This section is from the book "A Practitioner's Handbook Of Materia Medica And Therapeutics", by Thos. S. Blair. Also available from Amazon: A Practitioner's handbook of Materia Medica and Therapeutics.
Passiflora Incarnata, Passion Flower. The physiologic action of this remedy has not been well studied, but animals eating of it in large quantities suffer from spasm and paralysis.
In moderate doses in man it is classed as a narcotic and antispasmodic. It has been exploited in proprietary circles, and is overstated in the literature issued. I have made large use of the agent, and find the fluidextracts to vary. The @ is excellent, but too weak for a feeble drug like passiflora.
The ec. tr. is made of the root and stem stalks, and is claimed to be more potent than fluidextracts, but I believe some of them equal it in strength. As an antispasmodic it is of more value than as a narcotic. A few cases of tetanus are recorded in which large doses were effective. It seems to cure tetanus in horses very promptly, but is not nearly so successful in man, and must be given in tablespoonful doses of the fluidextract. The spasms of meningitis yield to it more readily, while in epilepsy it seems to have an effect in reducing the frequency of the paroxysms, but large doses must be given. In the convulsions of children it is quite a reliable drug in doses of 10 to 15 I. of the fluidextract. As a narcotic it produces normal sleep, and the patient can be readily aroused. No disagreeable symptoms follow its use, but it must be steadily borne in mind that passiflora does not relieve pain and is utterly worthless as a hypnotic in insomnia with flushed face and cerebral congestion. Bromides are demanded in this condition. On the other hand, in asthenic insomnia due to exhaustion and depressing fevers, in insomnia due to functional nerve disturbances, neuroses without pain, and in insomnia of infants and the aged, it is a useful and entirely harmless drug. It acts nicely with children. Small doses are of no value.