Tricyclic antidepressants such as amitriptyline, amoxapine, doxepin, and nortriptyline
Because it may block the effects of the enzyme monoamine oxidase, passion flower may possibly increase the effects and the risk of side effects from prescription drugs that also interfere with monoamine oxidase. These drugs, known as monoamine oxidase inhibitors (MAOIs), include:
- Marplan
- Nardil
- selegiline (Eldepryl)
- tranylcypromine (Parnate)
Selegiline (Eldepryl) and rasagiline (Azilect), drugs which are related to the MAOI antidepressants and which are used to treat Parkinson's disease, also should not be taken with passion flower.
Non-prescription Drugs
The anti-platelet effect of passion flower may decrease the ability of blood to clot after an injury. Aspirin can also delay clotting, so passion flower should not be taken orally at the same time as aspirin.
The sleep-producing effects of over-the-counter products containing diphenhydramine or doxylamine may be enhanced by taking passion flower at the same time. Diphenhydramine and doxylamine are contained in many non-prescription sleeping pills as well as in some cough and cold products; therefore, caution should be used when taking these medications with passion flower because excessive drowsiness may result.
Herbal Products
Theoretically, if passion flower is used with other herbs that affect blood clotting, bleeding may occur. Some of the most common herbal products that might inhibit blood clotting are:
- Danshen
- Devil's Claw
- Eleuthero
- Garlic
- Ginger (in high amounts)
- Ginkgo
- Horse Chestnut
- Panax Ginseng
- Papain
- Red Clover
- Saw Palmetto
Although it is commonly sold as combination preparations with one or more other sleep-producing herbals, passion flower may cause excessive sedation if it is taken with other potentially sedating herbs such as:
- Catnip
- Hops
- Kava
- St. John's Wort
- Valerian
Foods
No interactions between passion flower and foods have been reported, but drinking alcohol at the same time as using passion flower by mouth may result in increased drowsiness.
Some interactions between herbal products and medications can be more severe than others. The best way for you to avoid harmful interactions is to tell your doctor and/or pharmacist what medications you are currently taking, including any over-the-counter products, vitamins, and herbals. For specific information on how passion flower interacts with drugs, other herbals, and foods and the severity of those interactions, please use our Drug Interactions Checker to check for possible interactions.
Should I take it?
Over 500 different species of passion flower are known in the world. All of them grow as perennial vines that thrive in tropical climates. Some species may survive in cooler areas such as southern California; and some are grown as decorative houseplants. The wood-like stems of passion flower are supported by tendrils similar to those found on grape vines. Like grape vines, passion flower vines may be planted along vineyard-like fences or netting for commercial production—especially in some African and South American countries. The vines bear distinctive flowers with five white petals and five magenta, purple, or blue petal-like sepals all surrounding a feathery circle of filaments. The Spaniards exploring South America in the 1500’s saw these flowers as representing Christ’s Crown of Thorns; hence, the Spanish name “Corona de Cristo”.
Flowers are followed by fruits that range according to species from pea-sized to the general size and shape of eggs. When ripe, the fruits may be yellow, orange, or dark purple, again depending on the species. Not all passion fruits are suitable for humans to eat, but some species of the heavily-seeded fruits are used for juice, often in combination with other tropical fruit juices, and these edible passion fruits may be eaten raw or cooked into jam. Recently, fruits from some species of passion flowers have been found to contain a high amount of lycopene, the pigment that gives tomatoes their red color. Lycopene may help to prevent or delay some cancers and heart disease. Other parts of the plant may have medical uses, as well. For example, the fruit rind may contain chemicals that widen blood vessels and lower blood pressure; the seeds may have antifungal effects.
For most medical use, however, the leaves and flowers of the passion vines are collected and dried. Passion flower is approved as a treatment for nervousness and restlessness by Commission E of the German Federal Institute for Drugs and Medical Devices, the German governmental agency that evaluates the safety and effectiveness of herbal products. The United States does not have a comparable agency to evaluate herbal products. However, about 25 years ago the U.S. Food and Drug Administration (FDA), required manufacturers to remove passion flower from non-prescription insomnia treatments that are sold in this country. The FDA felt that not enough evidence proving the safety or effectiveness of passion flower was available.
Dosage and Administration
Passion flower supplement are available in several different oral dosage forms, including liquid extracts and powders that may be added to foods and beverages. Directions for use vary by product and condition. Individuals who decide to use a commercial preparation of passion flower should follow the recommendations on the package.
Passion flower tea may be made by adding about a teaspoonful of dried passion flowers and leaves to about 6 ounces of boiling water and letting it soak for 10 minutes. The solid particles should be strained out before drinking the tea. To relieve insomnia, one cup of passion flower tea may be consumed about one hour before bedtime. For anxiety, up to four cups of passion flower tea may be taken per day. This tea may also be allowed to cool and then applied topically to minor skin irritations such as mild rashes or sunburn.
Summary
Taken orally, passion flower may be effective for reducing anxiety, promoting sleep, and lessening depression. When applied to the skin, it may help to relieve minor conditions such as scrapes and sunburn.
Risks
Due to the risk of miscarriage, pregnant women should not take passion flower. It should also be avoided by small children and women who are breast feeding.
Side Effects
In the past, rare instances of cyanide poisoning, blood vessel inflammation, and rapid heartbeat have been attributed to the use of passion flower products. The particular passion flower species that were involved may no longer be used as medicine or the products may have been contaminated with other plant material, however. More common side effects associated with the use of passion flower include confusion, dizziness, and nausea.
Interactions
Passion flower may increase the effects of drugs and herbals that promote sleepiness. It may also enhance the blood-thinning effects of anticoagulant and antiplatelet agents.
Last Revised May 18, 2007
References
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Last Revised May 18, 2007
Note: The above information is not intended to replace the advice of your physician, pharmacist, or other healthcare professional. It is not meant to indicate that the use of the product is safe, appropriate, or effective for you.
In general, herbal products are not subject to review or approval by the U.S. Food and Drug Administration (FDA). They are not required to be standardized, meaning that the amounts of active ingredients or contaminants they contain may vary between brands or between different batches of the same brand. Not all of the risks, side effects, or interactions associated with the use of herbal products are known because few reliable studies of their use in humans have been done.
This information is provided for your education only. Please share this information with your healthcare provider and be sure that you talk to your doctor and pharmacist about all the prescription and non-prescription medicines you take before you begin to use any herbal product.
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