| drug name | Calcitriol (1,25-dihydroxyvitamin D) |
| classification | Vitamin D Analogue; Calcium Homeostasis Regulator |
| pharmacokinetics | Calcitriol is a highly potent form of vitamin D, rapidly absorbed in the gut. It is primarily metabolized in the liver and kidneys. Peak serum concentrations are generally reached within 2-4 hours after oral administration. The elimination half-life is variable depending on the dose, and can range from 3 to 6 hours. The primary route of elimination is via metabolism in the liver and kidney, followed by excretion in the bile and urine. |
| suggested dosage | Dosage varies greatly depending on the indication. It's crucial to consult with a physician. A typical starting dose for certain conditions (e.g., hypocalcemia, secondary hyperparathyroidism) might be in the range of 0.25-2 mcg daily or as directed by the prescribing physician, tailored to individual patient needs. |
| indications | | 1 | Hypocalcemia (low blood calcium levels) | | 2 | Secondary hyperparathyroidism (a condition where the parathyroid glands produce too much parathyroid hormone, often due to kidney disease) | | 3 | Rickets and osteomalacia (bone softening conditions) | | 4 | Treatment of Vitamin D Deficiency | | 5 | Certain types of bone disease |
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| safety in pregnancy | Limited data exists on the safety of calcitriol during pregnancy. While vitamin D deficiency is known to be problematic during pregnancy, doses should be carefully considered, guided by a physician. Consult with a physician regarding the potential benefits and risks. |
| safety in breastfeeding | Calcitriol is considered generally compatible with breastfeeding. However, as with all medications, it's advisable to consult with a healthcare professional to determine the optimal dosage and potential risks. |
| side effects | | 1 | Nausea, vomiting | | 2 | Headache | | 3 | Constipation | | 4 | Anorexia | | 5 | Polyuria (excessive urination) | | 6 | Increased thirst | | 7 | Weakness | | 8 | Elevated blood calcium levels (hypercalcemia). This is a serious concern and requires close monitoring and dose adjustments. Other symptoms of hypercalcemia may include: abdominal pain, fatigue, depression, confusion, thirst, frequent urination, kidney stones, and cardiac arrhythmias. Regular monitoring of blood calcium levels is crucial. | | 9 | Kidney stones | | 10 | Elevated blood phosphorus |
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| alternatives | |
| contraindications | | 1 | Hypercalcemia (high blood calcium levels) | | 2 | Significant kidney impairment | | 3 | Hypersensitivity to Vitamin D analogs | | 4 | Active sarcoidosis or other granulomatous diseases. |
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| interactions | | 1 | Thiazide diuretics (may increase blood calcium levels) | | 2 | Certain medications for osteoporosis (e.g., bisphosphonates) | | 3 | Digitalis glycosides (may increase risk of cardiac arrhythmias) | | 4 | Antacids, laxatives (may interfere with absorption of calcitriol) | | 5 | Certain medications for HIV (e.g., ritonavir) | | 6 | Other calcium containing supplements |
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| warnings and precautions | Regular monitoring of blood calcium, phosphorus, and kidney function is essential, especially during prolonged therapy. Patients with underlying kidney disease may require more frequent monitoring. Monitor for signs of hypercalcemia (see side effects). |
| additional information | Calcitriol is a potent medication. It should only be used as prescribed by a healthcare professional. The specific dosage will be individualized for each patient based on medical history and condition. |
| patient specific notes | Age and weight are factors to be considered but are not the primary determinants for dosage. The patient's specific underlying health conditions and lab values (e.g. blood calcium, kidney function) are much more significant and will influence appropriate dosage and monitoring. Always consult a healthcare professional for medical advice. |
| patient age | 25 |
| patient weight | 70 |
