Pharmacological treatments for osteoporosis must be administered on a long-term basis in order to continuously reduce the risk of low- trauma fractures. As such, pharmacists should endeavour to encourage compliance with medications prescribed for osteoporosis and to ensure that adequate doses of calcium and vitamin D are prescribed. In managing osteoporosis treatments, patient counselling is a key consideration as dosing regimens may be complex and patients elderly.

Royal College of Physicians Guidelines
The Royal College of Physicians' guidelines for the treatment and management of osteoporosis recommend the following lifestyle advice for people at risk of osteoporosis:

• Adequate nutrition, especially with calcium and vitamin D.
• Regular weight-bearing exercise
• Avoidance of tobacco use and alcohol use.

Following measurement of the BMD of an at-risk patient, the following advice is given:

• Patients with a normal T score (-1 or above) should be given the lifestyle advice listed above and reassured about their bone mass density.
• Patients with Osteopaenia (a T score of -1 to -2.49) should be given the lifestyle advice listed above and treatment if a previous fragility fall has occurred.
• Patients with Osteoporosis (a T score of less than -2.5) should be given the lifestyle advice listed above and treatment with a bisphosphonate or another appropriate osteoporosis medication in conjunction with a vitamin D and calcium supplement.

This document can be read in full at http://www.rcplondon.ac.uk/pubs/wp_osteo_update.htm

Calcium and Vitamin D
An adequate dietary level of calcium (800mg per day) has been shown to prevent bone loss and to decrease the risk of developing osteoporosis. High-risk patients should take higher doses of calcium - one gram or more per day; while this decreases the loss of bone mass, the incidence of fractures does not seem to be affected. As such, calcium intake should be considered as primary prevention of osteoporosis but only as an adjunct in secondary prevention or treatment.

Vitamin D in conjunction with parathyroid hormone (PTH) is responsible for the control of serum calcium levels. Once absorbed and metabolized, vitamin D promotes the absorption of dietary calcium and - with PTH - enhances bone resorption, producing an increased level availability of calcium for new bone formation.

In trials where calcium was used with vitamin D, the two agents combined to increase bone mass and decrease fracture rates in post-menopausal women and elderly men.

The advantages of using calcium and vitamin D in combination - in preparations such as Ideos, Calcichew D3Forte or Osteofos D3 - include that they are generally well tolerated by patients, that they can significantly reduce the risk of hip and vertebral fractures, and that they are inexpensive to provide.

For patients with established osteoporosis, however, calcium and vitamin D are not as effective as bisphosphonates, HRT or SERMs, although they do act as an effective adjunct to these treatments.

Calcitriol
An analogue of vitamin D, calcitriol has been shown to have an effect in reducing vertebral fractures, but not hip fractures, in post-menopausal women. It can be useful as a treatment for men or pre-menopausal women or for patients for whom HRT, bisphosphonates or SERMs are unacceptable. Side effects of calcitriol include the risk of hypercalcaemia, hyperuricaeia and nephrocalcinosis.

Calcitonin
Calcitonin is licensed for the treatment of post-menopausal osteoporosis in combination with calcium and vitamin D. A powerful inhibitor of osteoclast activity which results in increases in bone density, calcitonin can be administered intranasally or by subcutaneous injection. However, its use has been limited because of its adverse effects - nausea and vomiting, as well as facial flushing - which have affected compliance. In comparison to other drugs, calcitonin's efficacy in preventing fractures is less well established, although it may be used in the acute phase of osteoporosis for its analgesic effects on patients with vertebral fractures. It may also be used to retard bone loss at a time of immobilisation.

Bisphosphonates - Alendronate, Risedronate and Etidronate
All three bisphosphonates are licensed for the prevention and treatment of osteoporosis, including corticosteroid-induced osteoporosis. They act by inhibiting the dynamic resorption of bone by decreasing the number and activity of osteoclasts. Alendronate and risedronate have been shown to reduce hip and spine fractures while etidronate has only been shown to reduce spine fractures.

Alendronate and risedronate have a rapid onset of action, with the risk of fractures dropping within 12 to 18 months. There is uncertainty, however, as to the effects that long-term exposure of the younger skeleton to bisphosphonates may have due to the suppression of bone turnover and the possibility of 'frozen' bone. As such, most clinicians restrict usage of bisphosphonates in early postmenopausal women to those with the highest risk of fracture. Treatment with bisphosphonate is usually reviewed after five years.

Selective Oestrogen Receptor Modulators (SERMs) - Raloxifene
SERMs can be used for the prevention of osteoporosis in post-menopausal women and are recommended as an alternative treatment option for women for whom bisphosphonates are contraindicated. They act as an oestrogen agonist in the cardiovascular system and in the skeleton, decreasing bone resorption. SERMs also act as an oestrogen antagonist in endometrial and breast tissue. As such, they may actually decrease cancer risk, particularly breast cancer.

Raloxifene is generally well tolerated and, in contrast to combined HRT, does not appear to increase the risk of cardiovascular disease. Contraindications for raloxifene include the risk of DVTs - especially during the first four months of treatment - as well as a worsening of menopausal symptoms such as minor flushing and sweats.

Teriparatide
Teriparitide is administered by daily subcutaneous injection and is available in Ireland through the high tech medicines scheme (as Forsteo). It induces several growth factors and enhances collagen synthesis and has been shown to rapidly increase BMD in severe osteoporosis.

Teriparitide is recommended as a treatment option for women over 65 who have had an unsatisfactory response bisphosphonates and who have an extremely low BMD (T score of -4 or less) or who have a very low BMD (T score of -3 or less) in conjunction with multiple fractures and additional, age-independent risk factors.

The use of teriparitide is restricted to 18 months and, currently, only parenteral administration is possible.

Hormone Replacement Therapy (HRT)
HRT is known to cause an increase in BMD but it has not been proved to reduce fracture rates. Although prescribing of HRT has decreased greatly due to concerns about its long term risks - increased risk of breast cancer, CHD, DVT and stroke - it remains an option for women over fifty who are unable to tolerate bisphosphates and for whom menopausal symptoms are a significant problem. It should be noted, however, that HRT treatments need to be given for at least seven years to realise the maximum benefits and that, on discontinuation of HRT, the patient will revert back to the same risk that she initially had. Treatment with HRT should be re-evaluated at least annually.

Strontium Ranelate
Strontium is the first in a new class of drugs for osteoporosis called dual-acting bone agents (DABAs). It simultaneously increases bone formation and decreases bone resorption, mimicking the physiological coupling effect of bone resorption and formation in healthy bone. Studies have shown strontium to be effective in decreasing vertebral, non-vertebral and hip fractures. It is generally well tolerated and good compliance has been shown in patients. Unlike bisphosphonates, strontium promotes the development of healthy new bone rather than potentially leading to older bone in the long-term. Strontium ranelate is administered in sachets of tasteless powder for suspension in water. The dose for treatment of osteoporosis is two grams per day, taken at bedtime at least two hours after eating.

Related articles:
Osteoporosis - an introduction
Medicines and Falls
Preventing Falls in the Elderly
Useful Websites: Osteoporosis and Falls Prevention

This article was prepared by Julie Cronin and is based on the ICCPE live learning course Preventing Falls in the Elderly, given by Eileen Relihan.