To the Editor:

We congratulate Drs. Morris and Einhorn on their excellent review(1). However, we feel clarification is necessary on two issues mentioned in their article.

1. Although etidronate was the first available oral bisphosphonate in the U.S.A. and Europe, and is sometimes used to treat osteoporosis, it was never approved by the F.D.A. for this reason; in fact the application was denied. It is approved for the treatment of symptomatic Paget's disease of bone and heterotopic ossification(2,3). The only F.D.A. approved bisphosphonates for the treatment and prevention of osteoporosis are Ibandronate, Risedronate and alendronate.

2. Bisphosphonates are not the only medications shown to reduce the risk of hip fracture in large randomized trials; both conjugated equine estrogen(4) and strontium ranelate(5) have also been shown to reduce this risk, though the latter results were published only recently and strontium ranelate is currently not available in the U.S.A.

Bibliography:

1. Morris CD, Einhorn TA. Bisphosphonates in Orthopaedic Surgery. J Bone Joint Surg Am. 2005 Jul;87(7):1609-18.

2. Didronel Package Insert available at: http://www.pgpharma.com/pi/US-Didronel.pdf

3. Physician’s Desk Reference 2005; 59th Edition. Thomson PDR, New Jersey: 2805-6.

4. Anderson GL, Limacher M, Assaf AR, Bassford T, Beresford SA, Black H, Bonds D, Brunner R, Brzyski R, Caan B, Chlebowski R, Curb D, Gass M, Hays J, Heiss G, Hendrix S, Howard BV, Hsia J, Hubbell A, Jackson R, Johnson KC, Judd H, Kotchen JM, Kuller L, LaCroix AZ, Lane D, Langer RD, Lasser N, Lewis CE, Manson J, Margolis K, Ockene J, O'Sullivan MJ, Phillips L, Prentice RL, Ritenbaugh C, Robbins J, Rossouw JE, Sarto G, Stefanick ML, Van Horn L, Wactawski-Wende J, Wallace R, Wassertheil-Smoller S; Women's Health Initiative Steering Committee. Effects of conjugated equine estrogen in postmenopausal women with hysterectomy: the Women's Health Initiative randomized controlled trial. JAMA. 2004 Apr 14;291(14):1701-12.

5. Reginster JY, Seeman E, De Vernejoul MC, Adami S, Compston J, Phenekos C, Devogelaer JP, Curiel MD, Sawicki A, Goemaere S, Sorensen OH, Felsenberg D, Meunier PJ. Strontium ranelate reduces the risk of nonvertebral fractures in postmenopausal women with osteoporosis: Treatment of Peripheral Osteoporosis (TROPOS) study.J Clin Endocrinol Metab. 2005 May;90(5):2816-22.