7 Common Medical Cannabis Side Effects: What to Expect
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Clark Harrison
Medical Cannabis Side Effects
Medical cannabis is widely used for managing chronic pain and other conditions, but it can come with side effects. Here’s a quick overview of the most common ones and how to manage them:
Dry Mouth: Stay hydrated, chew sugar-free gum, and avoid caffeine or alcohol.
Dizziness: Change positions slowly, stay hydrated, and limit alcohol or nicotine.
Changes in Hunger: THC can increase appetite; opt for high-CBD or appetite-suppressing strains if needed.
Memory and Focus Changes: Use balanced THC:CBD strains and avoid driving or critical tasks.
Sleepiness: Adjust doses and timing to minimize daytime fatigue.
Increased Anxiety: Choose low-THC, high-CBD strains and avoid high-THC concentrates.
Medicine Interactions: Consult your doctor to avoid adverse reactions with other medications.
Quick Tip: Always start with a low dose, track side effects, and communicate with your healthcare provider to tailor your treatment plan.
Side effects from Medical Cannabis
1. Dry Mouth
Dry mouth, also called xerostomia or “cottonmouth”, is a common side effect for medical cannabis users. Knowing how to manage it can make your experience more comfortable.
Why Does Dry Mouth Happen?
Cannabinoids like THC and CBD interact with brain receptors that control saliva production. They particularly affect the submandibular glands, which are responsible for producing most of your saliva (about 60–67%). This interaction disrupts the signals responsible for saliva flow, leading to dryness.
Tips for Managing Dry Mouth
Around 65% of users report experiencing dry mouth. Here are some ways to manage it:
Sip on ice-cold water throughout the day to keep your mouth moist.
Chew sugar-free gum or suck on lozenges with flavors like citrus, cinnamon, or mint.
Use over-the-counter oral moisturizers, such as sprays or gels.
Apply lip balm frequently to prevent cracked lips.
Run a humidifier in your bedroom while you sleep.
Breathe through your nose instead of your mouth whenever possible.
What to Avoid
Certain items can worsen dry mouth or make it more uncomfortable:
Items
Why It Matters
Caffeine
Can cause dehydration
Alcohol
Makes dryness worse
Carbonated drinks
May irritate mouth tissues
Spicy or salty foods
Can heighten discomfort
Sugary snacks
Increases the risk of cavities
For ongoing relief, maintain good oral hygiene by brushing twice daily with fluoride toothpaste and using an alcohol-free mouthwash. If the issue persists or becomes severe, speak with your healthcare provider. They may suggest adjusting your cannabis dosage or exploring different methods of consumption.
Now, let’s move on to another common side effect.
2. Dizziness
After discussing dry mouth, let’s focus on dizziness – another frequent side effect of medical cannabis treatment.
Causes of Dizziness
Medical cannabis can impact blood pressure and blood flow, which often leads to dizziness. Here are the main factors contributing to this:
Factor
Effect
Blood Pressure Changes
May result in postural hypotension when standing
Cerebral Blood Velocity
Can decrease in upright positions
Heart Rate
Increases by 20–100% for 2–3 hours
Position Changes
Quick movements can trigger dizziness
Research shows that 60% of participants experienced moderate to severe dizziness while standing after consuming cannabis, whereas no such effects were observed with a placebo. Severe dizziness was linked to noticeable drops in blood pressure and cerebral blood velocity.
Preventing Dizziness
Here are some tips to help reduce dizziness during medical cannabis use:
Change positions gradually.
Stay hydrated and limit caffeine, alcohol, and nicotine.
Avoid sudden or jerky movements.
If dizziness occurs, sit or lie down until it passes. Focus on a fixed point and breathe deeply. For severe or ongoing dizziness, consult your healthcare provider – they may need to adjust your dose or recommend a different treatment plan.
Up next: managing other common side effects. Stay tuned.
3. Changes in Hunger
Effects on Appetite
THC influences hunger by interacting with CB1 receptors, setting off processes that increase appetite. Here’s how it works:
Mechanism
Impact on Appetite
Ghrelin Release
Boosts production of the “hunger hormone”
Dopamine/Serotonin
Heightens food enjoyment
Brain Signaling
Prompts hunger, even without a caloric need
CBD Impact
May indirectly increase appetite by reducing anxiety
Studies back this up. For example, Marinol has been shown to increase appetite by nearly 40%. A 2021 study also found that medical cannabis helped cancer patients with cancer-related cachexia improve their appetite.
Understanding these processes can help you better manage hunger while using cannabis.
Controlling Food Intake
Keeping your appetite in check is crucial when incorporating cannabis into your routine. Here are some practical strategies:
Strategy
Tips for Implementation
Strain Selection
Opt for high-CBD or high-THCV strains to curb hunger
Timing
Eat balanced meals before cannabis use
Environment
Keep healthy snacks handy and remove unhealthy temptations
Hydration
Have flavored water available to curb cravings
Certain strains can help reduce appetite stimulation. High-THCV strains, like Durban Poison, are known for their appetite-suppressing effects. Other strains worth considering include:
“The neurons we thought were responsible for shutting down eating were suddenly being activated and promoting hunger, even when you are full. It [cannabis] fools the brain’s central feeding system”.
Consult with your healthcare provider to find the right strains and dosages that suit your dietary needs and goals.
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4. Memory and Focus Changes
Understanding how cannabis affects memory and focus can help you manage these challenges effectively during treatment.
Memory Effects
Using medical cannabis, especially in high doses or over a long period, can affect short-term memory and attention. Studies indicate that 63% of heavy lifetime cannabis users show decreased brain activity during tasks involving working memory. This can impact areas like working memory, decision-making, coordination, and recalling past events.
Safety Guidelines
To ensure safety, avoid driving or using machinery for at least 8 hours after consuming cannabis. Always adhere to any activity restrictions provided by your healthcare professional.
Maintaining Focus
To minimize cognitive effects, try strains with a balanced THC:CBD ratio and terpenes that may support focus. Start with small doses, use cannabis during non-critical times, and explore micro-dosing as a way to manage cognitive impacts more precisely.
“People need to be aware of their relationship with cannabis since abstaining cold turkey could disrupt their cognition as well. For example, heavy users may need to be more cautious.”
Because everyone reacts differently, work closely with your healthcare provider to customize your approach.
Next, we’ll explore how cannabis can cause sleepiness and what that means for your daily activities.
5. Sleepiness
Feeling drowsy is a well-known side effect of medical cannabis, impacting about 4.4% of users.
Why Does Cannabis Make You Sleepy?
When CBD and THC enter your bloodstream, they influence your sleep-wake cycle. Research explains: “Cannabinoids elevate the levels of the sleep-promoting chemical adenosine while suppressing the brain’s arousal system”.
Several factors determine how sleepy you might feel:
Strain type: Indica strains are more likely to cause drowsiness than Sativa varieties.
Consumption method: Smoking typically leads to quicker effects compared to edibles.
Dosage: Higher doses often result in increased drowsiness.
Individual biology: Everyone reacts to cannabis differently based on their unique body chemistry.
Managing Daytime Fatigue
Although 85% of medical cannabis users report better sleep, staying alert during the day can still be a challenge. Here’s how to strike a balance:
Begin with a low dose and slowly increase as needed.
Schedule doses to fit your daily routine.
Opt for products with balanced THC-to-CBD ratios.
Incorporate light physical activity to help fight fatigue.
“In general, CBD tends to help people fall asleep faster and potentially stay asleep longer.”
– Adam Perlman, M.D., Integrative and Functional Medicine Expert
Adjusting your consumption timing can also help you enjoy restful nights without feeling sluggish during the day:
Time of Day
Suggested Approach
Likely Outcome
Morning
Use low-potency THC or balanced THC:CBD products
Minimized morning grogginess
Afternoon
Choose non-smoking methods with controlled doses
Sustained alertness
Evening
Stick to prescribed doses
Enhanced sleep quality
6. Increased Anxiety
Some people using medical cannabis might notice heightened anxiety as a side effect. Knowing why this happens and how to address it can help make treatment more effective.
What Triggers Anxiety?
THC has a biphasic effect, meaning it can calm at low doses but may heighten anxiety at higher doses. Common triggers include:
THC concentration: Many modern cannabis strains contain 15–20% THC, with some going as high as 35%. Higher THC levels can increase anxiety risks.
Product type: Concentrates like wax or shatter often have THC levels between 60–90%, which may amplify anxious feelings.
Individual sensitivity: Personal factors, such as a family history of mental health conditions, can influence how someone reacts.
How to Manage Anxiety
Choosing the right products and using them carefully can help reduce anxiety related to cannabis:
Approach
Recommendation
Outcome
THC Content
Opt for low-THC strains
Less risk of anxiety
CBD Ratio
Pick high-CBD options
Balances THC’s effects
Consumption Method
Start with oils or tinctures
Easier to control dosage
Timing
Use during calm periods
Avoids anxiety triggers
Strains known to help with anxiety include Mazar, Romulan, LA Confidential, Northern Light, and Cheese.
When to Seek Help
If anxiety persists while using medical cannabis:
Track your symptoms to identify which products might be causing issues.
Consider switching to high-CBD strains like Remedy, ACDC, or Charlotte’s Web.
Talk to your healthcare provider to adjust your treatment plan.
Daniel Lantela, co-founder of Whistler Therapeutics, says, “Everyone is different, so keep trying different strains until you find one that works best for you”.
Certain terpenes, such as myrcene, pinene, and caryophyllene, may also help promote relaxation. On the flip side, avoid strains like Green Crack, Modified Bananas, and GMO Cookies, which are more likely to increase anxiety.
Keep exploring ways to fine-tune your treatment for the best results.
7. Medicine Interactions
When using medical cannabis, it’s important to consider how it might interact with your current medications. Cannabis, particularly THC and CBD, can interact with many prescription drugs because they share liver enzyme pathways.
Known Drug Interactions
THC interacts with around 400 medications, while CBD has interactions with over 540. These interactions usually occur through liver enzymes responsible for metabolizing both cannabis and other drugs.
Here are some common medications that may interact with cannabis:
Medication Type
Examples
Potential Effects
Sedatives
Ambien, Lunesta
Increased drowsiness
Anti-anxiety drugs
Xanax, Valium
Heightened drowsiness, confusion
Pain medications
Codeine, Percocet
Increased drowsiness
Blood thinners
Coumadin, Plavix
Higher risk of bleeding
Anticonvulsants
Tegretol, Depakene
Fluctuating drug levels
For example, research indicates that smoking cannabis can speed up the clearance of certain medications, such as theophylline, by 40%.
“THC can cause impairment, no matter how it is used, and marijuana can be dangerous when combined with prescribed medications. We want everyone to be aware about possible drug interactions so that they can protect themselves and their loved ones from harm.”
– Seung Oh, PharmD, Pharmacy Supervisor at Sharp Rees-Stealy Santee Medical Center
Medication Safety
To minimize risks when combining cannabis with other medications:
Talk to your doctor or pharmacist before using cannabis alongside other drugs.
Watch for unusual symptoms, especially when adjusting doses or adding new medications.
Start with a low dose and increase gradually, particularly when using CBD with drugs like valproate. Regular liver function tests may also be needed.
Keep emergency contacts handy in case of adverse reactions.
Older adults should be especially cautious, as they often take multiple medications and may be more sensitive to interactions. Since many cannabis-drug interactions are theoretical or based on limited reports, staying in close communication with healthcare providers is key to safe and effective treatment.
Next Steps
Summary
Dealing with medical cannabis side effects requires active involvement and careful planning. Keeping a detailed record of any side effects can help your doctor fine-tune your treatment plan.
Here are some practical steps to guide your treatment:
Treatment Aspect
Action Steps
Benefits
Consult Your Doctor
Schedule regular check-ins and discuss any side effects
Allows for timely adjustments
Medication Management
Track drug interactions and maintain an updated list
Reduces the risk of adverse reactions
Support Resources
Reach out to SAMHSA‘s National Helpline (1-800-662-HELP)
These steps build on earlier points about managing side effects and equip you to take charge of your treatment journey.
“Your best bet is to ask your doctor about the benefits and risks associated with any options you are considering so you can determine what makes the most sense for your specific symptoms and circumstances.” – Lisa D. Ellis
For tailored care and simplified management, Elios Clinics offers specialized medical cannabis treatments along with thorough side effect management.
Their services include:
Video consultations with GMC-approved doctors to adjust your treatment plan.
Monthly prescriptions with next-day medication delivery.
A patient dashboard to help you track prescriptions and appointments.
Regular follow-ups to monitor and address side effects effectively.
Elios Clinics also provides flexible subscription plans starting at $20 per month, which include quarterly follow-up appointments and adjustments to your treatment plan.
For tailored care and simplified management, Elios Clinics offers specialized medical cannabis treatments along with thorough side effect management.
Their services include:
