CALCITRIOL

Posology The dose of calcitriol capsules should be carefully adjusted for each patient according to the biological response so as to avoid hypercalcaemia. Treatment with calcitriol must always be started with the lowest possible dose and the dosage must not be increased without careful monitoring of serum calcium (see “Monitoring the patients”).

The effectiveness of treatment depends in part on an adequate daily intake of calcium, which should be augmented by dietary changes or supplements if necessary. As calcitriol facilitates the absorption of calcium by the gastrointestinal tract, a lower calcium intake may be maintained in some patients under treatment with this medicinal product.

Patients who are susceptible to hypercalcaemia may only require low doses of calcium and no supplementation. Monitoring the patients The necessary routine diagnostic tests include determining the serum calcium, phosphorus, magnesium and alkaline phosphatase levels, and the calcium and phosphate levels in the urine in the 24-hour test.

During the stabilisation phase of the calcitriol treatment, the serum calcium must be checked at least twice a week. Once the optimum dose of calcitriol has been determined, the serum calcium need only be checked once a month (or as described below for the individual indications).

The samples for evaluating the serum calcium must be taken without using a tourniquet. Should the serum calcium levels rise to 1 mg/100ml (250 μmol/l) above normal (9 to 11 mg/100 ml or 2250 – 2750 μmol/l), or serum creatinine rises to > 120 μmol/l, treatment with calcitriol should be stopped immediately until normocalcaemia ensues.

The serum calcium and phosphate levels must be checked every day during the hypercalcaemia period. To facilitate rapid normalisation of the serum calcium levels, the calcium supplement, used in the treatment of renal osteodystrophy, hypoparathyroidism and rickets, may even be stopped.

25 mcg lower than the previous dose. The quantity of calcium taken in the daily diet must be estimated and, if indicated, the intake must be adjusted. Adults Renal Osteodystrophy (patients on haemodialysis) The efficacy of the treatment is dependent on the simultaneous intake of calcium: adult patients must be given a calcium supplement of 600 1000 mg per day.

25 mcg of calcitriol. 25 mcg every other day are sufficient. 25 mcg at 2 - 4 week intervals. During this period, serum calcium levels should be determined at least twice weekly. 0 mcg. If hypercalcaemia is detected, the administration of calcitriol and the calcium supplement should be stopped immediately until the serum calcium normalizes.

The adverse reactions listed below reflect the experience from investigational studies of calcitriol, and the post-marketing experience. The most commonly reported adverse reaction was hypercalcaemia. The ADRs listed in the table below are presented by system organ class and frequency categories, defined using the following convention: very common (≥1/10); common (≥1/100 to <1/10); uncommon (≥1/1,000 to <1/100); rare (≥1/10,000 to <1/1,000); very rare (<1/10,000); not known (cannot be estimated from the available data).

Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness. e. 4). Occasional acute symptoms include decreased appetite, headache, nausea, vomiting, abdominal pain or abdominal pain upper and constipation.

e. much faster than in treatment with vitamin D3 preparations. Chronic effects may include muscular weakness, weight decreased, sensory disturbances, pyrexia, thirst, polydipsia, polyuria, dehydration, apathy, growth retardation and urinary tract infections.

For signs and symptoms of acute or chronic calcitriol intoxication, see section

There is a close correlation between treatment with calcitriol and the development of hypercalcemia. All other vitamin D compounds and their derivative, including proprietary compounds or foodstuffs which may be “fortified” with vitamin D, should be withheld during treatment with calcitriol.

g. increased consumption of dairy products) or uncontrolled intake of calcium preparations may trigger hypercalcaemia. Patients and their families should be advised that strict adherence to the prescribed diet is mandatory and they should be instructed on how to recognise the symptoms of hypercalcaemia.

2). g. those who have undergone surgery, are particularly exposed to the risk of hypercalcemia. Calcitriol increases inorganic phosphate levels in serum. While this is desirable in patients with hypophosphatemia, caution is called for in patients with renal failure because of the danger of ectopic calcification.

62 mmol/l) by the oral administration of appropriate phosphate binding agents and low phosphate diet. The serum calcium times phosphate (Ca x P) product should not be allowed to exceed 70 mg2/dl2. Patients with vitamin D-resistant rickets (familial hypophosphatemia) who are being treated with calcitriol must continue their oral phosphate therapy.

However, possible stimulation of intestinal absorption of phosphate by calcitriol should be taken into account since this effect may modify the need for phosphate supplementation. Since calcitriol is the most effective vitamin D metabolite available, no other vitamin D preparation should be prescribed during treatment with calcitriol, thereby ensuring that the development of hypervitaminosis D is avoided.

g. 5). Patients with normal renal function who are taking calcitriol should avoid dehydration. Adequate fluid intake should be maintained. In patients with normal renal function, chronic hypercalcemia may be associated with an increase in serum creatinine.

1 • If there is evidence of vitamin D toxicity