Alendronate vs Zoledronic Acid: side effects in FDA adverse event reports
At a glance
| Alendronate | Zoledronic Acid | |
|---|---|---|
| Drug class | – | – |
| Brand names | Alendronate Sodium | – |
| FAERS reports | 100,301 | 39,894 |
| Serious | 78% | 87% |
| Death outcome | 11,882 | 5,134 |
| Boxed warning | No | No |
Signals both drugs share
No strong shared signal after removing coding and lab terms.
Labeled signals distinctive to Alendronate
- Femur fracture — n=11,361, PRR 120.9 Labeled adverse reaction
- Duodenal ulcer perforation — n=4,964, PRR 446.5 Labeled (related wording)
- Peripheral venous disease — n=1,436, PRR 117.6 Labeled (related wording)
- Fracture delayed union — n=439, PRR 223.6 Labeled (related wording)
Labeled signals distinctive to Zoledronic Acid
- Osteonecrosis of jaw — n=2,708, PRR 64.0 Labeled (related wording)
- Exposed bone in jaw — n=247, PRR 66.7 Labeled (related wording)
- Atypical femur fracture — n=247, PRR 50.1 Labeled adverse reaction
- Iridocyclitis — n=161, PRR 28.5 Labeled adverse reaction
- Acute phase reaction — n=129, PRR 278.2 Labeled adverse reaction
- Atypical fracture — n=51, PRR 47.6 Labeled adverse reaction
- Idiopathic orbital inflammation — n=46, PRR 167.6 Labeled (related wording)
- Respiratory tract infection bacterial — n=27, PRR 29.9 Labeled (related wording)
Common questions
Which has more reported side effects, Alendronate or Zoledronic Acid?
Alendronate has 100,301 FAERS reports and Zoledronic Acid 39,894. More reports does not mean more dangerous: volume follows how widely and how long a drug has been used, prescription vs over-the-counter status, and publicity. The seriousness share (78% vs 87%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Alendronate and Zoledronic Acid share?
They share no strong flagged signal after artifacts and lab terms are removed.
Is Alendronate or Zoledronic Acid safer?
FAERS cannot answer that: it has no denominator and no comparator. Use this page to see which risks are already on each label and which signals are unlabeled, then check the prescribing information and your clinician for your situation.
Sources: openFDA FAERS pair statistics (OpenPV build 2026-09-14), FDA labels via openFDA, openFDA count queries for seriousness and deaths. Pair chosen because it is a commonly searched comparison. Generated 2026-10-08.