How It Works
Bottom Line: Passionflower may reduce anxiety, but its long-term safety and effectiveness are not known.
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 activity.
Purported Uses
To relieve anxiety
One small clinical trial suggested that passionflower may be as effective as oxazepam, a common drug used for treating general anxiety. In addition, another clinical trial showed that passionflower reduced anxiety in presurgical patients. However, the safety and effectiveness of its long-term use are not known.
As a sleep aid, for insomnia
Passionflower may reduce anxiety (see above), which may help induce sleep, but there is no proof from clinical trials that passionflower can treat insomnia.
To treat neuralgia (nerve pain)
Passionflower may help reduce anxiety (see above), and could thereby reduce the perception of pain. However, other than this theoretical association, no scientific evidence supports the use of passionflower for nerve pain.
Research Evidence
Generalized anxiety disorder
A small clinical trial compared a passionflower extract (Passipay™) to a commonly used benzodiazepine (oxazepam) in treating generalized anxiety disorder. Because Passipay™ is a liquid and oxazepam a capsule, the study was designed so that the patients did not know which medication they were receiving: 18 patients received 45 drops/day of passionflower extract liquid plus a placebo capsule, while the other 18 took 30 mg/day oxazepam plus 45 drops of a placebo liquid. After four weeks, the researchers concluded that the passionflower extract was as effective as oxazepam in relieving anxiety. Patients in both groups reported similar side effects, including sedation, dizziness, and confusion, but more patients on oxazepam reported impaired job performance. These results are promising, but larger clinical trials that use passionflower for a longer period of time are needed. It should be noted that the results of this study might not apply to other brands of passionflower extract.
The use of preoperative oral passionflower for anxiety in 60 patients was examined in this study. Patients were either given passionflower (500 mg, Passipy™ IranDarouk) or placebo 90 minutes before their surgery and anxiety was measured at different time points before surgery. In patients that received passionflower, anxiety was reduced compared to the placebo group. However, larger studies are required.
Do Not Take If
You are taking pentobarbital (Passionflower may have additive effects).
You are taking benzodiazepines such as Ativan® or Valium® (Passionflower may increase the sedative effects of these medications).
You are taking warfarin or other blood thinners (Passionflower may increase the risk of bleeding).
You regularly consume alcohol (Passionflower can increase the sedative effects of alcohol).
Side Effects
Dizziness
Sedation
Ataxia (lack of coordinated muscle activity)
Allergic reaction
Impaired cognitive function
Case report: One patient experienced nausea, vomiting, decreased heart rate, and several abnormalities in heart rhythm after using a passionflower supplement. The patient recovered once the supplement was discontinued.
Special Point
Passionflower extracts that are available over-the-counter are not always standardized with respect to content and activity, and therefore dosages may vary.
Scientific Name
Passiflora incarnata
Common Name
Maypop, apricot vine, passion vine, purple passion flower, fleur de la passion, passiflore, corona de cristo, maracuja
Brand Name
Sedacalm®, Passipay™, Passipy™ IranDarouk
Clinical Summary
Derived from the aerial parts of the plant, passionflower is used by patients to treat insomnia, anxiety, epilepsy, neuralgia, and withdrawal syndromes from opiates or benzodiazepines. The active component of passionflower is unknown. The alkaloid components (e.g., harman, harmaline) are thought to produce monoamine oxidase inhibition, while other constituents, like maltol and gamma-pyrone derivatives, cause activation of GABA receptors (1). Theoretically, passionflower may potentiate the sedative effect of centrally acting substances (e.g., benzodiazepines, barbiturates, alcohol) (2). A small pilot study evaluated passionflower for generalized anxiety and showed comparable efficacy to oxazepam (3), but a systematic review concluded that randomized controlled studies are needed to confirm such effects (4). In patients undergoing surgery, preoperative passionflower use reduced anxiety (5). Not all passionflower extracts are standardized because of which dosages and activities may vary. Reported adverse events include sedation, dizziness, impaired cognitive function, and one case report of nausea, vomiting, and ECG changes. Adverse events subsided following discontinuation of passionflower use (3) (6).
Purported uses
Benzodiazepine withdrawal
Drug withdrawal symptoms
Epilepsy
Insomnia
Neuralgia
Constituents
Alkaloids: Harman, harmaline, harmalol, harmol, harmine
Flavonoids: Vitexin, isovitexin, apigenin, luteolin glycosides (orientin, homoorientin, lucenin), kaempferol, quercetin, rutin
Other: Carbohydrates, benzopyrones, fatty acids, gamma-pyrone derivatives (maltol, ethylmaltol), passicol
(7)(8)(9)
Mechanism of Action
The exact mechanism of action is unknown. Activation of GABA receptors by maltol and gamma-pyrone derivatives may account for passionflower's anxiolytic and sedative properties
(10). It is suggested that the harman alkaloids have monoamine oxidase inhibitor activity
(1). Passionflower exhibits mild anti-inflammatory activity
(11). An ethanolic extract of passionflower reduced carrageenan-induced edema, leukocyte migration, and granuloma formation in mice, although the effect was less than that seen with aspirin
(12).
Pharmacokinetics
No formal pharmacokinetic studies have been conducted.
Warnings
Because it is not regulated by the F.D.A., this product may be contaminated with other botanicals and/or the concentration listed on the label may be inaccurate.
Adverse Reactions
Reported: Dizziness, sedation, ataxia, allergic reaction, and impaired cognitive function (3).
Case report: Nausea, vomiting, bradycardia, and ECG changes including non-sustained ventricular tachycardia, QTc prolongation, and nonspecific ST-T wave changes. Patient recovered following discontinuation of supplement (6).
Herb-Drug Interactions
Pentobarbital: Passionflower may potentiate the effects of pentobarbital
(2).
Benzodiazepines: Theoretically, passionflower may increase the sedative effects of
benzodiazepines.
Anticoagulant: Passionflower may have additive anticoagulant effect.
Alcohol: Theoretically, passionflower may increase the sedative effects of alcohol
(13).
Literature Summary and Critique
Akhondzadeh S, et al. Passionflower in the treatment of generalized anxiety: a pilot double-blind randomized controlled trial with oxazepam. J Clin Pharm Ther 2001;26:363-7.
A prospective, randomized, placebo-controlled evaluation of 45 drops/day passionflower extract liquid (Passipay™) plus placebo capsule (n=18) compared to 30 mg/day oxazepam capsule plus placebo liquid (n=18) on patients with generalized anxiety disorder and a Hamilton Anxiety Rating greater than 14. Primary outcome was change in Hamilton Anxiety Rating scale (HAM-A) from baseline as evaluated by a psychiatrist. The author states that passionflower was as effective as oxazepam after 4 weeks of therapy, but average scores at day 28 are not reported. Adverse effects were similar between groups, including sedation, dizziness, and confusion, although more patients on oxazepam reported impaired job performance. Passionflower appears to be as effective as oxazepam, but larger studies are necessary.
Akhondzadem S, et al. Passionflower in the treatment of opiates withdrawal: a double-blind randomized controlled trial. J Clin Pharm Ther 2001;26:369-73.
A prospective, randomized, double-blind evaluation of 0.3-0.8 mg/day clonidine with or without 60 drops/day passionflower extract for 14 days in male opiate addicts who agreed to detoxification. Primary outcome measure was the Short Opiate Withdrawal Scale, consisting of both physical and mental scores. Following randomization, a total of 30 evaluable patients remained in each arm. No significant difference in efficacy was documented between groups. The author suggests that passionflower may be of use in opiate withdrawal, but additional studies are required.
Movafegh A, et al. Preoperative oral Passiflora incarnata reduces anxiety in ambulatory surgery patients: a double-blind, placebo-controlled study. Anesth Analg. Jun 2008;106(6):1728-1732.
To determine if preoperative oral passionflower could alter anxiety, 60 ambulatory surgery patients received passionflower (500 mg, Passipy™ IranDarouk) or placebo 90 minutes prior to surgery. Both anxiety and sedation were assessed using the numerical rating scale (NRS) at different time points before the surgery. Psychomotor evaluations were also performed. Whereas the NRS anxiety scores were significantly reduced in the intervention group as compared to the placebo group, no other differences were detected, suggested that passionflower effectively reduces pre-surgical anxiety without altering psychomotor function. Further studies are necessary to determine if passionflower can reduce anxiety in patients undergoing more extensive surgery.
References
1. Dhawan K, Kumar S, Sharma A.
Anti-anxiety studies on extracts of Passiflora incarnata Linneaus. J Ethnopharmacol. Dec 2001;78(2-3):165-170.
2. Speroni E, Billi R, Mercati V, et al. Sedative effects of crude extract of passiflora incarnata after oral administration. Phytotherapy Res 1996;10:S92-S94.
3. Akhondzadeh S, Naghavi HR, Vazirian M, et al.
Passionflower in the treatment of generalized anxiety: a pilot double-blind randomized controlled trial with oxazepam. J Clin Pharm Ther. Oct 2001;26(5):363-367.
4. Miyasaka LS, Atallah AN, Soares BG.
Passiflora for anxiety disorder.
Cochrane Database Syst Rev. 2007(1):CD004518.
5. Movafegh A, Alizadeh R, Hajimohamadi F, et al.
Preoperative oral Passiflora incarnata reduces anxiety in ambulatory surgery patients: a double-blind, placebo-controlled study.
Anesth Analg. Jun 2008;106(6):1728-1732.
6. Fisher AA, Purcell P, Le Couteur DG.
Toxicity of Passiflora incarnata L. J Toxicol Clin Toxicol. 2000;38(1):63-66.
7. Dhawan K, Kumar S, Sharma A.
Anxiolytic activity of aerial and underground parts of Passiflora incarnata. Fitoterapia. Dec 2001;72(8):922-926.
8. Grice ID, Ferreira LA, Griffiths LR. Identification and simultaneous analysis of harmane, harmine, harmol, isovitexin, and vitexin in passiflora incarnata extracts with a novel hplc method.
J Liq Chrom Rel Technol 2001;24(16):2513-2523.
9. Newall CA, Anderson LA, Phillipson JD. Herbal Medicines:
A Guide for Health-Care Professionals. 1st ed. London: Pharmaceutical Press; 1996.
10. Grundmann O, Wang J, McGregor GP, et al.
Anxiolytic Activity of a Phytochemically Characterized Passiflora incarnata Extract is Mediated via the GABAergic System. Planta Med. 2008 Dec;74(15):1769-73.
11. Soulimani R, Younos C, Jarmouni S, et al.
Behavioural effects of Passiflora incarnata L. and its indole alkaloid and flavonoid derivatives and maltol in the mouse. J Ethnopharmacol. Jun 1997;57(1):11-20.
12. Borrelli F, Pinto L, Izzo AA, et al. Anti-inflammatory activity of passiflora incarnata l. in rats.
Phytotherapy Res. 1996;10:S104-S106.
13. Brinker F.
Herb Contraindications and Drug Interactions. 3rd ed. Sandy (OR): Eclectic Medical Publications; 2001.
