Myalfa

Uses

Myalfa is used for:

• It is used to increase the amount of vitamin D in your body. This often increases calcium levels as well which can help in treatment of certain illnesses.
• In general this drug is used to treat diseases where the amount of calcium and phosphate (which is controlled by the level of vitamin D) in your body needs changing.
• Benefits of being on this drug can include control of the levels of calcium and phosphate in your body.
• Treat and prevent bone conditions that are caused by kidney failure (osteodystrophy)
• Treat illnesses and abnormalities affecting the parathyroid glands which make a substance called the parathyroid hormone.
• Correct low levels of calcium in the blood of newborn babies (hypocalcaemia)
• Treat the softening and deformity of the bones due to lack of calcium (rickets or osteomalacia)

Myalfa is also used to associated treatment for these conditions: Hypocalcemia, Hypophosphatemic Rickets, Hypovitaminosis D, Nutritional Rickets, Osteodystrophy, Osteomalacia, Secondary Hyperparathyroidism (SHPT), Hypophosphatemic osteomalacia

How Myalfa works

In conditions like chronic renal failure, renal bone disease, hypoparathyroidism, and vitamin D dependent rickets, the kidneys' capacity for 1α-hydroxylation is impaired, leading to reduced production of endogenous 1,25-dihydroxyvitamin D and aberrated mineral metabolism. As an active and potent analog of vitamin D, alfacalcidol works to restore the functions and activities of endogenous 1,25-dihydroxyvitamin D.

Dosage

Myalfa dosage

Adults: The usual starting dose is 1 microgram each day. People usually take between 1 and 3 micrograms each day. Most people take between 0.25 and 1 microgram each day once the blood test results show the medicine is working.

If you have very low levels of calcium in your blood, your doctor may prescribe between 3 and 5 microgram each day. Your doctor may prescribe another medicine called a calcium supplement to take as well as Myalfa. This will help to keep the right amount of calcium level in your blood.

Elderly: The usual starting dose is 0.5 microgram each day.

Children:

• Newborn and premature babies: The usual starting dose is 0.05 to 0.1 microgram per kilogram of body weight each day. If the level of calcium in their blood is very low, up to 2 micrograms per kilogram of body weight may be needed each day. A dose of 0.1 microgram per kilogram body weight each day is used to stop low blood calcium levels in premature babies.
• Children weighing less than 20 kilograms: The usual starting dose is 0.05 microgram per kilogram body weight each day.
• Children weighing more than 20 kilograms: The usual starting dose is 1 microgram each day.

Side Effects

Anorexia, nausea, vomiting, diarrhoea, lassitude, polyuria, sweating, headache, thirst, vertigo, pruritus, rash, urticaria. Hypercalcaemia, hypercalciuria and ectopic calcification.

In case of renal impairment, hyperphosphataemia. In hypercalcaemic dialysis patients, possibility of calcium influx from the dialysate should be considered.

Toxicity

There is a discrepancy across a number of reported LD₅₀ values for alfacalcidol, which can be attributed to differences in the procedures used in laboratories. Oral LD₅₀ in mice ranges from 440 to 490 mcg/kg. Intravenous in mice was 290 mcg/kg; however, another source presented 56 mcg/kg in female mice and 71 mcg/kg in male mice. Oral LD₅₀ in rats ranges from 340 to 720 mcg/kg.

In case of an acute accidental overdose following oral administration, emesis or gastric lavage can be induced to prevent further drug absorption. Mineral oil may be used to promote fecal drug elimination in instances where the drug was already absorbed in the stomach.

Myalfa overdose can lead to hypercalcemia, hypercalciuria, and hyperphosphatemia. Similarly, a high intake of calcium and phosphate concurrently with a therapeutic dose of alfacalcidol can result in those conditions. Hypercalcemia most commonly presents with headache, weakness, hypertension, somnolence, dizziness, sweating, anorexia, nausea, vomiting, diarrhea, constipation, polyuria, polydipsia and muscle and bone pain, and metallic taste. Hypercalcemia should be responded to with discontinuation of alfacalcidol, a low calcium diet and withdrawal of calcium supplements. Prolonged hypercalcemia can lead to nephrocalcinosis, nephrolithiasis, and reduced kidney function. In cases of severe hypercalcemia, general supportive measures are recommended, which may include forced diuresis and close monitoring of renal function, electrolytes, and electrocardiographs. Monitoring for abnormalities is especially critical in patients receiving digitalis glycosides. Management with glucocorticosteroids, loop diuretics, bisphosphonates, and calcitonin, as well as hemodialysis with low calcium content, may be considered.

Precaution

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

Interaction

Thiazides may increase the risk of hypercalcaemia. Some antiepileptics e.g. carbamazepine, phenobarbital, phenytoin and primidone may increase vitamin D requirements. Rifampicin, isoniazid and corticosteroids may reduce the efficacy of vitamin D.

Food Interaction

• Take with or without food. Food does not affect the bioavailability.

Elimination Route

Myalfa is absorbed passively and almost completely in the small intestine.

Half Life

The half-life of alfacalcidol ranges from three to four hours.

Pregnancy & Breastfeeding use

FDA has not yet classified the drug into a specified pregnancy category.

Contraindication

Hypercalcaemia, metastatic calcification, hyperphosphataemia (except when occurring with hypoparathyroidism), hypermagnesaemia.

Innovators Monograph

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