Bisphosphonates

Risedronate (trade name Actonel), alendronate (Fosamax) and disodium etidronate (Didrocal).

• These drugs reduce your risk of fracture by increasing bone density and reducing the turnover of bone. On average, these drugs lead to an increase in bone density by approximately 4-8% at the spine and 1-3% at the hip over the first 3-4 years of treatment.
• In clinical trials involving people with osteoporosis, bisphosphonates have been shown to reduce the incidence of spinal fractures by as much as 30- 40% and in the hip by as much as 30-50%.
• Bisphosphonates are the best-studied drug treatment for men with osteoporosis. Stopping smoking and reducing excessive alcohol intake is also recommended.
• Bisphosphonates have also been shown to protect against the development of osteoporosis in people who are taking corticosteroids (e.g. cortisone, prednisone) for other medical conditions.
• Side effects are generally few, but can include pain with swallowing, upper gastrointestinal effects and indigestion. It is important to take these medications with the recommended amount of water, and stay upright for 30 minutes after taking the medication to avoid the rare complications of ulcers and erosions in your oesophagus.
• Fosamax Plus is Foxamax with vitamin D. Actonel Combi is Actonel with calcium. Actonel Combi D is Actonel with both calcium and vitamin D.

Generally, bisphosphonates should be taken first thing in the morning on an empty stomach with a glass of water. You should remain upright for half an hour after taking them and not eat or drink anything else in that half hour. As well, calcium supplements and oral bisphosphonates should be taken at least two hours apart. Otherwise the absorption of one can interfere with the other.

Strontium Ranelate

Protos

• Strontium ranelate (protos) is an agent for the prevention of fractures in post-menopausal women with osteoporosis.
• It has a dual action - increasing bone formation and decreasing bone resorption.
• It reduces vertebral fractures by 50%, non-vertebral fractures by 16% and reduces hip fractures by 19%
• It is a once daily dose, taken as a powder mixed with water. It is best taken at bed-time, at least 2 hours after food, calcium-containing products or antacids.
• Possible side-effects include nausea, diarrhoea, headache and skin irritation.
• An uncommon side effect is a blood clot in the vein (thrombosis) so if you experience pain or swelling in the legs or unusual or sudden shortness of breath, see your doctor immediately.
• A very rare side effect of strontium ranelate is drug hypersensitivity syndrome which causes a fever and/or rash and can affect other organs. See your doctor immediately if a fever and/or rash occurs whilst taking this medication.

Hormone Replacement Therapy (HRT)

• Oestrogen therapy can prevent bone loss in post-menopausal women and reduce fracture risk.
• However, because HRT has been associated with a small relative increase in the incidence of cardiovascular disease (heart attack and stroke) and breast cancer, it is not recommended for management of fracture risk alone, as this would require long-term use.
• HRT is appropriate for short term relief of menopausal symptoms (up to 5 years) and may have a role in preventing bone mineral density loss in women who have these symptoms.
• Its use is most appropriate in women under 60 years of age.
• In men with low levels of testosterone (hypogonadism), hormone treatment also increases bone density.

Selective Oestrogen Receptor Modulators (SERMs)

Raloxifene (trade name: Evista).

• This class of drugs works in a way that is either similar to or opposite to oestrogen, depending on which organ the drug is acting on. In bone it acts like oestrogen to reduce bone loss.
• Raloxifene reduces the incidence of spinal fractures by up to 50% but has not been demonstrated to reduce the risk of hip non-spinal fractures.
• Unlike HT, Raloxifene can worsen the symptoms of menopause.
• Raloxifene has also been demonstrated to reduce the risk of invasive breast cancer in post-menopausal women on long term therapy (greater than 5 years) without increasing the risk of endometrial cancer. However, there is an increased risk of clots and fatal stroke.
• An increased risk of venous thrombosis (clotting) has been reported with raloxifene, similar to that seen with HT, so if you are immobilised for a prolonged period your doctor will probably advise you to stop it.

Other Agents

Teriparatide (Forteo)

• Parathyroid hormone (teriparatide) stimulates bone formation and increases bone density and strength.
• Spine bone density has been shown to increase by up to 10% in some people and in studies of postmenopausal women with prior spinal fractures, has shown a reduction in the incidence of spinal (65%) and non-spinal (55%) fractures.
• Forteo is available in Australia for people with established osteoporosis who have had fractures when other drugs are considered unsuitable. It is currently not listed on the PBS (Pharmaceutical Benefits Scheme).
• Side-effects include dizziness and leg cramps.

On the horizon

Zoledronic Acid (Aclasta)

• It is a bisphosphonate in the form of a once yearly infusion.
• It is not PBS listed.