Iron supplements
Encyclopedia
Iron supplements are supplements
that can be prescribed by a doctor for a medical reason. Iron
can also be a dietary supplement
, which can be purchased in supermarkets etc. These two categories should not be confused.
The first iron pills were commonly known as Blaud's pills, which were named after P. Blaud of Beaucaire, the French physician who introduced and started the use of these medications as a treatment for patients with anemia
.
to treat iron-deficiency
anemia
.
First, it must be clear that iron deficiency and not another factor (e.g. chronic, low-grade, undetected blood loss such as fecal occult blood
) causes the anemia. Preventive measures must be discussed with the patient (for example when the patient is on a strict vegetarian diet because inorganic iron in plants has a lower bioavailability
, or elderly patients with a poor diet).
Another indication for giving extra iron is the second and third trimester of pregnancy
, generally in association with folic acid
. Indeed, in some condition like growth, menstruation and pregnancy, the body's need for iron is increased. Supplements may be needed to reach RDA life goals.
Patients at risk of acute complications of iron supplementation may be candidates for blood transfusion
, which decreases the need of iron for hemoglobin synthesis, and supplies additional iron when the transfused hemoglobin is degraded. Patients with anemia of chronic disease
may benefit from erythropoietin
.
(this is the most common and cheapest salt
, e.g. Feratab, Fer-Iron, Slow-FE,…) and in complex with gluconate, dextran
, carbonyl iron
, and other salts. Sometimes ascorbic acid
is added for better absorption.
Heme iron polypeptide can be used when regular iron supplements such as ferrous sulfate or ferrous fumarate are not tolerated or absorbed. A clinical study demonstrated that HIP increased serum iron levels 23 times greater than ferrous fumarate on a milligram-per-milligram basis.
Another alternative is ferrous glycine
sulfate
or ferroglycine sulfate, has less gastrointestinal side-effects than standard preparations such as iron fumarate, but is more expensive. It is especially useful in iron deficiency anemia associated with autoimmune gastritis and Helicobacter pylori
gastritis, where it generally has satisfactory effect.
Since iron stores in the body are generally depleted, and there is a limit to what the body can process (about 100mg per day) without iron poisoning
, this is a chronic therapy which may take 3-6 months.
iron therapy (intravenously or intramuscular) is only given when oral therapy has failed or oral absorption is seriously compromised (by illnesses, or when the patient cannot swallow) and benefit from oral therapy cannot be expected. Parenteral therapy is more expensive, has increased morbidity and might not be suitable during pregnancy. In cases of persistent iron deficiency (renal replacement therapy, inflammatory bowel disease), the benefits of parenteral iron far outweigh the risks.
One formulation of parenteral iron is iron dextran (trade names including Cosmofer, DexFerrum, Infed). A notable side effect is allergic reaction, which occurs in less than 1 on 100 treated patients, but may cause severe, sometimes fatal, complications, including loss of consciousness, collapse, difficulty breathing, hives, swelling, convulsions and severe low blood pressure (hypotension
).
Iron saccharose (trade names including Venofer) has an occurrence of allergic reactions of less than 1 in 1000. A common side effect is taste changes, especially a metallic taste, occurring in between 1 in 10 and 1 in 100 treated patients.
or constipation
and epigastric abdominal discomfort. Taken after a meal, side effects decrease, but there is an increased risk of interaction with other substances. Side effects are dose-dependent, and the dose may be adjusted.
The patient may notice that his/her stools become black. This is completely harmless, but patients must be warned about this to avoid unnecessary concern. When iron supplements are given in a liquid form, teeth may reversibly discolor (this can be avoided through the use of a straw). Intramuscular injection can be painful, and brown discoloration may be noticed.
Treatments with iron(II) sulfate
have higher incidence of adverse events than iron(III)-hydroxide polymaltose complex (IPC) or iron bis-glycinate chelate.
and anemias without proper work-up (i.e., documentation of iron deficiency). Hypersensitivity reactions can be very dramatic if iron is administered intravenously.
(an acute phase reaction protein) in acute infections is thought to be to sequester iron from bacteria, it is generally thought that iron supplementation (which circumvents this mechanism) should be avoided in patients who have active bacterial infections. Replacement of iron stores is seldom such an emergency situation that it cannot wait for any such acute infection to be treated.
Some studies have found that iron supplementation can lead to an increase in infectious disease
morbidity in areas where bacterial infections are common. For example, children receiving iron-enriched foods have demonstrated an increased rate in diarrhea
overall and enteropathogen shedding. Iron deficiency protects against infection by creating an unfavorable environment for bacterial growth. Nevertheless, while iron deficiency might lessen infections by certain pathogenic diseases, it also leads to a reduction in resistance to other strains of viral or bacterial infections, such as Salmonella typhimurium or Entamoeba histolytica
. Overall, it is sometimes difficult to decide whether iron supplementation will be beneficial or harmful to an individual in an environment that is prone to many infectious diseases; however this is a different question than the question of supplementation in individuals who are already ill with a bacterial infection.
, methyldopa
, levodopa
, bisphosphonates and quinolones. The same can occur with elements in food, such as calcium
. Absorption of iron is better at a low pH (an acid environment), and resorption is decreased if there is a simultaneous intake of antacids, phosphates, etc.
Tannins from foods, such as tea
and saw palmetto
, reduce absorption of iron.
Taken after a meal, there are fewer side effects but there is also less absorption because of interaction and pH alteration. Generally, an interval of 2-3h between the iron intake and that of other drugs seems advisable.
percentage, MCV
, MCH
and MCHC (the latter three being signs of microcytic anemia
) should increase.
Dietary supplement
A dietary supplement, also known as food supplement or nutritional supplement, is a preparation intended to supplement the diet and provide nutrients, such as vitamins, minerals, fiber, fatty acids, or amino acids, that may be missing or may not be consumed in sufficient quantities in a person's diet...
that can be prescribed by a doctor for a medical reason. Iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
can also be a dietary supplement
Dietary supplement
A dietary supplement, also known as food supplement or nutritional supplement, is a preparation intended to supplement the diet and provide nutrients, such as vitamins, minerals, fiber, fatty acids, or amino acids, that may be missing or may not be consumed in sufficient quantities in a person's diet...
, which can be purchased in supermarkets etc. These two categories should not be confused.
The first iron pills were commonly known as Blaud's pills, which were named after P. Blaud of Beaucaire, the French physician who introduced and started the use of these medications as a treatment for patients with anemia
Anemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
.
Indications
Iron supplements are used in medicineMedicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
to treat iron-deficiency
Iron deficiency (medicine)
Iron deficiency is one of the most common of the nutritional deficiencies. Iron is present in all cells in the human body, and has several vital functions...
anemia
Anemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
.
First, it must be clear that iron deficiency and not another factor (e.g. chronic, low-grade, undetected blood loss such as fecal occult blood
Fecal occult blood
Fecal occult blood refers to blood in the feces that is not visibly apparent. A fecal occult blood test checks for hidden blood in the stool...
) causes the anemia. Preventive measures must be discussed with the patient (for example when the patient is on a strict vegetarian diet because inorganic iron in plants has a lower bioavailability
Bioavailability
In pharmacology, bioavailability is a subcategory of absorption and is used to describe the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. By definition, when a medication is administered...
, or elderly patients with a poor diet).
Another indication for giving extra iron is the second and third trimester of pregnancy
Pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
, generally in association with folic acid
Folic acid
Folic acid and folate , as well as pteroyl-L-glutamic acid, pteroyl-L-glutamate, and pteroylmonoglutamic acid are forms of the water-soluble vitamin B9...
. Indeed, in some condition like growth, menstruation and pregnancy, the body's need for iron is increased. Supplements may be needed to reach RDA life goals.
Patients at risk of acute complications of iron supplementation may be candidates for blood transfusion
Blood transfusion
Blood transfusion is the process of receiving blood products into one's circulation intravenously. Transfusions are used in a variety of medical conditions to replace lost components of the blood...
, which decreases the need of iron for hemoglobin synthesis, and supplies additional iron when the transfused hemoglobin is degraded. Patients with anemia of chronic disease
Anemia of chronic disease
Anemia of chronic disease, also referred to as anemia of inflammatory response is a form of anemia seen in chronic illness, e.g. from chronic infection, chronic immune activation, or malignancy...
may benefit from erythropoietin
Erythropoietin
Erythropoietin, or its alternatives erythropoetin or erthropoyetin or EPO, is a glycoprotein hormone that controls erythropoiesis, or red blood cell production...
.
Oral
Iron can be supplemented by the oral route using various pharmacological forms, such as iron(II) sulfateIron(II) sulfate
Iron sulfate or ferrous sulfate is the chemical compound with the formula FeSO4. Known since ancient times as copperas and as green vitriol, the blue-green heptahydrate is the most common form of this material...
(this is the most common and cheapest salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
, e.g. Feratab, Fer-Iron, Slow-FE,…) and in complex with gluconate, dextran
Dextran
Dextran is a complex, branched glucan composed of chains of varying lengths...
, carbonyl iron
Carbonyl iron
Carbonyl iron is a highly pure iron, prepared by chemical decomposition of purified iron pentacarbonyl. It usually has the appearance of grey powder, composed of spherical microparticles. Most of the impurities are carbon, oxygen, and nitrogen.BASF invented carbonyl iron powder in 1925, and claims...
, and other salts. Sometimes ascorbic acid
Ascorbic acid
Ascorbic acid is a naturally occurring organic compound with antioxidant properties. It is a white solid, but impure samples can appear yellowish. It dissolves well in water to give mildly acidic solutions. Ascorbic acid is one form of vitamin C. The name is derived from a- and scorbutus , the...
is added for better absorption.
Heme iron polypeptide can be used when regular iron supplements such as ferrous sulfate or ferrous fumarate are not tolerated or absorbed. A clinical study demonstrated that HIP increased serum iron levels 23 times greater than ferrous fumarate on a milligram-per-milligram basis.
Another alternative is ferrous glycine
Glycine
Glycine is an organic compound with the formula NH2CH2COOH. Having a hydrogen substituent as its 'side chain', glycine is the smallest of the 20 amino acids commonly found in proteins. Its codons are GGU, GGC, GGA, GGG cf. the genetic code.Glycine is a colourless, sweet-tasting crystalline solid...
sulfate
Sulfate
In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...
or ferroglycine sulfate, has less gastrointestinal side-effects than standard preparations such as iron fumarate, but is more expensive. It is especially useful in iron deficiency anemia associated with autoimmune gastritis and Helicobacter pylori
Helicobacter pylori
Helicobacter pylori , previously named Campylobacter pyloridis, is a Gram-negative, microaerophilic bacterium found in the stomach. It was identified in 1982 by Barry Marshall and Robin Warren, who found that it was present in patients with chronic gastritis and gastric ulcers, conditions that were...
gastritis, where it generally has satisfactory effect.
Since iron stores in the body are generally depleted, and there is a limit to what the body can process (about 100mg per day) without iron poisoning
Iron poisoning
Iron poisoning is an iron overload caused by a large excess of iron intake and usually refers to an acute overload rather than a gradual one. The terms has been primarily associated with young children who consumed large quantities of iron supplement pills, which resemble sweets and are widely...
, this is a chronic therapy which may take 3-6 months.
Parenteral
ParenteralParenteral
Parenteral is a route of administration that involves piercing the skin or mucous membrane. Parenteral nutrition refers to providing nutrition via the veins.-Etymology:...
iron therapy (intravenously or intramuscular) is only given when oral therapy has failed or oral absorption is seriously compromised (by illnesses, or when the patient cannot swallow) and benefit from oral therapy cannot be expected. Parenteral therapy is more expensive, has increased morbidity and might not be suitable during pregnancy. In cases of persistent iron deficiency (renal replacement therapy, inflammatory bowel disease), the benefits of parenteral iron far outweigh the risks.
One formulation of parenteral iron is iron dextran (trade names including Cosmofer, DexFerrum, Infed). A notable side effect is allergic reaction, which occurs in less than 1 on 100 treated patients, but may cause severe, sometimes fatal, complications, including loss of consciousness, collapse, difficulty breathing, hives, swelling, convulsions and severe low blood pressure (hypotension
Hypotension
In physiology and medicine, hypotension is abnormally low blood pressure, especially in the arteries of the systemic circulation. It is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the...
).
Iron saccharose (trade names including Venofer) has an occurrence of allergic reactions of less than 1 in 1000. A common side effect is taste changes, especially a metallic taste, occurring in between 1 in 10 and 1 in 100 treated patients.
Side effects
Side effects of therapy with iron are most often diarrheaDiarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
or constipation
Constipation
Constipation refers to bowel movements that are infrequent or hard to pass. Constipation is a common cause of painful defecation...
and epigastric abdominal discomfort. Taken after a meal, side effects decrease, but there is an increased risk of interaction with other substances. Side effects are dose-dependent, and the dose may be adjusted.
The patient may notice that his/her stools become black. This is completely harmless, but patients must be warned about this to avoid unnecessary concern. When iron supplements are given in a liquid form, teeth may reversibly discolor (this can be avoided through the use of a straw). Intramuscular injection can be painful, and brown discoloration may be noticed.
Treatments with iron(II) sulfate
Iron(II) sulfate
Iron sulfate or ferrous sulfate is the chemical compound with the formula FeSO4. Known since ancient times as copperas and as green vitriol, the blue-green heptahydrate is the most common form of this material...
have higher incidence of adverse events than iron(III)-hydroxide polymaltose complex (IPC) or iron bis-glycinate chelate.
Contraindications
Documented hypersensitivityHypersensitivity
Hypersensitivity refers to undesirable reactions produced by the normal immune system, including allergies and autoimmunity. These reactions may be damaging, uncomfortable, or occasionally fatal. Hypersensitivity reactions require a pre-sensitized state of the host. The four-group classification...
and anemias without proper work-up (i.e., documentation of iron deficiency). Hypersensitivity reactions can be very dramatic if iron is administered intravenously.
Iron supplementation and infection risk
Because one of the functions of elevated ferritinFerritin
Ferritin is a ubiquitous intracellular protein that stores iron and releases it in a controlled fashion. The amount of ferritin stored reflects the amount of iron stored. The protein is produced by almost all living organisms, including bacteria, algae and higher plants, and animals...
(an acute phase reaction protein) in acute infections is thought to be to sequester iron from bacteria, it is generally thought that iron supplementation (which circumvents this mechanism) should be avoided in patients who have active bacterial infections. Replacement of iron stores is seldom such an emergency situation that it cannot wait for any such acute infection to be treated.
Some studies have found that iron supplementation can lead to an increase in infectious disease
Infectious disease
Infectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...
morbidity in areas where bacterial infections are common. For example, children receiving iron-enriched foods have demonstrated an increased rate in diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
overall and enteropathogen shedding. Iron deficiency protects against infection by creating an unfavorable environment for bacterial growth. Nevertheless, while iron deficiency might lessen infections by certain pathogenic diseases, it also leads to a reduction in resistance to other strains of viral or bacterial infections, such as Salmonella typhimurium or Entamoeba histolytica
Entamoeba histolytica
Entamoeba histolytica is an anaerobic parasitic protozoan, part of the genus Entamoeba. Predominantly infecting humans and other primates, E. histolytica is estimated to infect about 50 million people worldwide...
. Overall, it is sometimes difficult to decide whether iron supplementation will be beneficial or harmful to an individual in an environment that is prone to many infectious diseases; however this is a different question than the question of supplementation in individuals who are already ill with a bacterial infection.
Interactions
Iron forms an insoluble complex with several other drugs, resulting in decreased absorption of both iron and the other drug. Examples include tetracycline, penicillaminePenicillamine
Penicillamine is a pharmaceutical of the chelator class. It is sold under the trade names of Cuprimine and Depen. The pharmaceutical form is D-penicillamine, as L-penicillamine is toxic...
, methyldopa
Methyldopa
Methyldopa is an alpha-adrenergic agonist psychoactive drug used as a sympatholytic or antihypertensive. Its use is now mostly deprecated following the introduction of alternative safer classes of agents...
, levodopa
Levodopa
L-DOPA is a chemical that is made and used as part of the normal biology of some animals and plants. Some animals including humans make it via biosynthesis from the amino acid L-tyrosine. L-DOPA is the precursor to the neurotransmitters dopamine, norepinephrine , and epinephrine collectively...
, bisphosphonates and quinolones. The same can occur with elements in food, such as calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
. Absorption of iron is better at a low pH (an acid environment), and resorption is decreased if there is a simultaneous intake of antacids, phosphates, etc.
Tannins from foods, such as tea
Tea
Tea is an aromatic beverage prepared by adding cured leaves of the Camellia sinensis plant to hot water. The term also refers to the plant itself. After water, tea is the most widely consumed beverage in the world...
and saw palmetto
Saw Palmetto
Serenoa repens, commonly known as saw palmetto, is the sole species currently classified in the genus Serenoa. It has been known by a number of synonyms, including Sabal serrulatum, under which name it still often appears in alternative medicine. It is a small palm, normally reaching a height of...
, reduce absorption of iron.
Taken after a meal, there are fewer side effects but there is also less absorption because of interaction and pH alteration. Generally, an interval of 2-3h between the iron intake and that of other drugs seems advisable.
Precautions
Children who ingest tablets may become intoxicated, in which case they should be taken to an emergency department. Some formulations (like carbonyl-iron) may be safer.Follow-up
Follow-up is needed to ensure compliance and to detect adequate response to therapy. If not, this may indicate another cause of anemia. Haematocrit, reticulocyteReticulocyte
Reticulocytes are immature red blood cells, typically composing about 1% of the red cells in the human body.Reticulocytes develop and mature in the red bone marrow and then circulate for about a day in the blood stream before developing into mature red blood cells. Like mature red blood cells,...
percentage, MCV
Mean corpuscular volume
The mean corpuscular volume, or "mean cell volume" , is a measure of the average red blood cell size that is reported as part of a standard complete blood count....
, MCH
MCH
MCH can refer to:* Machala, Ecuador * March, in National Rail abbreviations.* March railway station, England; National Rail station code MCH.* Mean corpuscular hemoglobin or Mean cell hemoglobin* Maternal and child health...
and MCHC (the latter three being signs of microcytic anemia
Microcytic anemia
Microcytic anemia is a generic term for any type of anemia characterized by small red blood cells. The normal mean corpuscular volume is 76-100 fL, with smaller cells as macrocytic....
) should increase.
See also
- Human iron metabolismHuman iron metabolismHuman iron metabolism is the set of chemical reactions maintaining human homeostasis of iron. Iron is an essential element for most life on Earth, including human beings. The control of this necessary but potentially toxic substance is an important part of many aspects of human health and disease...
- ProferrinProferrinProferrin is an oral iron supplement made from heme iron polypeptide used to treat iron deficiency anemia. Compared to other iron supplements such as ferrous fumarate, ferrous sulphate and ferrous gluconate, Proferrin has shown to not cause high gastrointestinal side effects associated with oral...
- GeritolGeritolGeritol is a US trademarked name for various dietary supplements, past and present. Geritol is currently a brand name for several vitamin complexes plus iron or multimineral products in both liquid form and tablets, containing from 9.5 to 18 mg of iron per daily dose...
- iron deficiency
- iron deficiency anemiaIron deficiency anemiaIron-deficiency anemia is a common anemia that occurs when iron loss occurs, and/or the dietary intake or absorption of iron is insufficient...