About

Alendronic acid (also known as alendronate) is a medicine used to strengthen bones and reduce the risk of fractures. It belongs to a class of drugs called bisphosphonates, which work by slowing down the cells that break down bone (osteoclasts), helping to maintain bone density and strength.

It is commonly prescribed for:

• Osteoporosis in postmenopausal women
• Osteoporosis in men
• Prevention of steroid-induced osteoporosis
• Paget’s disease of bone

Alendronic acid is usually available in the form of:

• Tablets (10 mg daily or 70 mg once weekly)
• Effervescent or soluble tablets
• Oral solution (in some formulations)

How and When to Use It

Take alendronic acid exactly as prescribed by your doctor.

Dosage: The most common dose is one 70 mg tablet once weekly, or one 10 mg tablet daily.

Take your dose first thing in the morning, on an empty stomach, with a full glass (at least 200 mL) of plain water.

After taking alendronic acid:

• Remain upright (sitting or standing) for at least 30 minutes.
• Do not eat, drink (except water), or take any other medicines during this time.

This helps prevent irritation of the oesophagus and ensures proper absorption.

Continue to take it regularly for as long as your doctor recommends.

Contraindications

Alendronic acid should not be used if you have:

• Allergy to alendronic acid or any of its ingredients
• Problems with the oesophagus (e.g., narrowing or difficulty swallowing)
• Low blood calcium levels (hypocalcaemia)
• Inability to stand or sit upright for at least 30 minutes
• Severe kidney disease

Side Effects

Like all medicines, alendronic acid can cause side effects, although not everyone gets them.

Common side effects:

• Stomach pain or indigestion
• Constipation or diarrhoea
• Muscle or joint pain
• Heartburn or irritation of the oesophagus

Rare but serious side effects:

• Severe oesophageal irritation or ulcers
• Jaw bone problems (osteonecrosis, especially after dental procedures)
• Unusual thigh bone fractures (with long-term use)
• Allergic reactions (rash, swelling, difficulty breathing)

Seek medical help if you experience chest pain, new or worsening difficulty swallowing, or severe bone, joint, or muscle pain.

Pregnancy, Breastfeeding & Fertility

Alendronic acid is not usually recommended during pregnancy or breastfeeding. If you are pregnant, planning to become pregnant, or breastfeeding, speak to your doctor before taking this medicine.

There is limited information about its effects on fertility, but it is not expected to cause harm when used appropriately.

Interactions With Other Medications

Some medicines and supplements can interfere with the absorption or effects of alendronic acid:

• Calcium, iron, magnesium, or antacids (reduce absorption — take at least 30 minutes after alendronate)
• Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (increase risk of stomach irritation)
• Corticosteroids (increase risk of bone or jaw complications)
• Other osteoporosis medicines (consult your doctor before combining)

Frequently Asked Questions