VI-DOM-A
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VI-DOM-A (VI-DOM-A).
Retinol binds to retinoic acid receptors (RARs) and retinoid X receptors (RXRs), modulating gene transcription involved in cell growth, differentiation, and immune function.
| Metabolism | Hepatic metabolism via oxidation to retinal and retinoic acid; also glucuronidation. |
| Excretion | Vitamin A is primarily excreted via bile and feces as metabolites. Renal excretion accounts for less than 5% of an oral dose. Unchanged vitamin A is not significantly excreted in urine. |
| Half-life | The terminal elimination half-life of vitamin A is 10-12 hours for retinol, but due to hepatic storage and enterohepatic recirculation, the overall body half-life can extend to 2-3 weeks with chronic dosing. |
| Protein binding | Retinol is bound to retinol-binding protein (RBP) and transthyretin in the plasma. Greater than 95% bound, with free retinol less than 5%. In hypervitaminosis, binding capacity may be exceeded, increasing free retinol. |
| Volume of Distribution | Vd is approximately 0.5-0.8 L/kg, reflecting distribution to extravascular tissues including the liver (storage), retina, and skin. The apparent Vd increases in hypervitaminosis due to nonspecific binding. |
| Bioavailability | Oral bioavailability is 80-90% under normal conditions, enhanced by dietary fat and bile salts. Intramuscular bioavailability is variable and generally lower due to precipitation at injection site; not a preferred route. |
| Onset of Action | Oral: Therapeutic effects on night blindness may be seen within 24-48 hours; peak serum retinol levels at 4-6 hours. Intramuscular: Onset 1-2 hours, but not recommended due to erratic absorption. |
| Duration of Action | Duration of clinical effect after a single oral dose is approximately 1-2 days for acute deficiency symptoms, but hepatic stores can maintain normal levels for weeks to months depending on baseline status. |
| Molecular Weight | 300.44 |
1 mL intramuscular injection once weekly; each mL contains 100,000 IU vitamin A (as retinyl palmitate) and 50,000 IU vitamin D (as ergocalciferol).
| Dosage form | CAPSULE |
| Renal impairment | No specific dose adjustment recommended; use with caution in severe renal impairment due to potential accumulation of vitamin A. |
| Liver impairment | No specific adjustment based on Child-Pugh score; avoid in severe hepatic impairment due to risk of hepatotoxicity. |
| Pediatric use | Children: 0.5 mL intramuscular injection once weekly; each 0.5 mL contains 50,000 IU vitamin A and 25,000 IU vitamin D; do not exceed recommended dose. |
| Geriatric use | Elderly: Same as adult dose (1 mL once weekly); monitor for signs of hypervitaminosis A and D, and consider lower starting dose if renal function is reduced. |
| 1st trimester | Contraindicated due to teratogenicity; risk of congenital malformations including CNS defects and cardiovascular anomalies. |
| 2nd trimester | Contraindicated; continued risk of teratogenicity and potential fetal harm. |
| 3rd trimester | Contraindicated; associated with fetal retinoid syndrome and neonatal complications. |
Clinical note
Comprehensive clinical and safety monograph for VI-DOM-A (VI-DOM-A).
| Placental transfer | Crosses placenta readily with evidence of dose-dependent teratogenic effects in human and animal studies. |
| Breastfeeding | Vitamin A in high doses is excreted in breast milk and may cause toxicity in the nursing infant. Avoid breastfeeding during therapy due to potential for hypervitaminosis A in the infant. |
■ FDA Black Box Warning
Not established. No FDA boxed warning.
| Serious Effects |
PregnancyHypersensitivity to retinoids or any component of the formulationBreastfeedingKnown hypervitaminosis A
| Precautions | Hypervitaminosis A (toxicity) with prolonged high doses; hepatotoxicity; pseudotumor cerebri; teratogenicity; avoid in pregnancy unless treating deficiency. |
| Food/Dietary | Avoid taking with dairy products or calcium-rich foods as they may interfere with absorption of certain minerals. Alcohol consumption may affect vitamin levels. |
| Clinical Pearls |
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| Lactation Rating |
| Avoid |
| Teratogenic Risk | VI-DOM-A is classified as FDA Pregnancy Category X. There is evidence of fetal harm in the first trimester including increased risk of central nervous system defects, cardiovascular malformations, and orofacial clefts. Use is contraindicated throughout pregnancy. Risk for all trimesters is high, with no safe window. |
| Fetal Monitoring | For women of childbearing potential: pregnancy test prior to initiation, confirm negative result, and monthly thereafter. Monitor for signs of fetal distress via ultrasound and fetal heart rate monitoring if accidental exposure occurs. In case of exposure, referral to maternal-fetal medicine specialist for detailed anatomical ultrasound and echocardiography is indicated. |
| Fertility Effects | VI-DOM-A may impair fertility in females by causing anovulation or menstrual irregularities. In males, it may reduce sperm count and motility. These effects are reversible upon discontinuation. |
| VI-DOM-A is a combination product containing vitamins and minerals. Avoid concurrent use with other multivitamins to prevent toxicity. Monitor for allergic reactions, especially in patients with hypersensitivity to any component. Use cautiously in renal impairment due to risk of aluminum toxicity. |
| Patient Advice | Take with food to minimize gastrointestinal upset. · Do not exceed recommended dose; overdose can be harmful. · Inform your doctor if you are pregnant, breastfeeding, or have kidney disease. · Store at room temperature away from moisture and heat. · Keep out of reach of children. |