Composition | Calcitriol-0.25mg, Calcium Carbonate-500mg, Methylcobalamin-1500mcg, Vitamin B6-3mg, Folic Acid-1.5mg |
Indication | Renal osteodystrophy Postmenopausal osteoporosis Hypocalcaemia Mild to moderate plaque psoriasis |
Mechanism of Action | Calcitriol promotes Ca absorption in the intestines and retention at the kidneys thus increasing serum Ca levels. It also increases renal tubule phosphate resorption, consequently decreasing serum phosphatase levels, PTH levels and bone resorption. |
Pharmacokinetic's | Absorption: Rapidly absorbed from the intestines. Mean absorption for topical admin: Approx 10%. Time to peak plasma concentration: W/in 2-6 hr (oral). Distribution: Bound to a specific vit D binding protein (DBP) and to lipoproteins and albumin to a lesser extent. Plasma protein binding: 99.9%. Metabolism:Hydroxylated and oxidised in the kidney and in the liver by CYP24A1 isoenzyme. Excretion: Mainly excreted in the bile and faeces. Elimination half-life: 5-8 hr. |
Side effects | Weakness headache nausea vomiting |
Drug drug interaction | - |
Precaution | Patient w/ malabsorption syndrome. Renal or hepatic impairment. Pregnancy and lactation. Patient Counselling Maintain adequate fluid intake. Avoid uncontrolled intake of additional Ca-containing preparations. Monitoring Parameters Periodically monitor serum Ca, Mg, phosphorus and alkaline phosphatase and 24-hr urinary Ca and phosphorus. During initial phase, determine serum Ca and phosphorus at least twice wkly. |
Dosage | Adult: PO Renal osteodystrophy Initial: 0.25 mcg/day. Patient w/ normal or slightly reduced Ca levels: 0.25 mcg every other day. If no response w/in 2-4 wk, increase daily dose by 0.25 mcg at 2-4 wk intervals. Postmenopausal osteoporosis 0.25 mcg bid. IV Hypocalcaemia For patients undergoing chronic renal dialysis: 1 mcg (0.02 mcg/kg) to 2 mcg 3 times wkly, approx every other day. If no satisfactory response observed, increase by 0.5-1 mcg at 2-4 wk intervals. Topical Mild to moderate plaque psoriasis As 3 mcg/g oint: Apply to affected areas bid. Max: 30 g/day. Max duration: 6 wk. |