Passionflower

Purported Benefits, Side Effects & More
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This information describes the common uses of Passionflower, how it works, and its possible side effects.
Tell your healthcare providers about any dietary supplements you’re taking, such as herbs, vitamins, minerals, and natural or home remedies. This will help them manage your care and keep you safe.

What is it?

Passionflower may reduce anxiety, but its long-term safety and effectiveness are not known.

Passiflora incarnata is a perennial wildflower that is commonly found in the southern United States. Passionflower extract is contained in many dietary supplement products marketed as sleep aids or anxiety relievers. A handful of studies in humans support these claims, although it is still unknown whether passionflower extracts are safe and effective in the long-term. Scientists are not sure how this herb works, but have speculated that compounds in passionflower may interact with receptors in the brain that would mediate a relaxation response. Studies done in mice suggest that passionflower extracts have mild anti-inflammatory and anti-seizure activity.

Because animal studies show disrupted sexual behavior in male offspring, passionflower should be avoided during pregnancy. It may also interact with certain medications as well as have added effects with St. John’s wort and/or valerian.

What are the potential uses and benefits?

  • To relieve anxiety
    Small studies suggest that passionflower may be as effective as oxazepam, a common drug used for treating general anxiety, and help reduce anxiety in presurgical patients.
  • As a sleep aid, for insomnia
    Passionflower may reduce anxiety (see above), which may help induce sleep. A small study showed benefits of passionflower in sleep quality in healthy adults.
  • To treat nerve pain
    Evidence is lacking to support this claim.
  • To treat attention-deficit hyperactivity disorder (ADHD)
    A small study in children suggests that passionflower may reduce ADHD symptoms similar to a prescription drug but with fewer side effects.

What are the side effects?

  • Dizziness
  • Sedation
  • Lack of muscle coordination
  • Allergic reaction
  • Impaired cognitive function

Large doses may result in central nervous system depression and slowed or irregular heart rhythms.

Case reports

  • A 34-year-old woman required hospital admission with symptoms of nausea, vomiting, decreased heart rate, and heart rhythm abnormalities after using a passionflower supplement.
  • A patient who self-medicated with valerian and passionflower while on anti-anxiety therapy experienced hand tremors, dizziness, throbbing and muscular fatigue suspected to be caused by using these products together.
  • Passionflower was among the 10 most frequently reported plants to cause neurotoxicity and gastrointestinal symptoms (29).

What else do I need to know?

Do Not Take if:

  • You are taking pentobarbital: Passionflower may have additive effects. Clinical relevance is not known.
  • You are taking benzodiazepines such as Ativan® or Valium®: Passionflower may increase the sedative effects of these medications. Clinical relevance is not known.
  • You are taking drugs that prolong the QT interval (eg, azithromycin, dasatinib, fingolimod): The QT interval shows the electrical activity in the heart’s lower chambers, the ventricles. Because lab analyses suggest passionflower may also prolong QT interval with large doses, it is not known whether passionflower may have added cardiac effects with these medications.
  • You are pregnant: Passionflower should be avoided because it may cause uterine contraction and behavioral dysfunction in offspring.