Alendronate plus vitamin D

Also called Fosamax Plus

Key points about alendronate plus vitamin D

  • Alendronate plus vitamin D is used to treat and prevent conditions affecting bones such as osteoporosis.
  • Alendronate plus vitamin D is also called Fosamax Plus.
  • Find out how to take it safely and possible side effects.
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Alendronate plus vitamin D is used to treat osteoporosis. Osteoporosis is a condition that causes your bones to be thinner and weaker than normal. This means that they can fracture (break) easily, such as after a small bump or fall. In osteoporosis alendronate prevents bone loss, increases bone thickness and lowers your risk of spine and hip fractures. Vitamin D is added because alendronate works best when you have enough vitamin D in your body.

In New Zealand alendronate plus vitamin D is available as tablets called Fosamax Plus. Alendronate belongs to a group of medicines known as bisphosphonates.

Watch a video about alendronate for osteoporosis.

(RheumInfo(external link), Canada, 2019)

  • The usual dose of alendronate plus vitamin D is 1 tablet ONCE A WEEK (every 7 days).
  • Always take your alendronate plus vitamin D exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it and any special instructions.

It is very important that you carefully follow the instructions of how to take alendronate safely. If not taken properly, alendronate can irritate or burn your food pipe (or oesophagus).  



  • Take alendronate plus vitamin D on the same day each week. To help you remember, choose a day that best suits your routine, eg, every Monday.
  • Take alendronate first thing in the morning, before eating or drinking anything else, including other medicines. Do not take your dose at bedtime or while lying in bed.
  • Take your tablet with a full glass of water. Do not take it with mineral water, tea, coffee, milk or juice, as these interfere with the absorption of alendronate into your body. 


Stay upright for at least 30 minutes after taking your dose

  • Swallow the tablet whole – do not crush or chew. You may get mouth ulcers if you chew or dissolve the tablet in your mouth.
  • Stay upright for at least 30 minutes after taking your dose. Do not lie down for at least 30 minutes, and do not have any food, drinks or medicines during this time. 
  • If you are unwell and cannot sit or stand upright for 30 minutes after taking your dose, skip that day’s dose and do not take it until you are feeling better. Contact your doctor or pharmacist if you need to miss more than 2 or 3 doses.


Missed dose

If you forget to take your dose, just take it the next morning. Then take 1 tablet once a week, as before.

  • Do you have any difficulties swallowing?
  • Are you unable to sit upright for at least 30 minutes?
  • Have you had a stomach ulcer, stomach bleeding or any surgery on your upper digestive system within the past year?
  • Are planning to have any dental treatment in the near future or do you have problems with your teeth?
  • Do you have any problems with the way your kidney works?
  • Are pregnant or breastfeeding?
  • Are you taking any other medicine (including over-the-counter and herbal products)?

If so, it’s important that you tell your doctor before you start taking alendronate plus vitamin D. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

Like all medicines, alendronate plus vitamin D can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.


Problems with your jaw

Alendronate plus vitamin D can cause osteonecrosis of the jaw. This can be caused by delayed healing in your mouth after some dental procedures. This is quite rare. To reduce the risk of this problem, it is best to take the following steps:

  • Take good care of your teeth and mouth (such as brushing your teeth twice a day and regular flossing between your teeth).
  • Have regular dental check-ups.
  • If you need any dental treatment, it is best that you have this done before you start treatment with alendronate.
  • Let your dentist know that you are taking alendronate.
  • Talk to your doctor or dentist if you have any loose teeth, tooth pain, swelling or numbness in your jaw.



Alendronate plus vitamin D can rarely cause fractures (breaks) in your thigh bone (upper leg bone). These are called atypical fractures because they appear as cracks on the bone and are not usually related to an injury. If you have pain, weakness or discomfort in your thigh, hip or groin, tell your doctor. These may be warnings that there is some weakness in your bones. You may need x-rays of your legs.


Other side effects

Side effects What should I do?
  • Bloating (gas in the tummy)
  • Nausea (feeling sick)
  • Diarrhoea (runny poos)
  • These are common when you first start taking alendronate.
  • Tell your doctor if troublesome.
  • Difficulty swallowing or pain when swallowing
  • Heart burn or indigestion
  • Chest pain
  • Stop taking alendronate and tell your doctor immediately or phone HealthLine 0800 611 116.
  • Eye pain
  • Red eye
  • Changes in your vision
  • Sensitive to light
  • Floating spots in your vision
  • These symptoms are related to inflammation in the eye. This is quite rare.
  • Contact your doctor immediately if you experience these symptoms. 
Did you know that you can report a side effect of a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product(external link)

Alendronate plus vitamin D may interact with a number of medicines, including herbal supplements, so check with your doctor or pharmacist before starting alendronate or before starting any new medicines. Some medicines available without a prescription may interact with alendronate, such as calcium supplements, iron supplements and antacids. 

Alendronic acid and colecalciferol(external link) NZ Formulary Patient Information
Fosamax Plus(external link) Medsafe Consumer Information Sheets

  1. Alendronic acid + colecalciferol(external link) NZ Formulary [accessed December 2019] 
  2. Osteoporosis treatments and atypical femur fracture(external link) Medsafe Prescriber Update 34(1): 5-6 March 2013
  3. Osteonecrosis – a pain in the jaw(external link) Medsafe Prescriber Update 33(2): 13-14 June 2012
  4. Osteonecrosis of the jaw and bisphosphonates – putting the risk in perspective(external link) Medsafe Publications, October 2007
  5. Reminder – keeping an eye on bisphosphonates(external link) Medsafe Prescriber Update 32(3): 24 September 2011
  6. An update on bisphosphonates(external link) BPAC, NZ, 2014
  7. Fosamax(external link) Medsafe Datasheet

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Credits: Sandra Ponen, Pharmacist. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland

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