selenious acid (Rx)

Frequency Not Defined

Pulmonary embolism due to pulmonary vascular precipitates

Vein damage and thrombosis

Aluminum toxicity

Contraindications

None

Cautions

Pulmonary vascular precipitates causing pulmonary vascular emboli and pulmonary distress reported in patients receiving PN; in some fatal cases, pulmonary emboli occurred as a result of calcium phosphate precipitates; if signs of pulmonary distress occur, stop infusion and initiate medical evaluation

Monitor selenium concentrations, fluid and electrolyte status, serum osmolarity, blood glucose, liver and kidney function, blood cell count, and coagulation parameters during treatment

Vein damage and thrombosis

• Selenious acid has a low pH and must be prepared and used as an admixture in PN solutions; it is not for direct IV infusion
• Additionally, consider final PN solution osmolarity to determine peripheral versus central administration
• Solution with osmolarity of >900 mOsm/L must be infused through a central catheter
• Infusion of hypertonic nutrient injections into a peripheral vein may result in vein irritation, vein damage, and/or thrombosis

Aluminum toxicity

• Selenious acid injection contains aluminum that may be toxic
• Aluminum may reach toxic levels with prolonged parenteral administration if kidney function is impaired
• Preterm infants are particularly at risk for aluminum toxicity because of immature kidneys, and they require large amounts of calcium and phosphate solutions, which also contain aluminum
• Patients with impaired kidney function, including preterm neonates, who receive >4-5 mcg/kg/day of parenteral aluminum can accumulate aluminum to levels associated with central nervous system and bone toxicity
• Tissue loading may occur at even lower rates of administration
• Exposure to aluminum from selenious acid <0.6 mcg/kg/day
• Determine total daily exposure to aluminum from entire admixture contents; daily aluminum should not exceed 5 mcg/kg/day

Drug interaction overview

• Selenium is a polyvalent cation that may interfere with absorption of certain drugs (eg, baloxavir marboxil, bictegravir, bisphosphonates, eltrombopag, penicillamine)

Pregnancy

Administration of the recommended dose in PN is not expected to cause major birth defects, miscarriage, or adverse maternal or fetal outcomes

Animal reproduction studies have not been conducted

Clinical considerations

• Deficiency of trace elements, including selenium, is associated with adverse pregnancy and fetal outcomes
• Pregnant women have an increased metabolic demand for trace elements, including selenium
• PN with selenium should be considered if a pregnant woman’s nutritional requirements cannot be fulfilled by oral or enteral intake

Lactation

Selenium is present in human milk; administration of the approved recommended dose is not expected to cause harm to a breastfed infant

There is no information on the effects of selenious acid on milk production

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Selenious acid is converted in vivo to hydrogen selenide via glutathione-involved electron reductions

Hydrogen selenide acts as a selenium pool to form selenoproteins, which include, but are not limited to, glutathione peroxidase, iodothyronine deiodinase, peroxidase, and thioredoxins

Distribution

Protein bound: 85% (within 4-6 hr); 95% (within 24 hr)

Metabolism

Converted in vivo to hydrogen selenide via glutathione-involved electron reductions

Elimination

Excretion: Primarily eliminated in urine

IV Preparation

Prepare per current standard of practice as an admixture for PN solutions

IV Administration

Not for direct IV infusion; must be prepared and used as an admixture in PN solutions

PN solutions with osmolarity ≥900 mOsm/L must be infused through a central venous catheter

Inspect final PN solution to ensure that precipitates have not formed during mixing or addition of additives

Discard if any precipitates are observed

Storage

Unopened vials: Store at 20-25ºC (68-77ºF)