Megaloblastic Anemia Associated with Long-Term Tetracycline Therapy

An 18-year-old woman developed a sore mouth and a megaloblastic anemia while treated with tetracycline, 500 mg daily, for 3 years. Folate deficiency was found, and the anemia responded promptly to oral folic acid therapy. She had no evidence of vitamin B12 malabsorption and no history or clinical findings suggesting dietary lack of folate, malabsorption syndrome, increased folate requirements, or offending drug intake other than tetracycline. All possible tests for an occult malabsorption were not done.