| Alfacalcidol Pharmacology |
| Alfacalcidol |
| About Alfacalcidol |
| Nutritional supplement,Vitamin D derivative, Antihypoparathyroid, Antihypocalcemic. |
| Mechanism of Action of Alfacalcidol |
| Alfacalcidol is a prodrug of Vitamin D and is rapidly hydroxylated in the liver in to calcitriol. Vitamin D exerts it`s action by influencing calcium homoeostasis. It increases the intestinal absorption of calcium and phosphate. It binds to the cytoplasmic Vitamin D receptor and translocates to the nucleus and thus increases the synthesis of specific m RNA and regulates protein synthesis. It increases the synthesis of a carrier protein for calcium called “calbindin” or calcium binding protein. Activation of Vitamin D receptor enhances endocytotic capture of calcium and it`s transport across duodenal mucosal cells in a vesicular form. Vitamin D promotes resorption of calcium and phosphate from bone by enhancing recruitment and differentiation of osteoclast precursors in the bone remodeling units. It helps in bone mineralization. |
| Pharmacokinets of Alfacalcidol |
| Absorption: Well absorbed orally, Distribution: Widely distributed in a protein bound form. It is stored in adipose tissue and liver. Metabolism: It is hydroxylated in to calcitriol in liver. Excretion: Excreted mainly through bile. |
| Onset of Action for Alfacalcidol |
| N/A |
| Duration of Action for Alfacalcidol |
| N/A |
| Half Life of Alfacalcidol |
| N/A |
| Side Effects of Alfacalcidol |
| 1.Hypercalcaemia 2.Fatigue 3.Weakness 4.Diarrhoea 5.Vomiting 6.Sluggishness 7.Albuminuria 8.Polyuria 9.Calcification of soft tissues (blood vessels, parenchymal organs including heart) 10.Renal stones 11.Growh retardation in children 12.Hypertension 13.Anorexia 14.Nausea 15.Constipation 16.Hyperphosphataemia. |
| Contra-indications of Alfacalcidol |
| 1.Hypercalcaemia 2.Hypervitaminosis D 3.Hyperphosphataemia (except when occurring with hypoparathyroidism 4.Hypermagnesaemia. |
| Special Precautions while taking Alfacalcidol |
| 1 Renal impairment 2.Hypercalciurea 3.Renal stones 4.Coronary diseases. |
| Pregnancy Related Information |
| Use with caution |
| Old Age Related Information |
| Use with caution |
| Breast Feeding Related Information |
| Use with caution |
| Children Related Information |
| Use with caution |
| Indications for Alfacalcidol |
| 1.Rickets and Osteomalacia 2.Hypoparathyroidism with bone disease 3.Renal osteodystrophy 4.Osteoporosis |
| Interactions for Alfacalcidol |
| Digitallis preparations: Cardiac arrhythmias precipitated. Thiazide Diuretics: Hypercalcaemic response enhanced. Barbiturates & other enzyme inducing anticonvulsants: Reduce efficacy. Minteral Oil: Prolonged use reduces efficacy. Cholestyramine, Cholestipol, Sucralfate, Aluminium based Antacids: Reduced efficacy by decreasing absorption of alfacalcidol. Magnesium based Antacids or Laxatives: Hypermagnesaemia in those on chronic renal dialysis. |
| Typical Dosage for Alfacalcidol |
| Oral: Starts with 1mcg daily. Adjusted based on patients response to 2mcg daily if required. Children over 20kg: Starts with 1mcg daily. Adjusted based on patient`s response. Children under 20kg: 0.5mcg daily or 0.05mcg/kg/day |
| Schedule of Alfacalcidol |
| C1 |
| Storage Requirements for Alfacalcidol |
| Store in a well closed container in a cool place. Protect from light and excess heat. Keep out of reach of children. |
| Effects of Missed Dosage of Alfacalcidol |
| Take the missed dose as soon as noticed and if it is the time for next dose then skip the missed dose. Continue the regular schedule. Do not double the dose. |
| Effects of Overdose of Alfacalcidol |
| Provide supportive and symptomatic treatment. Stops the treatment and starting a low calcium diet. Increases the fluid intake and administer Loop diuretics like furosemide may be given with saline I.V. infusion to increase calcium excretion. Calcitonin may decrease hypercalcaemia. |
Monday, December 23, 2024
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