Bottom Line: Passionflower may reduce anxiety, but its long-term safety and effectiveness are not known.
Passionflower extract is contained in products such as Sedacalm® and Passipay™, which are 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. It is possible that passionflower works in a similar way to benzodiazepines (by activating GABA receptors) or to MAOIs (by inhibiting monoamine oxidase and allowing excitatory neurotransmitters to remain active in the brain longer). In addition, studies in mice have suggested that passionflower extracts have mild anti-inflammatory activity.
To relieve anxiety One small clinical trial suggested that passionflower may be as effective as oxazepam for treating generalized anxiety disorder, but the safety and effectiveness of its long-term use are not known.
To reduce withdrawal symptoms when stopping medications such as benzodiazepines or opiates (heroin, morphine, percocet) One clinical trial showed that passionflower eased the mental, but not physical symptoms of opiate withdrawal when combined with clonidine, but further research is needed in this area.
To treat epilepsy No scientific evidence supports this use. 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 thereby reduce the perception of pain. However, other than this theoretical association, no scientific evidence supports the use of passionflower for neuralgia.
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.
Opiate withdrawal Sixty men who were undergoing withdrawal from an opiate drug (such as heroin, morphine, or percocet) were randomly assigned to one of two groups: (1) clonidine alone or (2) clonidine plus 60 drops/day passionflower extract. After two weeks, these two groups had similar physical symptoms of withdrawal, but the group taking passionflower had fewer mental symptoms. More research is needed.
Case report: One patient experienced nausea, vomiting, slowed heart rate, and several abnormalities in heart rhythm after using a passionflower supplement. The patient recovered once the supplement was discontinued.
Derived from the aerial parts of the plant. Patients use this herb 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 the maltol and gamma-pyrone derivatives cause activation of GABA receptors (4). Reported adverse events include sedation, dizziness, impaired cognitive function, and one case report of nausea, vomiting, and ECG changes. All adverse events subside following discontinuation of passionflower (7)(8). Theoretically, passionflower may potentiate the sedative effect of centrally acting substances (e.g. benzodiazepines, barbiturates, alcohol) (10). A small pilot study evaluated passionflower for generalized anxiety and showed comparable efficacy to oxazepam (8), but a systematic review concluded that randomized controlled studies are needed to confirm such effects (12). Passionflower may be of use in combination with clonidine for opiate detoxification, but additional research is required. No standardization exists for passionflower extract, therefore dosages and activities may vary.
The exact mechanism of action is unknown. Activation of GABA receptors by maltol and gamma-pyrone derivatives may mediate passionflower's anxiolytic and sedative properties. It is suggested that the harman alkaloids have monoamine oxidase inhibitor activity (4). Passionflower exhibits mild anti-inflammatory activity (6). 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 (5).
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.
Reported: Dizziness, sedation, ataxia, allergic reaction, and impaired cognitive function (8). 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 (7).
Pentobarbital: Passionflower may potentiate the effects of pentobarbital (10). 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. (9)
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.
