Specific Medical Treatment * (List of available drugs below)
The aim of specific medication used in the treatment of established osteoporosis is to stop further bone loss, to replace or repair bone and to prevent further fractures. These drugs can be divided into two broad groups- those that inhibit bone resorption (chewing away of bone) and those that stimulate bone formation (building new bone).
Anti-resorptives serve mainly to slow bone breakdown and include calcium, vitamin D, oestrogen, SERM's, bisphosphonates and calcitonin. They act primarily to maintain bone mass.
Bone- formation stimulating drugs aim to increase bone mass and include fluoride, anabolic steroids, strontium salts, statins and para-thyroid hormone.
All patients with osteoporosis should ensure a calcium intake of at least 1000-1500mg per day- especially the elderly where a 25% reduction in the incidence of hip fractures has been reported following calcium supplementation.
Vitamin D and Vitamin D-metabolites
Low dose vitamin D (400-800IU/day) will ensure adequate calcium absorption in healthy, young individuals. In the elderly, housebound patient larger doses of vitamin D (50,000IU every two weeks) may have to be considered. Vitamin D has also been shown to improve muscle strength and co-ordination. When high doses of vitamin D are taken, blood and urine levels of calcium may rise and cause kidney stones. Careful monitoring by a physician is imperative.
Vitamin D metabolites (calcitriol, alfa- calcidiol) have been shown to decrease the rate of spine fractures.
Conventional Hormone Replacement Therapy
HRT is most effective in maintaining bone mass within the first 5-10 after the menopause and can prevent fractures by almost 50%. It is however not recommended as first line treatment (as opposed to the prevention) of osteoporosis.
Oestrogen derivatives, selective oestrogen receptor modulators (SERM's), phyto-oestrogens and testosterone
SERM's like raloxifene have oestrogen-like effects on bone and lipids and anti-oestrogen effects on the breast and uterus. It is not associated with menstrual bleeds and breast cancer. Hot flushes are the most common side effect and it carries the same risk for venous thrombosis as HRT.
The synthetic steroid derivative tibolone, has mild oestrogenic, progestogenic an androgenic properties.
The use of progesterone on its own, is not recommended for either the prevention or treatment of osteoporosis.
Plant or phyto-oestrogens may improve menopausal symptoms, but no data on the prevention of fractures are known.
Experimental data exist that testosterone has beneficial anabolic effects on bone tissue. Under certain circumstances, testosterone supplementation may be indicated in women.
Approximately one-third of men with osteoporosis has low levels of testosterone and requires replacement.
The bisphosphonates (e.g. alendronate, risedronate) are potent, extremely effective, non-hormonal anti-resorptive drugs which act directly on bone. They can reduce both spine and hip fracture rates by more than 50%.
Bisphosphonates are usually well tolerated, although upper gastro-intestinal side-effects occur in about 5-10% of patients. The drug should be taken with a full glass of water at least 30 minutes before having food or beverages and the patient should remain upright for this period.
Calcitonin is a naturally occurring hormone produced by the thyroid gland. It slows bone breakdown (resorption) and studies has shown that it decreases the rate of vertebral fractures. It is administered by injection or as a nasal spray and has an added benefit of providing pain relief - it is therefore often used in the treatment of acute fractures.
Formation Stimulating Drugs
Fluoride is administered as a slow- release enteric coated formulation. Side-effects include gastric irritation and joint pains. Response to therapy varies and treatment with this drug should best be done by an expert. Adequate calcium and vitamin D should always be taken with this drug.
Anabolic steroids are synthetic derivatives of the male hormone testosterone. They stimulate bone formation, decrease bone resorption and improve muscle strength. These agents are usually reserved for the short term (< 12 months) treatment of patients with advanced osteoporosis, especially the frail and elderly where muscle strength is impaired. Side effects (masculinisation in females, water retention and abnormal liver functions) appear to depend on the cumulative dose as well as individual sensitivity.
This drug has been available in South Africa for the past year and also stimulates bone formation and inhibits bone resorption. It increases bone mass and bone strength and significantly reduces the risk of hip and spine fractures. Parathyroid hormone (PTH 1-34) is given as a daily sub-cutaneous injection for 18 months. It is unfortunately very expensive and used to treat severe osteoporosis.
Statins (cholesterol lowering drugs) may stimulate bone-formation. Further studies are needed before these drugs can be used to treat osteoporosis.
Strontium ranelate stimulates bone formation and inhibits bone resorption – thus increasing bone mass and bone strength. This drug has few side effects and is one of the new drugs registered in this country to treat osteoporosis.
The lifestyle adaptations discussed in the prevention of osteoporosis is just as important in the treatment of osteoporosis i.e. exercise, a calcium rich balanced diet, stop smoking and limit alcohol intake.
If you have osteoporosis, you may be wondering whether you should exercise at all. Certain exercises can safely strengthen your back and stomach muscles, as well as help to maintain normal flexibility and balance. Check with your doctor or physiotherapist before embarking on your own exercise programme.
* Trade names of available drugs
- SERM’s/Raloxifene (Evista)
- Tibolone (Livifem)
- Bisphosphonates (Actonel, Fosamax, Osteobon)
- Calcitonin (Miacalcic)
- Fluoride (Ossiplex Retard)
- Parathroid Hormone (Forteo)
- Strontium (Protos)
(Reviewed by Tereza Hough, CEO, National Osteoporosis Foundation of South Africa. Click here to visit the website of NOFSA.)