• Reaching Families Project

    Online Support for People Who Care About Someone with a Mental Illness

Medication Interactions - What You May Not Know

Moderator: AndrewBCSS

Forum rules
Postings here are publicly visible and searchable with search engines. If you would like more privacy, you can post in the private forum instead. Please click here for more resources including in person support groups, newsletters and referral information.
Regular Poster
Posts: 14
Joined: 22 Jun 2017
Relationship: Friend
gender: female
Region: Lower Mainland BC

Medication Interactions - What You May Not Know

Unread postby Jean » 27 Mar 2019

Did you know that grapefruit, nicotine, cannabis and St. John’s Wort can have unexpected results on medication use and their effectiveness? These are only a few of the commonly consumed items that can have unexpected consequences when mixed with medications. When using medication, it is important to ask one’s health care provider about that particular medication and learn about all the potential side effects and how it may interact with other medication, over the counter drugs, vitamins and naturopathic remedies. These interactions may alter or interfere with the effectiveness or perceived effectiveness of prescribed medications, which can lead to unintentional drug interference and possible overdoses.

Grapefruit: Some fruit juices and fruits interact with medications causing adverse outcomes. One example is grapefruit. Grapefruit binds to an intestinal tract enzyme that inhibits how medication is absorbed. This means that if grapefruit or grapefruit juice is consumed close to when medication is administered, it may seem like the medication is ineffective. Some people then increase the dosage, but when the effects of the grapefruit juice wear off, this can lead to a medication overdose. One glass of grapefruit juice can have significant interactions with some medications, even 24 hours after consuming.

Nicotine: Nicotine consumption can highly affect absorption levels for medications, specifically psychotropic drugs (drugs that affect a person’s mental state). With smoking, the concentration of medication in the blood decreases and the effectiveness of these medications may be reduced. This can result in an unnecessary dosage increase. However, abruptly quitting smoking can also affect medication. Cigarette smoking induces the activity of human cytochromes, which metabolize drugs such as clozapine, olanzapine and methadone. When a person suddenly stops consuming nicotine, the risk of adverse drug reactions increases, because a person is no longer metabolizing the drugs so quickly.

Cannabis: Metabolic and pharmacodynamic interactions may exist between medical cannabis and other pharmaceuticals. For medications that have effects similar to those of cannabis, using cannabis may enhance these effects. For example, when cannabis (which can cause drowsiness) is used along with prescribed medications that cause drowsiness, this can intensify the effects of the medication. Since there is not a significant amount of research on drug interactions and cannabis use, experts encourage individuals to discuss the medications they are taking with a health physician to avoid potential negative drug interactions.

St. John’s Wort: St. John’s Wort is known to potentially alleviate symptoms such as anxiety and depression. However, research has shown that consuming St. John’s Wort can decrease blood concentration of some medications, making them less effective.

These are just a few of the more common drug interactions that exist with common over-the-counter medications and naturopathic treatments.

For additional information, consult with a health professional, including a pharmacist or psychopharmacologist, and always consult them before engaging in various treatments.


Return to “Family and Friends of Persons with a Mental Illness (searchable)”