Drug side effects
alendronate Side Effects
The reactions most often reported to the FDA for alendronate (also sold as Fosamax), with demographics, serious outcomes, and reporting trends.
Data updated 2026-05-15
- 98,033
- FAERS reports
Data from the FDA Adverse Event Reporting System (FAERS), 2003 to 2025. A FAERS report records a temporal association, not proof of cause. See our methodology for how figures are compiled and de-duplicated.
The most commonly reported side effects of alendronate come from 98,033 reports to the FDA, broken down here by frequency, patient demographics, and serious outcomes.
This page analyzes 98,033 reports to the FDA Adverse Event Reporting System (FAERS) for alendronate (Fosamax): the reactions reported most often, who reported them, serious outcomes such as hospitalization, and year-over-year trends. A FAERS report does not prove the drug caused the effect, and report volume tracks how widely a drug is used, not how likely an effect is for any one person. Educational information, not medical advice.
Total Reports
98,033
Reports Mentioning Death
11,123
11.3% of reports — not proof the medicine caused the death
Hospitalizations
36,609
37.3% of reports
Top Indication
Osteoporosis
Most Reported Adverse Reactions
Who Reports Side Effects
Gender Distribution
Age Distribution
Reporting Trend by Year
Reactions in Death Reports
Top reactions reported in 11,123 reports where death was an outcome. These are voluntarily reported and do not establish causation.
| Reaction | Reports |
|---|---|
| DEATH | 2,940 |
| FATIGUE | 2,297 |
| HYPERTENSION | 2,233 |
| GENERAL PHYSICAL HEALTH DETERIORATION | 2,175 |
| SYSTEMIC LUPUS ERYTHEMATOSUS | 2,129 |
| TYPE 2 DIABETES MELLITUS | 2,102 |
| GLOSSODYNIA | 2,095 |
| RHEUMATOID ARTHRITIS | 2,088 |
| ARTHRALGIA | 2,061 |
| HYPOAESTHESIA | 2,058 |
| INFUSION RELATED REACTION | 2,045 |
| HAND DEFORMITY | 2,040 |
| RASH | 2,028 |
| FIBROMYALGIA | 2,018 |
| PSORIATIC ARTHROPATHY | 2,017 |
| DUODENAL ULCER PERFORATION | 1,996 |
| WOUND | 1,994 |
| HELICOBACTER INFECTION | 1,989 |
| DIARRHOEA | 1,982 |
Reactions in Hospitalization Reports
Top reactions in 36,609 reports where hospitalization was an outcome.
| Reaction | Reports |
|---|---|
| FEMUR FRACTURE | 6,662 |
| FALL | 6,341 |
| ARTHRALGIA | 5,721 |
| HYPERTENSION | 5,409 |
| FATIGUE | 5,117 |
| PAIN | 5,096 |
| OSTEOARTHRITIS | 4,674 |
| DYSPNOEA | 4,329 |
| RHEUMATOID ARTHRITIS | 4,199 |
| NAUSEA | 4,122 |
| ARTHROPATHY | 3,901 |
| DIARRHOEA | 3,890 |
| RASH | 3,877 |
| PAIN IN EXTREMITY | 3,777 |
| PNEUMONIA | 3,774 |
| HEADACHE | 3,746 |
| IMPAIRED HEALING | 3,584 |
| DEPRESSION | 3,553 |
Nearby, Related Medications
What the FAERS Data Reveals About alendronate Side Effects
The FDA Adverse Event Reporting System (FAERS) contains 98,033 voluntary reports linked to alendronate and its brand equivalents (Fosamax), spanning 2003 through 2025. Of those, 11,123 (11.3%) listed death as an outcome and 36,609 (37.3%) involved hospitalization. The most common indication reported alongside adverse events was Osteoporosis.
Demographic breakdowns help contextualize who is being exposed to the drug. Of reports with known sex, 86% were female and 14% male; age distribution skews toward 45-64, with 18,310 reports in that bracket. The single most reported reaction is pain with 13,527 submissions, followed by fatigue and femur fracture.
How to read these numbers
FAERS is a signal-detection tool, not a scorecard. Reports are voluntary, and a single case may list multiple suspect drugs, so numbers above should not be read as incidence rates or per-patient risk. Widely prescribed drugs naturally accumulate more reports than niche therapies even when individual risk is low. These aggregates are useful for spotting patterns that merit further pharmacovigilance, not for choosing between medications. This page is for educational reference only and is not medical advice, speak with a licensed clinician about any side-effect concerns.
Drugs With a Similar FAERS Report Volume
Other medications with a total FDA adverse-event report count closest to alendronate's 98,033.
Read our methodology - how this data is sourced, computed, and verified.