Products containing cannabidiol (CBD) seem to be all the rage these days, promising relief from a wide range of maladies, from insomnia and hot flashes to chronic pain and seizures. Some of these claims have merit to them, while some of them are just hype. But it won’t hurt to try, right? Well, not so fast. CBD is a biologically active compound, and as such, it may also have unintended consequences. These include known side effects of CBD, but also unintended interactions with supplements, herbal products, and over-the-counter (OTC) and prescription medications.
Doubling up on side effects
While generally considered safe, CBD may cause drowsiness, lightheadedness, nausea, diarrhea, dry mouth, and, in rare instances, damage to the liver. Taking CBD with other medications that have similar side effects may increase the risk of unwanted symptoms or toxicity. In other words, taking CBD at the same time with OTC or prescription medications and substances that cause sleepiness, such as opioids, benzodiazepines (such as Xanax or Ativan), antipsychotics, antidepressants, antihistamines (such as Benadryl), or alcohol may lead to increased sleepiness, fatigue, and possibly accidental falls and accidents when driving. Increased sedation and tiredness may also happen when using certain herbal supplements, such as kava, melatonin, and St. John’s wort. Taking CBD with stimulants (such as Adderall) may lead to decreased appetite, while taking it with the diabetes drug metformin or certain heartburn drugs (such as Prilosec) may increase the risk of diarrhea.
CBD can alter the effects of other drugs
Many drugs are broken down by enzymes in the liver, and CBD may compete for or interfere with these enzymes, leading to too much or not enough of the drug in the body, called altered concentration. The altered concentration, in turn, may lead to the medication not working, or an increased risk of side effects. Such drug interactions are usually hard to predict but can cause unpleasant and sometimes serious problems.
Researchers from Penn State College of Medicine evaluated existing information on five prescription CBD and delta-9-tetrahydrocannabinol (THC) cannabinoid medications: antinausea medications used during cancer treatment (Marinol, Syndros, Cesamet); a medication used primarily for muscle spasms in multiple sclerosis (Sativex, which is not currently available in the US, but available in other countries); and an antiseizure medication (Epidiolex). Overall, the researchers identified 139 medications that may be affected by cannabinoids. This list was further narrowed to 57 medications, for which altered concentration can be dangerous. The list contains a variety of drugs from heart medications to antibiotics, although not all the drugs on the list may be affected by CBD-only products (some are only affected by THC). Potentially serious drug interactions with CBD included
- a common blood thinner, warfarin
- a heart rhythm medication, amiodarone
- a thyroid medication, levothyroxine
- several medications for seizure, including clobazam, lamotrigine, and valproate.
The researchers further warned that while the list may be used as a starting point to identify potential drug interactions with marijuana or CBD oil, plant-derived cannabinoid products may deliver highly variable cannabinoid concentrations (unlike the FDA-regulated prescription cannabinoid medications previously mentioned), and may contain many other compounds that can increase the risk of unintended drug interactions.
Does the form of CBD matter?
Absolutely. Inhaled CBD gets into the blood the fastest, reaching high concentration within 30 minutes and increasing the risk of acute side effects. Edibles require longer time to absorb and are less likely to produce a high concentration peak, although they may eventually reach high enough levels to cause an issue or interact with other medications. Topical formulations, such as creams and lotions, may not absorb and get into the blood in sufficient amount to interact with other medications, although there is very little information on how much of CBD gets into the blood eventually. All of this is further complicated by the fact that none of these products are regulated or checked for purity, concentration, or safety.
The bottom line: Talk to your doctor or pharmacist if using or considering CBD
CBD has the potential to interact with many other products, including over-the-counter medications, herbal products, and prescription medications. Some medications should never be taken with CBD; the use of other medications may need to be modified or reduced to prevent serious issues. The consequences of drug interactions also depend on many other factors, including the dose of CBD, the dose of another medication, and a person’s underlying health condition. Older adults are more susceptible to drug interactions because they often take multiple medications, and because of age-related physiological changes that affect how our bodies process medications.
People considering or taking CBD products should always mention their use to their doctor, particularly if they are taking other medications or have underlying medical conditions, such as liver disease, kidney disease, epilepsy, heart issues, a weakened immune system, or are on medications that can weaken the immune system (such as cancer medications). A pharmacist is a great resource to help you learn about a potential interaction with a supplement, an herbal product (many of which have their own drug interactions), or an over-the-counter or prescription medication. Don’t assume that just because something is natural, it is safe and trying it won’t hurt. It very well might.
Bible verses for today’s meditation and inspiration: Matthew E. McLaren
Your beauty should not come from outward adornment, such as elaborate hairstyles and the wearing of gold jewelry or fine clothes. Rather, it should be that of your inner self, the unfading beauty of a gentle and quiet spirit, which is of great worth in God’s sight. 1 Peter 3:3-4 NIV
Above all else, guard your heart, for everything you do flows from it. Proverbs 4:23 NIV
As water reflects the face, so one’s life reflects the heart. Proverbs 27:19 NIV
May he give you the desire of your heart and make all your plans succeed. Psalm 20:4 NIV
The heart is deceitful above all things and beyond cure. Who can understand it? “I the Lord search the heart and examine the mind, to reward each person according to their conduct, according to what their deeds deserve.” Jeremiah 17:9-10 NIV
You will seek me and find me when you seek me with all your heart. Jeremiah 29:13 NIV
Let love and faithfulness never leave you; bind them around your neck, write them on the tablet of your heart. Then you will win favor and a good name in the sight of God and man. Proverbs 3:3-4 NIV
Trust in the Lord with all your heart and lean not on your own understanding; in all your ways submit to him, and he will make your paths straight. Proverbs 3:5-6 | NIV
Create in me a pure heart, O God, and renew a steadfast spirit within me. Psalm 51:10 NIV
But the Lord said to Samuel, “Do not consider his appearance or his height, for I have rejected him. The Lord does not look at the things people look at. People look at the outward appearance, but the Lord looks at the heart.” 1 Samuel 16:7 NIV
Jesus replied: ‘Love the Lord your God with all your heart and with all your soul and with all your mind.’ Matthew 22:37 NIV
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