Calcitriol

Registered South African indications:

• Post-menopausal osteoporosis
• Renal bone disease (renal osteodystrophy)
• Rickets and osteomalacia
• Hypoparathyroidism
• Pseudo-hypoparathyroidism

Contraindications

• Hypersensitivity to the active ingredient or any of its excipients
• Diseases associated with hypercalcaemia
• Metastatic calcification
• Vitamin D toxicity

Cautions

• Pregnancy
• Breastfeeding
• Renal impairment
• Diet
• Immobilised patients
• Vitamin D-resistant rickets (familial hypophosphataemia) 
• Switching from a long acting vitamin D preparation (e.g. ergocalciferol (vitamin D) or colecalciferol) to calcitriol
• Dehydration
• Fructose intolerance 

Forms avail. in SA and covered in this monograph: cap

Treatment of post-menopausal osteoporosis

• Oral (cap): Initial: 0.25μg, 12hrly

Renal bone disease

Continuous therapy

• Oral (cap): Initial: 0.25μg, dly; Titrate by 0.25μg at intervals of 2-4 weeks; Usual maintenance dose: 0.5-1.0μg, dly

Pulse therapy

• Oral (cap): 0.1μg/kg/week, in 2-3 divided doses throughout the week at the end of dialysis; Max: 12μg/week

Secondary hyperparathyroidism associated with chronic kidney disease

• Oral (cap): 0.25-4.0μg, dly

Hypophosphataemic vitamin D-resistant rickets and osteomalacia
Nutritional and malabsorptive rickets and osteomalacia

• Oral (cap): Initial: 0.25μg, dly; Titrate by 0.25μg at intervals of 2-4 weeks

Pseudo-vitamin D-deficiency rickets and osteomalacia

• Oral (cap): Initial: 0.5μg, 12hrly; Titrate according to serum calcium and parathyroid hormone levels; Usual maintenance dose: 0.25μg, dly

Pseudo-hypoparathyroidism

• Oral (cap): Initial: 0.25μg, dly; Titrate at intervals of 2-4 weeks; Usual maintenance dose: 0.5-2μg, dly

A prerequisite for optimal efficacy of calcitriol is adequate but not excessive calcium intake at the beginning of therapy; Total daily calcium intake should average 800mg and should not exceed 1000mg

Paed. forms avail. in SA and covered in this monograph: cap

Hypocalcaemia in hypoparathyroidism
Hypocalcaemia in pseudohypoparathyroidism

• Oral (cap): 0.01-0.04μg/kg, dly

Pregnancy

• Caution
• The safety of calcitriol during pregnancy has not been established. Supravalvular aortic stenosis has been produced in foetuses by near-fatal oral doses of vitamin D in pregnant rabbits. There is no evidence to suggest that vitamin D is teratogenic in humans even at very high doses. Calcitriol should be used during pregnancy only if the benefits outweigh the potential risk to the foetus

Breastfeeding

• Caution
• It should be assumed that exogenous calcitriol passes into breast milk. In view of the potential for hypercalcaemia in the mother and for adverse reactions from calcitriol in nursing infants, mothers may breastfeed while taking calcitriol, provided that the serum calcium levels of the mother and infant are monitored

Renal Impairment

• Caution; no dose adjustment recommended

Hepatic Impairment

• No dose adjustment recommended

Elderly

• No dose adjustment recommended

Porphyria Information

• Probably not porphyrinogenic (PNP)

Drugs in Sport

• Permitted - No warnings

Central Nervous System Disorders

• Apathy
• Psychiatric disturbances
• Headache
• Muscular weakness
• Sensory disturbance
• Somnolence

Cardiovascular Disorders

• Cardiac arrhythmias

Gastrointestinal Disorders

• Abdominal pain
• Nausea and vomiting
• Constipation
• Paralytic ileus

Genitourinary Disorders

• Urinary tract infection
• Polyuria
• Nocturia

Endocrine and Metabolic Disorders

• Hypercalcaemia
• Decreased appetite
• Polydipsia
• Dehydration
• Decreased weight
• Increased blood creatinine

Musculoskeletal Disorders

• Growth retardation

Skin and Subcutaneous Tissue Disorders

• Rash
• Erythema
• Pruritus

Immune, Blood and Lymphatic System Disorders

• Hypersensitivity  
• Urticaria
• Fever

Others

• Calcinosis
• Thirst

• Calcium-containing agents
• Thiazide diuretics
• Digitalis
• Corticosteroids
• Magnesium-containing agents
• Phosphate-binding agents
• Bile acid sequestrants
• Cholestyramine
• Sevelamer

• Serum calcium

Specific cases may require

• Urine calcium
• Serum phosphorus
• Serum magnesium
• Alkaline phosphate
• Renal function

Calcitriol is the most active known form of vitamin D in stimulating intestinal calcium transport. It is normally formed in the kidneys from its immediate precursor, 25-hydroxycholecalciferol. In physiological amounts it augments the intestinal absorption of calcium and phosphate and plays a significant part in the regulation of bone mineralisation. 

Capsule 0.25μg

• Rocaltrol (Roche) originator