Alendronic Acid

Alendronic Acid is a type of medicine called a bisphosphonate. Bisphosphonates are class of drugs that prevent loss of bone mineral in bone tissue and used to treat osteoporosis. It helps your bones stay as strong as possible and less likely to break.

“In the UK, alendronic acid is licensed for the prevention of osteoporotic fractures and bone loss in women at doses of 10mg daily or 70mg weekly. However, only the daily formulation is licensed for use in women, and the drug is not indicated for prophylaxis against male bone loss at any dose. National Institute for Health and Clinical Excellence guidance, and guidance from the WHO, around the use of alendronic acid applies only to women. Evidence suggests that alendronic acid is effective in men, although possibly not to the same extent as in postmenopausal women.” (Clinical Pharmacist, 2012, Can weekly alendronic acid prevent osteoporotic fractures in men?, Vol. 4, p268)

It is also known as alendronate sodium or alendronate. Mostly prescribed brand name in the US is Fosamax while in the Philippines is Alendra. It is only available on prescription and often recommended together with vitamin D and calcium supplementation.

It usually starts to work after 1 month. However, it may take 6-12 months to fully protect your bones. It can be taken by adults aged 18 and above. Also, it is not recommended to children because of insufficient safety and data for pediatric osteoporosis. However, there is a study about the safety and efficacy of alendronic acid in the treatment of osteoporosis in children and adolescents.

“No patient had bone fractures or expressed adverse effects during treatment. Alendronate increased bone mineral density and was well tolerated in all patients, therefore it could be considered as a therapeutic option in the treatment of osteoporosis in children.” (Alberto Martin Siguero et al, 2015, Farm Hosp. Efficacy and safety of alendronic acid in the treatment of osteoporosis in children, 2015;39(6):350-357)

The usual dose for adults is 70mg taken once a week, or 10mg taken once a day. It comes as tablets, soluble tablets that dissolve in water to make a drink or as a liquid that you can drink. Take alendronic acid first thing in the morning, on an empty stomach with plain tap water not mineral water (not less than 200 ml or 7 fluid ounce) before you have anything to eat, drink or other medicines to take.

The reason why it should not be taken with mineral water is because the absorption of alendronate decreases based on the high levels of calcium concentration of mineral water. If it’s not safe to drink your tap water, you can boil the water and let it cool before drinking.

Alendronic acid works best when your stomach is empty and can be absorbed properly. Stay upright like sitting, standing or walking for 30 minutes after taking it. You can eat your first food of the day at least 30minutes after taking the tablet. It should not be crushed or chewed, or allow the tablet to dissolve in their mouths because of a potential for throat sores that can become red and swollen. They can make it hard for you to eat and talk.

Common side effects of alendronic acid in some people are constipation, diarrhea, vertigo (feeling dizzy), headache, muscle or joint pain, swollen joint (hands or legs), indigestion (bloating or wind), itching or a mild rash, feeling sleepy or tired and hair loss.

Some people when taking this have serious side effects like heartburn problems, pain when swallowing, or chest pain. This may indicate signs of ulcers or throat sores in your food pipe (esophagus). In this case you should stop taking it and see a doctor.

According to a study, “alendronic acid has a potent apoptotic (cell death) on oral epithelial cells and affect the integrity of dermis.” (Papamitsou Theodora et al, 2018, Journal of Dental and Oral Health: Effect of Alendronic Acid on Buccal Mucosa, vol.4, Issue 3, Issn:2369-4475).

Therefore, when taking alendronic acid, it’s important to look after your teeth and have regular dental check-ups because it can damage your jaw bone. It may bring mouth sores, a loose tooth, pain in your mouth or jaw but this happens rarely.

The risk is substantially greater for patients receiving intravenous bisphosphonates in the treatment of cancer than for patients receiving oral bisphosphonates for osteoporosis or Paget’s disease.

Pain, weakness, discomfort in your thigh, hip or groin and can be an early sign of broken thigh bone or atypical femoral fracture. This may happen but rarely in patients receiving long term treatment for osteoporosis.

Alendronic acid is not usually recommended during pregnancy and women who are breastfeeding because of insufficient research into its safety.

There are some medicines that may interfere with the absorption of alendronic acid:
  • Supplements or multivitamins containing calcium, iron, magnesium or zinc, antacids (to relieve indigestion or heartburn),
  • laxatives containing magnesium,
  • cancer medicines such as bevacizumab and thalidomide or if you are having chemotherapy and taking steroids such as prednisolone and dexamethasone- they may increase damage to your jaw bone,
  • non-steroidal anti-inflammatories (NSAIDs) such as Ibuprofen- can increase risk of irritating your food pipe (esophagus), stomach or gut but taking low-dose aspirin may be acceptable,
  • Antibiotics such as gentamicin, amikacin, or tobramycin- these can lower calcium in your blood and lastly
  • Deferasirox, a medicine used to remove excess iron from the body- this may increase the risk of bleeding in your gut.