Controlled studies are not available; therefore, interactions are based on evidence of pharmacological activity and are theoretical.
Additive effects are theoretically possible at high doses. Use with caution and monitor drug dosage — possible beneficial interaction under medical supervision.
Additive CNS sedation is theoretically possible. Use with caution and monitor drug dosage — possible beneficial interaction under medical supervision.
Increased risk of bleeding is theoretically possible owing to the coumarin content of the herb — observe patients taking this combination.
Drowsiness is theoretically possible with excessive doses.
One human study found that Passiflora extract has a significantly lower incidence of impairment of job performance compared with oxazepam. One case reports a 34-year-old woman who developed severe nausea, vomiting, drowsiness and episodes of non-sustained ventricular tachycardia following administration of passionflower at therapeutic doses.
Passionflower has demonstrated the ability to increase uterine contractions in an isolated rat uterus model when compared to control tissue. It is not advisable to use passionflower in pregnancy.