Selenium Supplements (Systemic)

This monograph includes information on the following:

1) Selenious Acid 
2) Selenium

VA CLASSIFICATION
Primary: TN499

Commonly used brand name(s): Sele-Pak1; Selepen1.

Note: For a listing of dosage forms and brand names by country availability, see Dosage Forms section(s).

Not commercially available in Canada.



Category:


Nutritional supplement (mineral)—

Indications

Accepted

Selenium deficiency (prophylaxis and treatment)—Selenium supplements are indicated in the prevention and treatment of selenium deficiency, which may result from inadequate nutrition or intestinal malabsorption, but does not occur in healthy individuals receiving an adequate balanced diet. {19} For prophylaxis of selenium deficiency, dietary improvement, rather than supplementation, is advisable. For treatment of selenium deficiency, supplementation is preferred. {32}
—Deficiency of selenium may lead to lightening in color of the fingernail beds, {02} {03} {07} muscle discomfort or {06} {07} {08} weakness, and cardiomyopathy. {02} {04} {05}
—Clinical deficiencies of selenium in the U.S. are rare. Selenium supplements may be necessary in Keshan disease, a form of selenium deficiency that has been reported in areas of the world in which the soil is poor in selenium. {18} {20}
—Some unusual diets (e.g., reducing diets that drastically restrict food selection) may not supply minimum daily requirements of selenium. Supplementation may be necessary in patients receiving total parenteral nutrition (TPN) {04} {05} {06} {07} {08} or undergoing rapid weight loss or in those with malnutrition, because of inadequate dietary intake.
—Recommended intakes for all vitamins and most minerals are increased during pregnancy. Many physicians recommend that pregnant women receive multivitamin and mineral supplements, especially those pregnant women who do not consume an adequate diet and those in high-risk categories (i.e., women carrying more than one fetus, heavy cigarette smokers, and alcohol and drug abusers). {09} However, taking excessive amounts of multivitamin and mineral supplements may be harmful to the mother and/or fetus and should be avoided.
—Recommended intakes for most vitamins and minerals are increased during breast-feeding. {02}

Acceptance not established
There are insufficient data to show that selenium may reduce the occurrence of certain types of cancer. {24}


Pharmacology/Pharmacokinetics

Physicochemical characteristics:
Molecular weight—
    Elemental selenium: 78.96 {13}
    Selenious acid: 128.97 {12}

Mechanism of action/Effect:

Selenium is necessary for the enzyme glutathione perioxidase, which facilitates the lowering of tissue peroxide levels in the body by destroying hydrogen peroxide. {17} {18} There is an overlap in action of selenium and vitamin E in that both are responsible for lowering tissue peroxide levels. {03}

Absorption:

Readily absorbed. {03}


Storage

Selenium is stored primarily in red cells, liver, spleen, heart, nails, and tooth enamel, but also in testes and sperm. {03}

Elimination:
    Primarily in urine; to a lesser extent in the feces. {01}


Precautions to Consider

Pregnancy/Reproduction

Pregnancy—
Adequate and well controlled studies in humans have not been done and problems in humans have not been documented with intake of normal daily recommended amounts. {01}

High doses of selenium (15 to 30 micrograms per egg) have been found to cause adverse embryological effects in chickens. {01}

FDA Pregnancy Category C (parenteral selenium). {01}

Breast-feeding

Problems in humans have not been documented with intake of normal daily recommended amounts.

Pediatrics

Problems in pediatrics have not been documented with intake of normal daily recommended amounts.

Selenium injection that contains benzyl alcohol as a preservative should not be used in newborn and immature infants. The use of benzyl alcohol in neonates has been associated with a fatal toxic syndrome consisting of metabolic acidosis and central nervous system (CNS), respiratory, circulatory, and renal function impairment.


Geriatrics


Problems in geriatrics have not been documented with intake of normal daily recommended amounts.

Medical considerations/Contraindications
The medical considerations/contraindications included have been selected on the basis of their potential clinical significance (reasons given in parentheses where appropriate)— not necessarily inclusive (» = major clinical significance).


Risk-benefit should be considered when the following medical problems exist
Gastrointestinal disease and{01}
Renal function impairment{01}    (may cause high levels of selenium; reduction of dosage may be necessary {01} {25})



Patient monitoring
The following may be especially important in patient monitoring (other tests may be warranted in some patients, depending on condition; » = major clinical significance):

Selenium, plasma    (weekly plasma selenium monitoring may be recommended by some clinicians for patients receiving short-term total parenteral nutrition [TPN]; monthly monitoring may be recommended with long-term use {13} {21} {22})




Overdose
For more information on the management of overdose or unintentional ingestion, contact a Poison Control Center (see Poison Control Center Listing ).

Clinical effects of overdose


Side/Adverse Effects
Symptoms of overdose
    
Dermatitis (itching of skin){01}{11}
    
diarrhea {10}
    
fingernail weakening {01}
    
garlic odor of breath and sweat {01}
    
hair loss {01}{11}
    
irritability {10}
    
metallic taste {01}
    
nausea and vomiting {01}
    
unusual tiredness and weakness {10}




Patient Consultation
As an aid to patient consultation, refer to Advice for the Patient, Selenium Supplements (Systemic).

In providing consultation, consider emphasizing the following selected information (» = major clinical significance):

Description of use
Description should include function in the body, signs of deficiency, conditions that may cause deficiency of selenium


Importance of diet
Importance of proper nutrition; supplement may be needed because of inadequate dietary intake

Food sources of selenium

Recommended daily intake for selenium

Proper use of this dietary supplement

» Proper dosing
Missed dose: No cause for concern because of length of time necessary for depletion; remembering to take as directed

» Proper storage


General Dosing Information
Because of the infrequency of selenium deficiency alone, combinations of selenium with several vitamins and/or minerals are commonly administered. Many commercial vitamin-mineral complexes are available.

For parenteral dosage forms only
In most cases, parenteral administration is indicated only when oral administration is not acceptable (for example, in nausea, vomiting, preoperative and postoperative conditions) or possible (for example, in malabsorption syndromes or following gastric resection).

Diet/Nutrition
Recommended dietary intakes for selenium are defined differently worldwide.


For U.S.:
The Recommended Dietary Allowances (RDAs) for vitamins and minerals are determined by the Food and Nutrition Board of the National Research Council and are intended to provide adequate nutrition in most healthy persons under usual environmental stresses. In addition, a different designation may be used by the FDA for food and dietary supplement labeling purposes, as with Daily Value (DV). DV replaces the previous labeling terminology United States Recommended Daily Allowances (USRDAs). {02} {30}



For Canada:
Recommended Nutrient Intakes (RNIs) for vitamins, minerals, and protein are determined by Health and Welfare Canada and provide recommended amounts of a specific nutrient while minimizing the risk of chronic diseases. {31}


Daily recommended intakes for selenium are generally defined as follows {02} {31}


Infants and children—
Birth to 3 years: 10 to 20 mcg.

4 to 6 years: 20 mcg.

7 to 10 years: 30 mcg.



Adolescent and adult males—
40 to 70 mcg.



Adolescent and adult females—
45 to 55 mcg.



Pregnant females—
65 mcg.



Lactating females—
75 mcg.



The best sources of selenium include grains (depending on selenium content of soil), seafood, liver, and lean red meat. {02} {03}


SELENIOUS ACID


Parenteral Dosage Forms

SELENIOUS ACID INJECTION USP

Usual adult and adolescent dose
Deficiency (treatment)
Intravenous, 100 mcg a day of elemental selenium for 24 to 31 days, added to total parenteral nutrition (TPN). {01}

Deficiency (prophylaxis)
Intravenous, 20 to 40 mcg of elemental selenium a day, added to total parenteral nutrition (TPN). {01}


Usual pediatric dose
Deficiency (prophylaxis and treatment)
Intravenous, 3 mcg of elemental selenium per kilogram of body weight a day, added to total parenteral nutrition (TPN). {01} {23}

Note: Selenium injection that contains benzyl alcohol as a preservative should not be used in newborn and immature infants. The use of benzyl alcohol in neonates has been associated with a fatal toxic syndrome consisting of metabolic acidosis and CNS, respiratory, circulatory, and renal function impairment.



Strength(s) usually available
U.S.—


40 mcg elemental selenium per mL (Rx) [Sele-Pak (0.9% benzyl alcohol)] [Selepen (0.9% benzyl alcohol){26}][Generic]

Canada—
Not commercially available.

Packaging and storage:
Store below 40 °C (104 °F), preferably between 15 and 30 °C (59 and 86 °F), unless otherwise specified by manufacturer.

Preparation of dosage form:
Selenious acid is compatible with amino acids, dextrose, electrolytes, and other trace elements usually used for total parenteral nutrition (TPN). {01}


SELENIUM


Oral Dosage Forms

SELENIUM TABLETS

Usual adult and adolescent dose
Deficiency (prophylaxis)—Oral, amount based on normal daily recommended intakes {02} {31}
Adolescent and adult males—40 to 70 mcg.

Adolescent and adult females—45 to 55 mcg.

Pregnant females—65 mcg.

Lactating females—75 mcg.

Deficiency (treatment)
Treatment dose is individualized by prescriber based on severity of deficiency.


Usual pediatric dose
Deficiency (prophylaxis)—Oral, amount based on normal daily recommended intakes {02} {31}
Birth to 3 years of age—10 to 20 mcg.

4 to 6 years of age—20 mcg.

7 to 10 years of age—30 mcg.

Deficiency (treatment)
Treatment dose is individualized by prescriber based on severity of deficiency.


Strength(s) usually available
U.S.—


50 mcg elemental selenium (OTC)[Generic](yeast){14}{15}


100 mcg elemental selenium (OTC)[Generic]{27}{28}


200 mcg elemental selenium (OTC)[Generic]{27}{28}

Canada—


50 mcg elemental selenium (OTC)[Generic](yeast){16}


100 mcg elemental selenium (OTC)[Generic](yeast){16}

Note: Some strengths of these selenium preparations may exceed the dosage range recommended by USP DI Advisory Panels based on the amount necessary to meet normal nutritional needs.


Packaging and storage:
Store below 40 °C (104 °F), preferably between 15 and 30 °C (59 and 86 °F), unless otherwise specified by manufacturer.



Revised: 05/01/1995



References
  1. Selepen product information (LyphoMed—U.S.) Rev 1/89.
  1. National Research Council. Recommended dietary allowances. 10th ed. Washington DC: National Academy Press, 1989: 217–22.
  1. Linder M, editor. Nutritional biochemistry and metabolism with clinical applications. New York: Elsevier, 1991: 243–6.
  1. Fleming C, Lie J, McCall J et al. Selenium deficiency and fatal cardiomyopathy in a patient on home parenteral nutrition. Gastroenterology 1982; 83: 689–93.
  1. Johnson R, Baker S, Fallon J, et al. An accidental case of cardiomyopathy and selenium deficiency. N Engl J Med 1981: 304 (20): 1210–2.
  1. Brown M, Cohen H, Lyons J, et al. Proximal muscle weakness and selenium deficiency associated with long term parenteral nutrition. Am J Clin Nutr 1986; 43: 549–54.
  1. Kien C, Ganther H. Manifestations of chronic selenium deficiency in a child receiving total parenteral nutrition. Am J Clin Nutr 1983; 37: 319–28.
  1. Van Rij A, Thomson C, McKenzie J, Robinson M. Selenium deficiency in total parenteral nutrition. Am J Clin Nutr 1979; 32: 2076–85.
  1. Committee on Nutritional Status during Pregnancy, National Academy of Sciences. Washington DC: National Academy Press, 1990: 1-23.
  1. Helzlsourer K, Jacobs R, Morris S. Acute selenium intoxication in the United States. Fed Proc 44: 1670.
  1. Yan G, Wang S, Zhou R, Sun S. Endemic selenium intoxication of humans in China. Am J Clin Nutr 1983; 37: 872–81.
  1. Fleeger CA, editor. USAN 1993. USAN and the USP dictionary of drug names. Rockville, MD: The United States Pharmacopeial Convention, Inc., 1992.
  1. Nichoalds G. Selenium in Clinical Guide to Parenteral Micronutrition, First Edition.
  1. Selenium product information (Rexall—US) Rec 12/91.
  1. Selenium product information (Nature Made—US)
  1. Selenium product information (Jamieson—Canada).
  1. Ellenhorn MJ, Barceloux DG. Medical toxicology. Diagnosis and treatment of human poisoning. New York: Elsevier, 1988.
  1. Neve J. Physiological and nutritional importance of selenium. Experientia 1991; 47: 187–93.
  1. King W, Michel W, Malt R, et al. Reversal of selenium deficiency with oral selenium. N Engl J Med 1981; 304 (21): 1305.
  1. Keshan Disease Research Group of the Chinese Academy of Medical Sciences. Observations on effect of sodium selenite in prevention of Keshan Disease. Chin Med J 1979; 29(7): 471–6.
  1. Litov R, Combs G. Selenium in pediatric nutrition. Pediatrics 1991: 87(3): 339–51.
  1. Levander O, Burk R. Report on the 1986 A.S.P.E.N research workshop on selenium in clinical nutrition. JPEN 1986; 10: 545–9.
  1. Panelist comment, 1992.
  1. Panel consensus, 1992.
  1. Panelists comment, 1992.
  1. Olin BR, editor. Drug facts and comparisons. St. Louis: Facts and Comparisons Inc, September 1992: 49e.
  1. Redbook 1993. Montvale, NJ: Medical Economics Data, 1993: 500.
  1. Redbook 1993. Montvale, NJ: Medical Economics Data, 1993: 501.
  1. Per phone call (Major—US), 12/6/93.
  1. Food and Drug Administration. Focus on food labeling. FDA Consumer. May, 1993.
  1. Health and Welfare Canada. Nutrition recommendations, the report of the scientific committee. Ottawa Canada: Canadian Government Publishing Centre, 1990: 11-2.
  1. Nutrition and Electrolytes Panel Meeting, 1/95.
Hide
(web4)