Alendronic Acid
Also known as: Alendronate, Fosamax
What it's for
Alendronic acid strengthens bones and prevents fractures in osteoporosis. It slows bone loss and is usually taken once weekly. Proper technique is important.
Comes as: Tablets
How to take it
- Adults: Usually 70mg once a week, or 10mg once daily.
- Take first thing in the morning on an empty stomach.
- Swallow whole with a full glass of plain water (not mineral water).
- Stay upright (sitting or standing) for at least 30 minutes after taking.
Doses here are typical. Always follow the instructions from your prescriber or on the packet — they come first.
Common side effects
- Stomach pain, heartburn, or indigestion
- Feeling sick
- Headache
- Muscle or joint pain
The leaflet inside the packet lists all known side effects.
Important safety points
- Must take on an empty stomach with plain water only
- Stay upright for 30 minutes - do not lie down
- Do not take at bedtime or before getting up
- Tell your dentist you take this before any dental work
Get medical help urgently if…
- You have severe heartburn or difficulty swallowing
- You have jaw pain or numbness
- You have unusual thigh or hip pain
- You have chest pain or new stomach pain
Call NHS 111 for urgent advice, or 999 if someone is seriously unwell.
Before you act on anything here
This page is general information, written to help you understand — it is not personal medical advice and it cannot tell you what is right for you. Talk to your own GP, pharmacist or nurse about your own health.
- Need help now but it's not an emergency? Call NHS 111 or use 111.nhs.uk.
- Emergency? Call 999 or go to A&E.