblastic leukemia (ANLL) with maternal use of marijuana. Avoid marijuana if you are pregnant or planning to become pregnant.
  • Marijuana compound THC is reported to be secreted in breast milk and there is insufficient information on the safety of marijuana use by nursing mothers and the effects on breastfed babies. Avoid marijuana use if you are breastfeeding.

What else should I know about medical marijuana?

  • The United States (US) Drug Enforcement Administration (DEA) classifies marijuana as a Schedule I substance under the Controlled Substances Act (CSA). Schedule I drugs are recognized as having a high potential for abuse with insufficient evidence for safety and efficacy with no currently accepted medical use for treatment in the US.
  • Marijuana is not approved by the US Food and Drug Administration (FDA) for medical use in the US and remains classified as an illicit drug by the DEA. However, 33 states and the District of Columbia have adopted individual State Medical Marijuana Laws.
  • In October of 2009, the US Justice Department announced that it will no longer enforce federal drug laws on persons who use marijuana for medicinal purposes, or their sanctioned suppliers, as long as state laws are followed. The conditions medical marijuana can treat varies from state to state.
  • The most common conditions medical marijuana can legally be used for include:
  • Take medical marijuana exactly as prescribed.
  • Nonpharmaceutical preparations may be contaminated with fungus which may be hazardous to patients with compromised immune systems. Exercise caution.
  • Avoid engaging in hazardous activities such as driving or operating heavy machinery while using medical marijuana.
  • Avoid alcohol and other drugs that can depress the central nervous system while using medical marijuana.
  • Store medical marijuana safely out of reach of children in a safe place not accessible to others, including visitors.
  • In case of overdose, seek immediate medical help or contact Poison Control.

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Medical marijuana refers to the use of marijuana in the treatment of certain medical conditions including for pain relief, nausea, reducing intraocular pressure in glaucoma, and stimulating appetite. Marijuana has a high potential for abuse, addiction, dependence, and tolerance. Common side effects of medical marijuana include physical, dizziness, drowsiness (somnolence), impaired coordination and balance, fatigue, high or low blood pressure (hypertension or hypotension), rapid heart rate (tachycardia), flushing, fainting (syncope), dry mouth (xerostomia), oral thrush (candidiasis), nausea, vomiting, diarrhea, constipation, taste perversion (dysgeusia), tooth discoloration, and others. Do not take if pregnant or breastfeeding.

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Medically Reviewed on 7/20/2022