Mechanism of Action

Although alfacalcidol is widely used in the treatment of osteoporosis, its mechanism of action in bone has not been fully understood. Alfacalcidol stimulates intestinal calcium (CA) absorption, increases urinary CA excretion and serum CA levels, and suppresses parathyroid hormone (PTH) secretion.

Pharmacokinetic Properties:

Alfacalcidol is a precursor of active calcitriol. It does not require renal hydroxylation but requires 25-hydroxylation in the liver for conversion to calcitriol.

• Absorption: Adequately absorbed from the GI tract (oral).

• Delivery: Fat and muscle tissue; Enters into breast milk. Protein-binding: specific for α-globulin.

• Metabolism: Hepatic; Rapidly converted to calcitriol.

• Excretion: Stool and urine (small amounts)

Drug-Drug interactions:

Thiazide may increase the risk of hypercalcemia. Certain antiepileptics such as carbamazepine, phenobarbital, phenytoin, primidone may increase the need for vitamin D. Rhimpsin, INH and corticosteroids may reduce the efficacy of vitamin D.

Precautions:

Inform the physician if the patient is allergic to the active ingredients and any other drugs. Brief about the allergy and the signs like:

• Rash

• Itching

• Shortness of breath

• Swelling of face, lips, tongue or throat or any other signs.

The patient should tell the doctor about any history of renal impairment.

Pregnancy, lactation, renal impairment, infants, elderly. Monitor serum levels of calcium in patients with renal failure. Caution in hypercalciuria esp in those with a history of renal calculi. Avoid in patients with hypersensitivity to injections containing propylene glycol.

Breastfeeding:

Calcium is found in breast milk. When calcium carbonate is used at recommended doses, it is unlikely to be harmful to the nursing child.

Fertility:

When men take calcium carbonate, there have been no studies looking at male fertility in pregnancy or potential problems for pregnancy.

Dosage:

Adults- Initially, 1 mcg daily. Maintenance: 0.25–1 mcg daily. Adults- Initially, 1 mcg daily. Maintenance: 0.25-1 mcg daily. Overall- Initially, 1 mcg daily. Maintenance: 0.25–1 mcg daily.

Child – Premature infant and newborn: 0.05–0.1 mcg / kg daily; <20 kg: 0.05 mcg / kg daily.

Elderly – 0.5 mcg per day.

Duration of action:

Up to 2 week

Adverse Reaction:

Get emergency medical attention if you have signs of an allergic reaction: urticaria; Shortness of breath; swelling of your face, lips, tongue, or throat.

Storage:

Store below 25°C.

Overdosage:

If anyone has treatment and has severe symptoms such as passing out or trouble in breathing, talk to the doctor. Symptoms of an overdose may include nausea/vomiting, loss of appetite, mental/mood changes, headache, weakness, dizziness.

Contraindications:

Hypercalcemia, Metastatic Calcification, Hyperphosphataemia (except when occurring with hypoparathyroidism), Hypermagnesaemia

Side effects:

Anorexia, Nausea, Vomiting, Diarrhoea, Lassitude, Polyuria, Sweating, Headache, Thirst, Vertigo, Pruritus, Rash, Urticaria, Hypercalcaemia, Hypercalciuria and ectopic calcification, Hyperphosphataemia.

Warnings:

Follow all instructions on your medicine label and package. Tell each of your healthcare providers about all of your medical conditions, allergies, and all the medicines you use.

Pregnancy:

Normal daily intake of calcium carbonate appears to be safe and effective to use during pregnancy. During pregnancy, the use of calcium carbonate above the recommended dietary allowances should be avoided.

During lactation, please consult a physician.