Passionflower (Passiflora incarnata) was used traditionally in the Americas and later in Europe as a "calming" herb for anxiety, insomnia, seizures, and hysteria. It is still used today to treat anxiety and insomnia. Although scientists aren't sure, it is believed that passionflower works by increasing levels of a chemical called gamma-aminobutyric acid (GABA) in the brain. GABA lowers the activity of some brain cells, making you more relaxed.
Passionflower tends to have effects that aren't as strong as valerian (Valeriana officinalis) or kava (Piper methysticum), two other herbs used to treat anxiety. Passionflower is often combined with valerian, lemon balm (Melissa officinalis), or other calming herbs. Few scientific studies have tested passionflower as a treatment for anxiety or insomnia, however. And because it is often combined with other calming herbs, it is difficult to tell what the effects of passionflower alone might be.
One study of 36 people with generalized anxiety disorder found that passionflower was as effective as the drug oxazepam (Serax) for treating symptoms. However, the study lacked a placebo group, so it is not considered to be definitive. In another study of 91 people with anxiety symptoms, researchers found that an herbal European product containing passionflower and other herbal sedatives significantly reduced symptoms compared to placebo. A more recent study found that patients who were given passionflower before surgery had less anxiety, but recovered from anesthesia just as quickly, than those given placebo.
Native to southeastern parts of the Americas, passionflower is now grown throughout Europe. It is a perennial climbing vine with herbaceous shoots and a sturdy woody stem that grows to a length of nearly 10 meters (about 32 feet). Each flower has 5 white petals and 5 sepals that vary in color from magenta to blue. According to folklore, passionflower got its name because its corona resembles the crown of thorns worn by Jesus during the crucifixion. The passionflower's ripe fruit is an egg-shaped berry that may be yellow or purple. Some kinds of passionfruit are edible.
The above-ground parts (flowers, leaves, and stems) of the passionflower are used for medicinal purposes.
Available forms include the following:
- Liquid extracts
How to Take It
No studies have examined the effects of passionflower in children, so do not give passionflower to a child without a doctor's supervision. Adjust the recommended adult dose to account for the child's weight. Most herbal dosages for adults are calculated on the basis of a 150 lb (70 kg) adult. So if a child weighs 50 lb (20 - 25 kg), the appropriate dose of passionflower for this child would be 1/3 of the adult dosage.
The following are recommended adult doses for passionflower:
- Tea: Steep 0.5 - 2 g (about 1 tsp.) of dried herb in 1 cup boiling water for 10 minutes; strain and cool. For anxiety, drink 3 to 4 cups per day. For insomnia, drink one cup an hour before going to bed.
- Fluid extract (1:1 in 25% alcohol): 10 - 30 drops, three times a day
- Tincture (1:5 in 45% alcohol): 10 - 60 drops, three times a day
The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, can trigger side effects and can interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a health care provider.
Do not take passionflower if you are pregnant or breastfeeding.
For others, passionflower is generally considered to be safe and nontoxic in recommended doses.
Passionflower may interact with the following medications:
Sedatives (drugs that cause sleepiness) -- Because of its calming effect, passionflower may make the effects of sedative medications stronger. These can include:
- Anticonvulsants such as phenytoin (Dilantin)
- Benzodiazepines such as alprazolam (Xanax) and diazepam (Valium)
- Drugs for insomnia, such as zolpidem (Ambien), zaleplon (Sonata), eszopiclone (Lunesta), ramelteon (Rozerem)
- Tricyclic antidepressants, such as amitriptyline (Elavil), amoxapine, doxepin (Sinequan), and nortriptyline (Pamelor)
Antiplatelets and anticoagulants (blood thinners) -- Passionflower may increase the amount of time blood needs to clot, so it could make the effects of blood-thinning medications stronger and increase your risk of bleeding. Blood-thinning drugs include:
- Clopidogrel (Plavix)
- Warfarin (Coumadin)
Monoamine oxidase inhibitors (MAO inhibitors or MAOIs) -- MAO inhibitors are an older class of antidepressants that are not often prescribed now. Theoretically, passionflower might increase the effects of MAO inhibitors, as well as their side effects, which can be dangerous. These drugs include:
- Isocarboxazid (Marplan)
- Phenelzine (Nardil)
- Tranylcypromine (Parnate)