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Bisphosphonates

Bisphosphonates are a family of drugs used to prevent and treat osteoporosis. There are four bisphosphonates currently approved for use in Canada: alendronate (Fosamax ®), etidronate (Didrocal ®), risedronate (Actonel ®) and zoledronic acid (Aclasta®. Also available are: Actonel® Plus Calcium and Fosavance® (Fosamax® with vitamin D).

How do they work?

Bisphosphonates bind to the surfaces of the bones and slow down the bone resorping action of the osteoclasts (bone-eroding cells). This allows the osteoblasts (bone-building cells) to work more effectively.

How effective are they?

All four bisphosphonates increase bone density and prevent fractures of the spine (vertebral fractures). Alendronate, risedronate and zolendric acid have also been shown to prevent hip fractures. 

Who can take them?

Bisphosphonates are used to treat osteoporosis in: postmenopausal women and in men; and in men and women of any age who are using steroid medications.

How are they taken?

There are very specific instructions about how bisphosphonates must be taken. Following the directions will allow your body to absorb the drug properly and may help you avoid side effects. Because calcium interferes with the absorption of bisphosphonates, calcium supplements must be taken at other times of the day. See table below.

Are there side effects?

The most common side effects are nausea, abdominal pain and loose bowel movements. Bone, joint and/or muscle pain has been reported in patients taking bisphosphonates; such reports have been infrequent. There is a small risk of ulcers in the esophagus with both alendronate and risedronate, especially if taken incorrectly. The most common side effects of zoledronic acid, which usually only last a day or two, are fever, pain in the muscles, bones or joints, flu-like symptoms and headache. There have been rare cases of acute renal dysfunction following infusions of zoledronic acid. 

 In very rare cases, alendronate, risedronate and zoledronic acid have been linked to a breakdown of the jaw bone (called osteonecrosis of the jaw) following dental surgery such as dental extractions. Rare cases of atypical fractures of the femoral (thigh) bone have been reported with bisphosphonates. Notify your physician if you experience pain in the groin or thigh that is present for a few weeks. Read more>>

How to take a bisphosphonate

  Frequency Time of day Instructions
Alendronate (Fosamax®),
10 mg (treatment)
every day first thing in morning, at least 1/2 hour before eating

Take with 250ml (8 oz) plain water

Don't lie down for 1/2 hour AND until after the first food of the day

 

Alendronate
(Fosamax®)
 70 mg
(Fosavance®)
70 mg + 2800 IU vitamin D or
70 mg + 5600 IU vitamin D
once a week same as above

same as above

Etidronate (Didrocal®)
400 mg
every day for two weeks followed by 10 weeks (76 days) of 500 mg calcium supplements (provided in package) White etidronate tablet: mid morning, mid afternoon or evening (at least two hours before and after eating)
Blue calcium tablet: anytime, but best taken with food

Take with a glass of water

No calcium supplements/ vitamins for two hours before or after

Risedronate (Actonel®)
5 mg
every day first thing in morning, at least 1/2 hour before eating

Take with 125ml (4 oz) water

Don't lie down for 1/2 hour AND until after the first food of the day

 

Risedronate (Actonel®)
35 mg
(Actonel® Plus Calcium) 35 mg
+ 500 mg elemental calcium
once a week




Actonel® Plus Calcium:
calcium carbonate 6 days/week
first thing in morning, at least 1/2 hour before eating



The calcium tablet: anytime but best taken with food

Risedronate tablet: Take with a glass of water

Don't lie down for 1/2 hour AND until after the first food of the day

 

Risedronate (Actonel®)
150 mg
once a month first thing in morning, at least 1/2 hour before eating

Take with a glass of water

Don't lie down for 1/2 hour AND until after the first food of the day

Zolendric acid (Aclasta®)
5 mg
once a year not applicable

Given as a 15-minute intravenous (IV) infusion by a certified healthcare professional