Herb-Drug Interactions: Passiflora
Passiflora incarnata L. (Passifloraceae)
Synonym(s) and related species
Apricot vine, Maypop, Passion flower, Passion vine.
Note that Passiflora edulis Sims is the source of the edible passion fruit.
Pharmacopoeias
Passion Flower (British Ph 2009, European Ph 2008); Passion Flower Dry Extract (British Ph 2009, European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4).
Constituents
The major constituents of passiflora leaf and flower are C-glycosides of flavonoids based on apigenin and luteolin, to which it may be standardised. Other flavonoids present include chrysin (5,7-hydroxyflavone), quercetin and kaempferol. The indole alkaloids of the P-carboline type (e.g. harman, harmol and others) are minor constituents or may not even be detectable. Other minor constituents include a cyanogenic glycoside gynocardin, gamma-benzopyrones maltol and ethylmaltol, a polyacetylene passicol and an essential oil.
Use and indications
Passiflora is used as a sedative, hypnotic and anxiolytic and has been reported to have antiepileptic and anti-inflammatory effects. Some clinical studies in patients appear to support the anxiolytic and sedative effects of passiflora, and animal data suggest that some of the flavonoid constituents, chrysin and apigenin, may be responsible for these effects.
Pharmacokinetics
No relevant pharmacokinetic data found. For information on the pharmacokinetics of individual flavonoids present in passiflora, see under flavonoids.
Interactions overview
Passiflora is used for its sedative effects; additive sedation is therefore a theoretical possibility with other drugs with sedative properties, whereas the effects of stimulant drugs may be reduced. For information on the interactions of individual flavonoids present in passiflora, see under flavonoids.
Passiflora + Amfetamines
The interaction between passiflora and amfetamines is based on experimental evidence only.
Evidence, mechanism, importance and management
A study in rats reported that a passiflora extract 250mg/kg reduced the hyperactivity induced by subcutaneous amfetamine by 39%, when compared with a control group who received amfetamine alone. This effect was reduced by 83% when a Piper methysticum (kava) extract 100 mg/kg was also given.
Although this was a high-dose study in animals, these results appear to be in line with the known sedative effects of passiflora. Bear in mind the possibility of antagonistic effects when passiflora is given with stimulants.
Passiflora + Anxiolytics and Hypnotics
The interaction between passiflora and phenobarbital is based on experimental evidence only.
Evidence, mechanism, importance and management
A study in rats found an additive sedative effect when a passiflora extract 250mg/kg was given with phenobarbital. This was reported as a 53% increase in sleep duration. This effect was greater (92%) when Piper methysticum (kava) extract 100 mg/kg was also given.Although this was a high-dose study in animals, these results appear to be in line with the known sedative effects of passiflora. Bear in mind the possibility of additive sedative effects when passiflora is taken with other known sedative drugs.
Passiflora + Food
No interactions found.
Passiflora + Herbal medicines; Kava
The effects of passiflora extract and Piper methysticum (kava) extract were synergistic in one animal study, see Passiflora + Amfetamines, above, and Passiflora + Anxiolytics and Hypnotics, above.
