Dear editor, We read the article of Bereket and Ertogan [1], reporting a 3-month-old boy with vitamin D intoxication, who was treated with alendronate, with great interest. Here we present a 7-year-old male with acute vitamin D intoxication, who was treated with oral alendronate. A 7-year old male child was admitted to our Pediatric Emergency Unit with symptoms of anorexia, nausea, vomiting, polydipsia, polyuria and constipation. In history, he was administered 300,000 units of oral vitamin D (cholecalciferol) daily for 15 days by an internist, who suspected vitamin D deficiency. Above mentioned symptoms had occurred at the end of 15 days. The physical examination on admission revealed impaired turgor of the skin and dryness of the oral mucosa consistent with moderate dehydration. The rest of the examination was unremarkable. On admission, laboratory findings are shown in Table 1. The patient was admitted to the ward and emergency treatment was initiated with IV hydration (2,500 mL/m/d, additional 20 mEq/l potassium chloride), furosemide (1 mg/kg/dose, every 6 h). Dietary calcium and vitamin D intake were restricted. A repeat serum calcium level was 14.8 mg/dL on the following day. Urinary calcium/creatinine ratio was initially high. Renal ultrasonography was reported as normal. Alendronate sodium 5 mg/d given by mouth was added to treatment after obtaining informed consent from the father. Serum calcium was still 14.3 mg/dL on the 3rd day of admission, the dose of alendronate was increased to 10 mg/d. Calcium levels decreased gradually in the following days. Then serum calcium dropped to 10.3 mg/dL on the 16th day and treatment was discontinued without any relapse. No side effects were noted with this treatment. Serum calcium levels remained normal thereafter. Urinary calcium/creatinine ratio decreased gradually to normal levels on 2nd month. Renal ultrasound examination at 2nd month after the admission did not show any evidence of nephrocalcinosis or other abnormalities. A radiographs of the hand taken on the admission, at 1 and 2 months after the admission did not show metaphyseal sclerosis. Laboratory values and treatment during follow-up are shown in Table 1. It is known that rapid normalization of serum calcium level and maintaining of normocalcemia are necessary to prevent acute complications and prolonged hypercalciuria and nephrocalcinosis [6]. Relative potency of alendronate to inhibit bone resorption is 10–20 times higher than that of pamidronate [7]. Although pamidronate has been used in children with vitamin D intoxication [2, 4], studies examining the efficacy of oral alendronate in children are limited. In literature, we found one case report which represented efficacy of alendronate in hypervitaminosis D [1]. There is currently little information to guide clinicians as to duration of treatment and what criteria should be used to indicate termination of the treatment. In our study normalization of serum calcium level also took almost two weeks and hypercalcemia did not recur. Another condition is duration of treatment effect. It is currently unclear how long the effect of bisphosphonate treatment will last once discontinued. When administered, bisphosphonates are cleared rapidly from the circulation. Its half-life in serum is short, a few hours or less, whereas the half-life in the bone Z. Orbak . H. Doneray . F. Keskin . A. Turgut . H. Alp . C. Karakelleoglu Department of Pediatric Endocrinology, Ataturk University Faculty of Medicine, Erzurum, Turkey