Alendronic Acid

1 medicine

Alendronic acid is a bisphosphonate that slows bone loss to treat and prevent osteoporosis. It must be taken with a full glass of plain water while staying upright for 30 to 60 minutes, to avoid injuring the oesophagus.

Fosamax

Alendronic acid

35/70mg

Fosamax is a bone support medication containing Alendronic acid, available as 35/70mg tablets.

from $2.55 / tablet View

Key facts

  • Alendronic acid is a bisphosphonate. It slows the cells that break down bone, helping bone density hold steady or improve and lowering fracture risk.
  • It is taken once weekly or once daily, first thing in the morning, on an empty stomach, with a full glass of plain water only.
  • After taking it you must stay fully upright, sitting or standing, and eat nothing for at least 30 to 60 minutes. Lying down or eating too soon can let the tablet injure the oesophagus.
  • Seek urgent care for chest pain, new or worsening heartburn, or pain on swallowing, and tell your dentist you take it before any tooth extraction or implant work.

What alendronic acid treats

Alendronic acid treats and prevents osteoporosis, a condition where bones lose density and become fragile, in postmenopausal women, in men, and in people taking long-term corticosteroids. Slowing bone loss reduces the risk of fractures, particularly of the hip, spine, and wrist.

How alendronic acid works

Bone is constantly broken down and rebuilt by two types of cells working in balance. Alendronic acid binds to bone mineral and is taken up by the cells that break bone down, slowing their activity. With less bone removed than replaced, bone density stabilises or improves over months of treatment.

Before you take it

  • Do not take alendronic acid if you cannot sit or stand upright for at least 30 minutes, if you have low blood calcium, or if you have certain oesophagus problems that delay emptying.
  • Tell your dentist and prescriber before any planned tooth extraction, dental implant, or jaw surgery.
  • Take it with plain water only. Coffee, juice, mineral water, and food all reduce how much of the dose your body absorbs.
  • Ensure you get enough calcium and vitamin D from diet or supplements, since low levels can affect how the medicine works.

Side effects

Common effects include stomach upset, heartburn, and muscle or joint aches.

Stop and seek urgent medical care for any of these:

  • Chest pain, new or worsening heartburn, or pain or difficulty swallowing.
  • Jaw pain, swelling, or numbness, especially after dental work.
  • Unusual thigh or groin pain that develops gradually.
  • Signs of a severe allergic reaction, such as facial swelling or difficulty breathing.

Safety essentials

  • Always take alendronic acid with a full glass of plain water and remain upright for 30 to 60 minutes afterward. Failing to do this can cause irritation, ulceration, or injury to the oesophagus.
  • Long-term use is linked to osteonecrosis of the jaw, a rare condition where jaw bone tissue breaks down, most often after dental extractions or implants. Have dental work planned or completed before starting treatment where possible.
  • Long-term use is also linked to atypical femur fractures, unusual breaks in the thigh bone that can happen with little or no trauma. Report new hip, groin, or thigh pain to your prescriber promptly.
  • Your prescriber may reassess the need for ongoing treatment after several years, since the balance of benefit and risk changes with duration of use.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.