Bisphosphonate Pregnancy: There are no or limited data from use in pregnant women and animal studies have shown reproductive toxicity — alendronate should not be used during pregnancy. It is unknown whether alendronate/metabolites are excreted in human milk and a risk to the newborn/infant cannot be excluded — should not be used during breast-feeding.

Alendronic Acid

Brand names: Fosamax, Binosto (effervescent)

Used in: Falls & Frailty

Alendronic acid is an oral nitrogen-containing bisphosphonate used as first-line treatment for osteoporosis and to reduce fragility-fracture risk, including in the orthopaedic and trauma setting after low-trauma fractures.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 70 mg (one tablet)

Route: Oral

Frequency: Once weekly

Source SPC is 'Alendronic Acid 70 mg Film-coated Tablets': 'The recommended dose is one 70 mg tablet per week.' MISSED DOSE: patients who forget the weekly tablet should take it the following morning after realising they have missed it; they must not take two tablets on the same day, and should continue with one tablet a week on the originally scheduled day. ADMINISTRATION (critical to absorption and oesophageal safety): must be taken on an empty stomach immediately on rising in the morning, with plain water only, at least 30 minutes before the first food, drink or other medication of the day; swallow whole with a whole glass of water (not less than 200 mL) — do not chew, suck or allow to dissolve in the mouth (risk of oropharyngeal ulceration); do not lie down until after the first meal of the day, which must be at least 30 minutes after taking the tablet; do not take at bedtime or before arising for the day. DURATION: the optimal duration of bisphosphonate treatment for osteoporosis has not been established — re-evaluate the need for continued treatment periodically on an individual basis, particularly after 5 or more years of use. Give a calcium and vitamin D supplement if the diet is inadequate. ELDERLY: no adjustment necessary. HEPATIC: no dose adjustment necessary. PAEDIATRIC (non-numeric — not structured): not recommended for use in children under 18 years due to insufficient data on safety and efficacy in paediatric osteoporosis. This product has not been investigated in the treatment of glucocorticoid-induced osteoporosis.

Dose adjustments

Renal

No dose adjustment is necessary in patients with a creatinine clearance greater than 35 mL/min. Alendronate is not recommended for patients with impaired renal function if the creatinine clearance is less than 35 mL/min, as there is no experience of this

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Oesophageal abnormalities and other factors that delay oesophageal emptying, such as stricture or achalasia
Inability to stand or sit upright for at least 30 minutes
Hypocalcaemia

Side effects

Upper gastrointestinal effects — abdominal pain, dyspepsia, acid regurgitation, constipation, diarrhoea, flatulence, abdominal distension (common); oesophageal ulcers, oesophagitis, oesophageal erosions and dysphagia, rarely followed by oesophageal stricture
Musculoskeletal pain (bone, muscle or joint) — reported in about 3% in the one-year study
Headache, dizziness and vertigo (common)
Alopecia and pruritus (common)
Osteonecrosis of the jaw (see §4.4); very rarely osteonecrosis of the external auditory canal (bisphosphonate class effect)
Rare: symptomatic hypocalcaemia (often with predisposing conditions), hypersensitivity reactions including urticaria and angioedema; uncommon eye inflammation (uveitis, scleritis, episcleritis)

Interactions

Other drinks (including mineral water), food and some medicines are likely to reduce the absorption of alendronate — take with plain water only, at least 30 minutes before the first food, drink or other medication of the day (§4.2, referring to §4.5)

Clinical monograph

How it works

It binds avidly to bone mineral and inhibits osteoclast-mediated bone resorption by interfering with the mevalonate pathway, reducing bone turnover and increasing bone mineral density.

Prescribing in practice

Take on rising on an empty stomach with plain water, remaining upright and not eating, drinking or taking other medicines for the advised period afterwards, to prevent severe oesophageal irritation and ulceration.
Correct vitamin D deficiency and hypocalcaemia before starting, and ensure adequate calcium and vitamin D intake during treatment.
Counsel on the rare risks of osteonecrosis of the jaw and atypical femoral fractures, with dental review before and during therapy and reporting of thigh or groin pain.

Monitoring

Monitor adherence, renal function and calcium/vitamin D status, and review the need for continued treatment with a drug-holiday assessment after a defined treatment period.

Counselling the patient

Swallow the tablet whole with a full glass of plain water and stay upright; do not lie down for the advised interval.
Report any difficulty or pain on swallowing, heartburn, new thigh or groin pain, or dental problems.

Evidence & guidelines

The Fracture Intervention Trial demonstrated reduced vertebral and hip fracture risk, and NICE recommends oral bisphosphonates as first-line osteoporosis therapy.

Reference: NOGG Osteoporosis Guidelines 2021; NICE TA160; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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