Hair Loss with Fosamax (Alendronate)
Hair loss is not a documented adverse effect of Fosamax (alendronate) based on available clinical trial data and systematic reviews.
Evidence from Clinical Trials
The extensive clinical trial experience with alendronate does not identify hair loss as an adverse event:
Large-scale trials in postmenopausal women involving over 10,000 participants in primary prevention studies and over 7,000 in secondary prevention studies did not report hair loss as an adverse event 1
Studies in men with osteoporosis (241 participants over two years) documented upper gastrointestinal effects and musculoskeletal pain as the primary adverse events, with no mention of alopecia 2
Glucocorticoid-induced osteoporosis trials (477 participants over 48 weeks) reported only nonserious upper gastrointestinal effects as the main tolerability concern, without documenting hair loss 3
Documented Adverse Event Profile
The established adverse events associated with alendronate include:
Upper gastrointestinal tract effects are the most common, including abdominal pain, nausea, dyspepsia, and acid regurgitation 4
Musculoskeletal pain occurs but shows no statistically significant difference from placebo in large trials 4
Serious adverse events show no clinically important increase compared to placebo (relative risk 1.08 in primary prevention, 0.75 in secondary prevention) 1
Clinical Context
The provided evidence extensively discusses hair loss in the context of other medications (particularly acitretin, where hair loss occurs in up to 75% of patients) 5, but none of the alendronate-specific studies or systematic reviews document alopecia as an adverse effect 4, 6, 2, 1, 3.
Important Caveats
Postmarketing surveillance has identified rare esophageal adverse events not detected in clinical trials, suggesting that very rare effects may exist 4
If a patient reports hair loss while taking alendronate, alternative causes should be investigated including thyroid dysfunction, nutritional deficiencies, autoimmune conditions, or other medications 7
The absence of reported hair loss in clinical trials involving thousands of patients over multiple years provides strong evidence against a causal relationship 1