From Mr H.A. Tyrrell, MRPharmS
SIR,—My wife recently received an unsolicited mailing announcing the availability of a new health food calcium supplement, Osteopro, containing ipriflavone. It stated that this had been shown to promote healthy bone formation, inhibiting the activity of bone-degrading cells, osteoclasts.
Curiosity prompted me to investigate further and it appears that ipriflavone is a synthetic isoflavone which is also reported to occur naturally in bee propolis, although this is disputed. It is available as a prescription medicine for the treatment of osteoporosis in Italy under the trade names Iprosten 200 and Osteofix 200 with prescribing information which includes the following:
Contraindications Active gastric and duodenal ulcers, lymphocytopenia, pregnancy.
Warnings Caution in patients with severe liver, renal or haematological disorders. Monitor liver and hepatic function and blood cell counts on long term treatment. Not suitable for infants/children. Caution in lactation as in animal studies it passes into milk.
Interactions Augments coumarin anticoagulants, monitor clotting times and adjust dose.
A Medline search also revealed that ipriflavone inhibits cytochrome P450 enzymes and has resulted in increased patient blood theophylline levels. None of this information is included in the Osteopro leaflet.
Apart from the question of the suitability of this type of product for general distribution, there is clearly a need for much more information to accompany such products for the benefit of both the public and their professional advisers.
H. Tyrrell
Horsham, West Sussex