Does cannabis interact with antidepressants or lithium?
Cannabis and antidepressants
Cannabis or marijuana can interact with tricyclic antidepressants (TCAs), such as amitriptyline, imipramine and dothiepin.
Both cannabis and TCAs can cause an abnormally fast heartbeat (tachycardia) and high blood pressure (hypertension). There’s also a risk of other side effects, such as confusion, restlessness, mood swings and hallucinations.
There’s a risk that using cannabis while you’re on any of these medicines could lead to problems such as tachycardia, even if you don’t already have a heart condition.
Little research has been done into the interaction of cannabis with other types of antidepressants, such as SSRIs.
Cannabis and lithium
Lithium is used to treat bipolar disorder, a condition where people can switch between depression and extreme excitement and agitation (mania).
There’s little evidence to suggest that people who use cannabis should normally not take lithium, but this hasn’t been properly researched.
Side effects of cannabis
It’s not clear how often cannabis itself can cause anxiety or depression, but research suggests this can happen.
It’s therefore recommended that if you’re anxious or depressed and you use cannabis regularly, you should try giving up and see if that helps.
Tachycardia, dizziness, anxiety, drowsiness, nausea and vomiting, difficulty sleeping and confusion are all possible side effects of cannabis.
These side effects can also be caused by certain antidepressants, so using cannabis at the same time can make them worse.
If you have any concerns about the medicines you’re taking, talk to your GP or pharmacist.
You can also phone NHS 111 or Talk to Frank, a friendly confidential drugs helpline, on 0300 123 6600.
- Antidepressant drugs
- Can I drink alcohol if I’m taking antidepressants?
- Medicines information
Page last reviewed: 27 March 2018
Next review due: 27 March 2021
Cannabis or marijuana is usually smoked and typically mixed with tobacco. It can interact with certain types of antidepressants, such as tricyclic antidepressants (TCAs), which share similar side effects.
How Cannabis Interacts With Mental Health Medication
Today, marijuana law is still lingering around in a grey area, despite a growing number of patients using cannabis for medicinal relief. To date, there are still no recorded deaths related to marijuana, yet it might dangerously interact with a patient’s prescribed mental health medication.
Before diving right into the potential interactions of combining cannabis with pharmaceuticals, first we should understand what’s in cannabis. Each variety or strain of marijuana contains hundreds of compounds, many of which are medicinal. The most important and abundant medicinal ingredients in cannabis are compounds called cannabinoids, with THC and CBD being the most abundant constituents. Whether psychoactive or non-psychoactive, marijuana comes in many varieties, so this is why the cause and effect needs to be carefully monitored.
EFFECTS OF MARIJUANA ON MENTAL HEALTH
For most patients, marijuana is relatively safe and can make one feel more relaxed, less stressed, and of course, happier. However, its use can also result in a range of adverse mental health effects. Some individuals are more vulnerable than others to experiencing negative effects on high doses of marijuana, especially those with a personal or family history of mental illness. There are some cases where cannabis has the potential to decrease the potency or effectiveness of other drugs. For example, one may feel overly sedated when consuming cannabis with a sedative.
Doctors prescribe medication for different mental issues to bring relief from the unpleasant symptoms that a patient may be experiencing. Continuing marijuana use while taking prescribed medications may cause unpredictable reactions and/or worsen a patient’s condition. It may also make it difficult for one’s prescribing doctor to properly diagnose. Being aware of which pharmaceutical drugs shouldn’t be taken in combination with cannabis will allow for a safer and more enjoyable experience. Below are the most common drugs people combine with marijuana.
CANNABIS INTERACTIONS WITH ANTIDEPRESSANTS
Surprisingly, despite years of investigative research between cannabis use and mental disorders, there have been few studies published that closely examine how it interacts with antidepressants. Nonetheless, today, it’s likely that newer antidepressants carry a low to moderate risk for contraindications, while older antidepressants carry a much higher risk. Those suffering from depression are usually prescribed antidepressants belonging to one of four main groups.
Selective Serotonin Reuptake Inhibitors (SSRIs):
Monoamine Oxidase Inhibitors (MAOIs):
There has been little conducted research on the effects of using marijuana while taking prescribed antidepressant medication, however, there have been reports of numerous contraindications. Symptoms include:
- Rapid heart rate
- Mental confusion
- Muscle twitching
- Gastrointestinal distress
Using marijuana while on antidepressants can be potentially dangerous, as it can intensify any or all of these side effects, making a patient’s condition even worse. This is also very similar with sedatives. Alcohol or drugs like Ativan, Valium, and other antidepressants work to produce a calming effect when interacting with the neurotransmitters in the central nervous system. The problem here is that cannabis can also have a sedative effect at different degrees of intensity, depending on cannabinoid content. Mixing cannabis with antidepressants can result in a major central nervous system depression. It’s been advised that cannabis users exercise caution when using sedative drugs, as the combination can be extremely risky.
CANNABIS INTERACTIONS WITH ANTIPSYCHOTICS
Antipsychotic medications work as tranquilisers and are most effective in treating people who have had psychotic episodes, hallucinations, and delusions associated with schizophrenia and other psychotic disorders. Some common antipsychotic medications people use include:
Cannabidiol has many therapeutic attributes as a safe and non-addictive cannabis compound, however it’s interactions may be problematic in some cases. When consumed, the way cannabidiol interacts with enzyme cytochrome P450 is pivotal; in essence, they deactivate each other. At sufficient doses, this compound consumed along with certain antipsychotics can intensify a drug and may cause increased side effects or potentially serious adverse reactions.
Marijuana alters the metabolism when interacting with drugs broken down by cytochrome P450 enzymes in the liver. These enzymes are found in certain classes of antipsychotics that function to metabolise potentially toxic compounds in the body. Unfortunately, once cannabidiol interacts with these enzymes, it prevents the proper breakdown of the drugs. This is why people with schizophrenia can experience severe depression, which may need to be treated. Users should be watchful of these symptoms:
- Excessive sedation
- Slow motor skills
- Decreased cognitive function
- Impaired driving
WHAT YOU CAN DO
Using marijuana while taking certain medications can have adverse side effects, which may cause symptoms to become more severe and difficult to manage in the long-term. Remember that medications are prescribed to make people feel better. It has been suggested by research that those who seek counseling can greatly improve their chances of giving up or cutting down their marijuana use while taking medication. If you use marijuana regularly and also take prescribed medications, or know someone who does, the following things may help:
- Be honest with your doctor: Before prescribing, make him/her aware of your marijuana use, both how frequent and how much you’re using.
- Time matters: Give your medication a chance to take effect, as it can take up to six weeks or more.
- Listen to your body: If there are any serious complications experienced when consuming prescription medication and marijuana together, seek help from a healthcare professional to determine what is best for you.
EACH PERSON IS DIFFERENT
Even if avoiding cannabis for an extended period of time may sound inconceivable to some, it may need to be given up (at least temporarily) if it poses dangerous health risks when combined with another drug. However, cannabis itself is experienced differently by each user. Consequently, adding prescriptions to the equation will more than likely cause unique reactions in people that current research can’t exactly quantify.
Marijuana is known to treat a number of diseases, but despite this, using it with prescribed medications can cause unpredictable interactions.