Passion flower

Passion flower/Drug Interactions:

  • AnalgesicsAnalgesics: Theoretically, passion flower have synergistic effects when taken concomitantly with analgesics, such as aspirin, ibuprofen (Motrin?, Advil?), or naproxen (Naprosyn?, Aleve?, Anaprox?). An ethanolic extract of Passiflora incarnata elevated the nociceptive (pain) threshold and reduced activity in rats (29). However, studies of several individual alkaloids failed to demonstrate analgesic effects in rats (17).
  • Antianxiety drugsAntianxiety drugs: Based on animal study, chrysin may have anxiolytic properties similar to midazolam but to a lesser magnitude at the 2mg/kg dose used in this study (20).
  • AntibioticsAntibiotics: Anti-bacterial activity has been observed in extracts of several species of Passiflora, but have not been reported in Passiflora incarnata (7; 8).
  • Anticoagulants and antiplateletsAnticoagulants and antiplatelets: Passion flower contains coumarin (19) and therefore may increase bleeding risk (theoretical). Literature review reveals no reported cases of clinically significant bleeding in humans. Examples of anticoagulants and antiplatelets are warfarin (Coumadin?), heparin, and clopidogrel (Plavix?).
  • Anticonvulsant agentsAnticonvulsant agents: Based on animal study, Pasipay could be useful for the treatment of seizures and may have an effect on the GABAergic and opioid systems (10). More studies are needed in order to investigate its exact mechanism.
  • Antidepressant agentsAntidepressant agents: Harmala alkaloids, which possess monoamine oxidase-inhibiting activity, are reportedly found in small amounts in some species of Passiflora (19). Passion flower may therefore theoretically potentiate the activity of antidepressant agents. In combination with other antidepressants, such as tranylcypromine (Parnate?), amitriptyline (Elavil?), and fluoxetine (Prozac?), sedation or hypotension could theoretically be precipitated. However, levels of these alkaloids may be too low to be clinically relevant (30).
  • AntifungalsAntifungals: Anti-fungal activity has been observed in extracts of several species of Passiflora, but has not been reported in P. incarnata (7; 8).
  • AntihistaminesAntihistamines: Passion flower has documented CNS depressive effects and thus may have additive interactions with antihistamines (19; 18; 17; 29; 16).
  • AntihypertensivesAntihypertensives: Orally administered methanol extract of Passiflora edulis was found to have hypotensive properties in an animal study (12). Theoretically, concomitant use of antihypertensive agents and passion flower may result in additive blood pressure-lowering effects.
  • Antineoplastic agentsAntineoplastic agents: A compound, 4-hydroxy-2-cyclopentanone, isolated from P. tetrandra, has been found to exert cytotoxic effects on P388 murine leukemia cells (IC50 < 1(g/ml), but this evidence is preliminary (7).
  • Antispasmodic agentsAntispasmodic agents: There is an unpublished report of anti-muscarinic activity, which, if confirmed, could provide a basis for reported use as a gastrointestinal anti-spasmodic.
  • AntitussivesAntitussives: Theoretically, concomitant use with antitussives may lead to additive effects. The methanol extract of the leaves of Passiflora incarnata (100 and 200mg/kg, by mouth) exhibited significant antitussive activity on sulfur dioxide-induced cough in mice (4).
  • BarbituratesBarbiturates: Prolongation of barbiturate-induced sleep time (hexobarbital, pentobarbital) in mice and rats given passion flower has been demonstrated and interpreted by authors as suggesting interference with barbiturate metabolism (19; 31; 29).
  • BenzodiazepinesBenzodiazepines: In theory, potentiation of the CNS depressant effects of alcohol or other sedative-hypnotic drugs may occur with concomitant use of passion flower, based on animal data demonstrating a central benzodiazepine ligand isolated from Passiflora coerulea (16; 17; 18).
  • CaffeineCaffeine: Small amount of alkaloids with monoamine oxidase inhibiting activity are found in some species of passion flower. Taken concomitantly with caffeine, hypertension may result. However, alkaloid levels may be too low to be clinically relevant (30).
  • CNS depressantsCNS depressants: In theory, potentiation of the CNS depressant effects of alcohol, narcotics, or other sedative-hypnotic drugs may occur with concomitant use of passion flower, based on animal data demonstrating a central benzodiazepine ligand isolated from Passiflora coerulea (16; 17; 18). Prolongation of barbiturate-induced sleep time (hexobarbital, pentobarbital) in mice and rats given passion flower has been demonstrated and interpreted by authors as suggesting interference with barbiturate metabolism (19; 29).
  • Cytochrome P450 metabolized agentsCytochrome P450 metabolized agents: Theoretically, passion flower may interact with cytochrome P450 metabolized agents (32).
  • Disulfiram (Antabuse?)Disulfiram (Antabuse?): Many tinctures contain high levels of alcohol and may cause nausea or vomiting when taken with disulfiram (Antabuse?).
  • FlumazenilFlumazenil: According to one animal study, flumazenil and naloxone could suppress anticonvulsant effects of Passiflora (10).
  • Metronidazole (Flagyl?)Metronidazole (Flagyl?): Many tinctures contain high levels of alcohol and may cause nausea or vomiting when taken with metronidazole (Flagyl?).
  • NaloxoneNaloxone: According to one animal study, flumazenil and naloxone could suppress the anticonvulsant effects of Passiflora (10).
  • Neurologic agentsNeurologic agents: Passion flower may theoretically have synergistic effects when taken with sedatives (e.g., benzodiazepines or kava), CNS depressants (e.g., alcohol) (16; 17; 18), or anti-anxiety agents (20).
  • SedativesSedatives: In theory, potentiation of the CNS depressant effects of alcohol or other sedative-hypnotic drugs may occur with concomitant use of passion flower, based on animal data demonstrating a central benzodiazepine ligand isolated from Passiflora coerulea (16; 17; 18). Prolongation of barbiturate-induced sleep time (hexobarbital, pentobarbital) in mice and rats given passion flower has been demonstrated and interpreted by authors as suggesting interference with barbiturate metabolism (19; 29).

    • Passion flower/Herb/Supplement Interactions:

  • AnalgesicsAnalgesics: An ethanolic extract of Passiflora incarnata elevated the nociceptive (pain) threshold and reduced activity in rats (29). However, studies of several individual alkaloids failed to demonstrate analgesic effects in rats (17).
  • AntibacterialsAntibacterials: Anti-bacterial activity has been observed in extracts of several species of Passiflora, but have not been reported in Passiflora incarnata (7; 8).
  • Anticoagulants and antiplateletsAnticoagulants and antiplatelets: Theoretically, passion flower may have synergistic effects when taken with anticoagulants or antiplatelets, such as saw palmetto, garlic, or ginkgo. Passion flower contains coumarin (19), and therefore, may increase bleeding risk (theoretical); however, literature review reveals a lack of reported cases of clinically significant bleeding in humans.
  • AnticonvulsantsAnticonvulsants: Based on animal study, Pasipay could be useful for the treatment of seizures and may have an effect on the GABAergic and opioid systems (10). More studies are needed in order to investigate its exact mechanism.
  • Antidepressant agents, monoamine oxidase inhibitors (MAOIs)Antidepressant agents, monoamine oxidase inhibitors (MAOIs): Harmala alkaloids, which possess monoamine oxidase inhibiting activity, are reportedly found in small amounts in some species of Passiflora (19). Passion flower could therefore theoretically potentiate the activity of MAOI agents, such as kava. However, levels of these alkaloids may be too low to be clinically relevant.
  • Antidepressants, selective serotonin reuptake inhibitors (SSRIs)Antidepressants, selective serotonin reuptake inhibitors (SSRIs): Harmala alkaloids, which possess monoamine oxidase inhibiting activity, are reportedly found in small amounts in some species of Passiflora (19). Passion flower may therefore theoretically potentiate the activity of antidepressant agents. In combination with other antidepressants, sedation or hypotension could theoretically be precipitated. However, levels of these alkaloids may be too low to be clinically relevant (30).
  • AntifungalsAntifungals: Anti-fungal activity has been observed in extracts of several species of Passiflora, but have not been reported in Passiflora incarnata (7; 8).
  • AntihistaminesAntihistamines: Passion flower has documented CNS depressive effects in animal and lab studies and thus may have additive interactions with antihistamines (19; 18; 17; 29; 16).
  • AntineoplasticsAntineoplastics: A compound, 4-hydroxy-2-cyclopentanone, isolated from Passiflora tetrandra, has been found to exert cytotoxic effects on P388 murine leukemia cells (IC50 < 1mcg/mL), but this evidence is preliminary (7).
  • AntispasmodicsAntispasmodics: There is an unpublished report of anti-muscarinic activity, which, if confirmed, could provide a basis for reported use as a gastrointestinal anti-spasmodic.
  • AntitussivesAntitussives: Theoretically, concomitant use with antitussives may lead to additive effects. The methanol extract of the leaves of Passiflora incarnata (100 and 200mg/kg, by mouth) exhibited significant antitussive activity on sulfur dioxide-induced cough in mice (4).
  • AnxiolyticsAnxiolytics: Based on animal study, chrysin may have anxiolytic properties similar to midazolam but to a lesser magnitude at the 2mg/kg dose used in this study (20).
  • CaffeineCaffeine: Small amount of alkaloids with monoamine oxidase inhibiting activity are found in some species of passion flower. Taken concomitantly with caffeine, hypertension may result. However, alkaloid levels may be too low to be clinically relevant (30).
  • CoagulantsCoagulants: Passion flower contains coumarin (19) and therefore may theoretically decrease the effectiveness of coagulants. However, a literature review reveals no reported cases of clinically significant bleeding in humans.
  • Cytochrome P450 metabolized herbs and supplementsCytochrome P450 metabolized herbs and supplements: Theoretically, passion flower may interact with cytochrome P450 metabolized herbs and supplements (32).
  • Gastrointestinal herbs and supplementsGastrointestinal herbs and supplements: There is an unpublished report of anti-muscarinic activity, which, if confirmed, could provide a basis for reported use as a gastrointestinal anti-spasmodic.
  • HypotensivesHypotensives: Orally administered methanol extract of Passiflora edulis was found to have hypotensive properties in an animal study (12). Theoretically, concomitant use of antihypertensive agents and passion flower may result in additive blood pressure-lowering effects. (12)
  • KavaKava: Potentiation of the sedative effects of kava extracts by passion flower have been reported in mice (33).
  • LycopeneLycopene: Passion flower fruit contains lycopene and may have additive effects when taken with lycopene supplements, although clinical significance is unknown (34).
  • Neurologic herbs and supplementsNeurologic herbs and supplements: Passion flower may theoretically have synergistic effects when taken with sedatives (e.g., benzodiazepines or kava), CNS depressants (e.g., alcohol) (16; 17; 18), or anti-anxiety agents (20).
  • SedativesSedatives: In theory, potentiation of the CNS depressant effects of alcohol or other sedative-hypnotic agents, such as valerian, may occur with concomitant use of passion flower, based on animal data demonstrating a central benzodiazepine ligand isolated from Passiflora coerulea (16; 17; 18). Prolongation of barbiturate-induced sleep time (hexobarbital, pentobarbital) in mice and rats given passion flower has been demonstrated and interpreted by authors as suggesting interference with barbiturate metabolism (19; 29).

    • Passion flower/Food Interactions:

  • Lycopene-containing foodsLycopene-containing foods: Passion flower fruit contains lycopene and may have additive effects when taken with other lycopene-containing food, such as tomatoes, watermelon, pink grapefruit, pink guava, papaya, dried apricots, and pureed rosehips; however, clinical significance is unknown (34).
  • Tyramine or tryptophan-containing foodsTyramine or tryptophan-containing foods: Harmala alkaloids, which possess monoamine oxidase-inhibiting activity, are reportedly found in small amounts in some species of Passiflora (30). Passion flower could therefore theoretically interact with tyramine or tryptophan-containing foods, including red wine, cheeses, or aged foods, causing reactions including hypertensive urgency. However, alkaloid levels may be too low to be clinically relevant.

    • Passion flower/Lab Interactions:

  • International Normalized Ratio (INR)International Normalized Ratio (INR): Passion flower contains coumarin (19) and may theoretically increase bleeding INR. However, a literature review reveals no studies of passion flower and coagulation factors in humans.