Seeking relief from the flu, this patient self-medicated with tetracycline, which was originally prescribed for his son's acne vulgaris. Expired tetracycline is a known cause of Fanconi's syndrome, a hereditary or acquired disorder of the proximal tubule of the kidney. This leads to defective transport of certain substrates, including glucose, amino acids, sodium, potassium, phosphate, uric acid, and bicarbonate. Characteristic findings include glucosuria, phosphaturia, proteinuria, polyuria, dehydration, hypercalciuria, and hypokalemia. Bicarbonate wasting can lead to renal tubular acidosis, while phosphate wasting can disrupt vitamin D metabolism and bone mineralization. This can result in rickets or impaired growth in children, and osteomalacia, osteoporosis, and pathologic fractures in adults.