Alendronate — NZ Medication Guide
📋 Reviewed by a Registered Pharmacist NZ — This information is for general educational purposes only and does not replace professional medical advice. Always consult your doctor or pharmacist before starting, stopping, or changing any medication.
What is Alendronate?
Alendronate (alendronic acid) is a bisphosphonate used primarily for the prevention and treatment of osteoporosis. This medication is commonly prescribed in New Zealand and is funded by Pharmac for osteoporosis treatment.
What is Alendronate Used For?
Alendronate is prescribed for postmenopausal osteoporosis, glucocorticoid-induced osteoporosis, and Paget’s disease of bone. It significantly reduces the risk of fractures — including hip, spine, and wrist fractures.
How Does Alendronate Work?
Alendronate inhibits osteoclast-mediated bone resorption by binding to hydroxyapatite in bone tissue and impairing osteoclast activity. This shifts the bone remodelling balance towards formation, increasing bone mineral density and reducing fracture risk over time.
How to Take Alendronate
Taken as a once-weekly tablet (70 mg), swallowed whole with a full glass of plain water (at least 200 mL) on an empty stomach, first thing in the morning — at least 30 minutes before any food, drink (other than water), or other medicines. Remain upright (sitting or standing) for at least 30 minutes after taking to reduce the risk of oesophageal irritation.
Common Side Effects of Alendronate
- Oesophageal irritation or heartburn (if not taken correctly)
- Nausea or abdominal discomfort
- Musculoskeletal pain (bones, joints, muscles)
- Headache
Serious Side Effects — Seek Medical Attention
Contact your doctor or call 111 immediately if you experience any of the following:
- Oesophageal ulceration or erosion (if lying down after dose or in patients with pre-existing oesophageal problems)
- Osteonecrosis of the jaw (rare — associated with dental procedures, particularly in cancer patients on IV bisphosphonates)
- Atypical femoral fractures (rare — with very long-term use)
- Severe hypocalcaemia (rare — ensure adequate calcium and vitamin D)
- Severe musculoskeletal pain (rare)
Drug Interactions
Alendronate may interact with other medicines. Always inform your doctor and pharmacist of all medications, supplements, and herbal products you are taking. Key interactions include:
- Calcium supplements, antacids, and dairy products (reduce alendronate absorption — must be taken separately by at least 30 min)
- NSAIDs (increased gastrointestinal risk)
- Aspirin
New Zealand Prescribing Information
Alendronate 70 mg once-weekly tablets are funded by Pharmac for the treatment of postmenopausal osteoporosis and glucocorticoid-induced osteoporosis. In New Zealand, patients at high fracture risk may be assessed using the FRAX tool or a DXA (bone density) scan. Calcium and vitamin D supplementation is recommended alongside alendronate.
Frequently Asked Questions
Why do I have to stay upright after taking alendronate?
Alendronate can irritate and potentially ulcerate the oesophagus if it remains in contact with the oesophageal lining. Remaining upright (sitting or standing) for at least 30 minutes ensures the tablet passes quickly into the stomach, minimising irritation.
How long do I need to take alendronate?
Most guidelines recommend 3–5 years of treatment, after which a drug holiday may be considered based on your fracture risk and bone density results. Your doctor will review the benefits and risks of continuing treatment at regular intervals.
⚠️ Disclaimer: This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or a qualified health provider with any questions you may have regarding a medical condition or medication. In New Zealand, medication availability and funding may vary — check with Pharmac or your pharmacist for the most current information.
Reviewed by a Registered Pharmacist NZ
References & Further Information
The following New Zealand and international resources were used to inform this page: