VECTICAL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VECTICAL (VECTICAL).
VECTICAL (calcitriol) is a vitamin D analog that binds to vitamin D receptors (VDRs) in target tissues, increasing intestinal calcium absorption, renal calcium reabsorption, and enhancing osteoclast activity to mobilize calcium from bone, thereby raising serum calcium levels.
| Metabolism | Primarily metabolized by CYP24A1 (mitochondrial 24-hydroxylase) and CYP3A4 (minor pathway) to inactive metabolites such as calcitroic acid and 1,24,25-trihydroxyvitamin D3. |
| Excretion | Primarily hepatobiliary (74%) and fecal (14%), with renal excretion accounting for <1% of the administered dose as unchanged drug. Enterohepatic recirculation occurs. |
| Half-life | Mean terminal elimination half-life is approximately 3.7 hours (range 2.5–5.5 hours) in healthy adults. Clinically, steady-state is achieved within 2–3 days. |
| Protein binding | Approximately 99.9% bound to vitamin D-binding protein (DBP; GC-globulin) and albumin. |
| Volume of Distribution | Volume of distribution is estimated at 0.6–1.0 L/kg, indicating distribution into tissues including adipose and bone. |
| Bioavailability | Not applicable for systemic administration; topical formulation has minimal systemic absorption (approximately 1–5% of applied dose). |
| Onset of Action | Onset of action for topical VECTICAL (calcitriol ointment) is typically within 1–2 weeks of daily application for plaque psoriasis. |
| Duration of Action | Duration of therapeutic effect is variable; maximal improvement is often seen after 8 weeks of treatment. Lesions may recur after discontinuation. |
1-2 mcg orally twice daily, increased every 2-4 weeks based on serum calcium and PTH levels. Maximum dose: 4 mcg twice daily.
| Dosage form | OINTMENT |
| Renal impairment | No specific GFR-based adjustments recommended; monitor serum calcium and phosphate closely in moderate to severe renal impairment. |
| Liver impairment | No specific Child-Pugh based adjustments; use with caution in severe hepatic impairment. |
| Pediatric use | Not established for patients <18 years of age. |
| Geriatric use | No specific dose adjustment; monitor serum calcium and PTH levels closely due to age-related renal function decline. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for VECTICAL (VECTICAL).
| Breastfeeding | Calcitriol is present in human milk at levels similar to maternal serum; M/P ratio is approximately 0.5. No adverse effects reported in breastfed infants with maternal use of physiological doses. However, avoid high doses due to potential for infant hypercalcemia. Monitor infant for signs of hypercalcemia (e.g., vomiting, constipation, hypotonia). |
| Teratogenic Risk | FDA Pregnancy Category C. In animal studies, hypercalcemia from calcitriol (active ingredient) caused skeletal abnormalities, reduced fetal weight, and increased fetal mortality. Human data are limited. First trimester: potential for teratogenicity if maternal hypercalcemia occurs. Second and third trimesters: risk of fetal hypercalcemia, suppression of parathyroid function, and nephrocalcinosis; avoid use unless clearly needed and only if maternal calcium levels are maintained within normal range. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypercalcemia or evidence of vitamin D toxicity","Hypersensitivity to calcitriol or any formulation component","Patients with known hypercalciuria or calcium-containing renal calculi"]
| Precautions | ["Hypercalcemia: Monitor serum calcium and phosphate levels regularly; risk of cardiac arrhythmias and seizures","Adynamic bone disease: Prolonged suppression of PTH may lead to low bone turnover","Digitalis toxicity: Hypercalcemia increases sensitivity, monitor digoxin levels","Aluminum hydroxide: Avoid concurrent use with phosphate binders; may cause hypermagnesemia","Renal osteodystrophy: Use with caution in patients with bone metastases or hypercalcemic disorders"] |
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| Fetal Monitoring | Maternal: Serum calcium, phosphate, magnesium, and creatinine at baseline and periodically (e.g., weekly) during dose titration; monitor for hypercalcemia (e.g., nausea, vomiting, weakness). Fetal/neonatal: Consider ultrasonography for signs of nephrocalcinosis or skeletal abnormalities if prolonged high-dose use; assess infant for hypercalcemia and parathyroid suppression postpartum. |
| Fertility Effects | No specific fertility studies in humans. In rats, high doses of calcitriol caused reduced fertility in females. Relevance to humans is unknown but may be associated with alterations in calcium homeostasis affecting ovulation or implantation. |