RiteMED Vitamin B-Complex + Iron + Buclizine HCl Mechanism of Action

Pharmacologic Category: Appetite stimulant.
Pharmacology: Pharmacodynamics: Buclizine Hydrochloride: The mechanism of buclizine's appetite stimulating action is not known.
Thiamine Mononitrate (Vitamin B₁): Thiamine plays an essential role as a cofactor in key reactions in carbohydrate metabolism. It acts in two types of reactions upon conversion into the coenzyme thiamine pyrophosphate (TPP): oxidative decarboxylation and transketolation. These reactions are vital in carbohydrate metabolism, specifically in the citric acid cycle (Krebs cycle) and the pentose pathway.
Thiamine assists in blood formation and nerve transmission. It is also involved in the conversion of the amino acid tryptophan to the vitamin niacin and the metabolism of the branched-chain amino acids leucine, isoleucine and valine.
Pyridoxine Hydrochloride (Vitamin B₆): Pyridoxine is converted to its active forms, pyridoxal phosphate (PLP) and pyridoxamine phosphate (PMP). PLP facilitates more than 100 different enzymatic reactions that support protein metabolism, blood synthesis, carbohydrate metabolism, and neurotransmitter synthesis. It helps produce a number of neurotransmitters including serotonin, gamma amino butyric acid (GABA), dopamine, and epinephrine.
Pyridoxine supports the synthesis of white blood cells of the immune system and is crucial for the synthesis of the red blood cells' hemoglobin rings, which carry oxygen to hemoglobin. Inadequate vitamin B₆ disturbs the binding of oxygen to hemoglobin, causing microcytic hypochromic anemia. In this type of anemia, red blood cells are smaller than normal and also lack sufficient hemoglobin to carry oxygen.
Cyanocobalamin (Vitamin B₁₂): Cyanocobalamin plays a key role in folate metabolism by transferring a methyl group from the folate coenzyme tetrahydrofolic acid (THFA), which is important in many metabolic pathways. Cyanocobalamin is required in the synthesis of myelin, the white sheath of lipoprotein that surrounds many nerve fibers. During cyanocobalamin deficiency, progressive demyelination of nerve fibers occurs, leading to a variety of neurological symptoms.
Cyanocobalamin is involved in biochemical processes essential for DNA synthesis. A cellular deficiency of vitamin B₁₂ can impair DNA synthesis for growth and division of cells. The lack of DNA affects red blood cells which rapidly turnover every 120 days. When red blood cell precursors in the bone marrow are not able to form new DNA, they cannot divide normally to become red blood cells. As these precursor cells continue to synthesize protein and other cell components, they grow into large, fragile, immature cells which displace red blood cells and cause megaloblastic anemia.
Iron (as Ferrous Fumarate): Iron is essential in the formation of healthy red blood cells. It is a component of two heme proteins: hemoglobin and myoglobin. Hemoglobin in muscles facilitates the movement of oxygen in muscle cells. Iron also acts as a cofactor of enzymes involved in energy metabolism. Cytochromes, for example, are heme-containing compounds critical to the electron transport chain. Iron also has immune-enhancing and cognition-enhancing properties.
Pharmacokinetics: Buclizine Hydrochloride: Antihistamines such as buclizine hydrochloride are generally well absorbed following oral administration.
The distribution of most antihistamines has not been fully characterized. Highest concentrations are observed in the spleen, kidneys, brain, muscle, and skin. Protein binding of antihistamines range from 50% to 99%.
Antihistamines appear to be extensively metabolized mainly in the liver and are excreted in the urine as inactive metabolites within 24 hours. Negligible amounts of antihistamines are excreted unchanged in the urine.
Thiamine Mononitrate (Vitamin B₁): Thiamine is readily absorbed in the jejunum by active transport and passive diffusion mechanisms. It is transported by the portal and systemic circulations to the liver and to various tissues in the body. Thiamine is metabolized in the liver and excreted in the urine.
Pyridoxine Hydrochloride (Vitamin B₆): Pyridoxine is readily absorbed from the jejunum after oral administration. It is stored mainly in the liver and in lesser amounts in the muscle and brain. Pyridoxine is converted to the active forms pyridoxal phosphate and pyridoxamine phosphate. In the liver, pyridoxal is oxidized to 4-pyridoxic acid which is excreted in the urine.
Cyanocobalamin (Vitamin B₁₂): Cyanocobalamin binds to intrinsic factor, a glycoprotein produced by the gastric mucosa, and is then actively absorbed from the gastrointestinal tract (GIT). Absorption from the GIT can also occur by passive diffusion; little of the vitamin present is absorbed in this manner although the process becomes increasingly important with larger amounts such as those used therapeutically. Cyanocobalamin is extensively bound to transcobalamin which is involved in the rapid transport of the cobalamins to tissues. Cyanocobalamin is stored in the liver, excreted in the bile, and undergoes extensive enterohepatic recycling; part of the administered dose is excreted in the urine.
Iron (as Ferrous Fumarate): Iron is irregularly and incompletely absorbed from the gastrointestinal tract, the main sites of absorption being the duodenum and jejunum. Absorption is also increased in conditions of iron deficiency or in the fasting state but is decreased if the body stores are overloaded. Only 5 to 15% of the iron ingested in food is usually absorbed. About 33% of iron is absorbed from every 100 mg of iron from ferrous fumarate.
After absorption, the majority of iron is bound to transferrin and transported to the bone marrow where it is incorporated to hemoglobin. In the absence of bleeding (including menstruation), only a small amount of iron is lost daily. The majority of losses occur through the desquamation of the cells of the gastrointestinal tract and smaller amounts are lost through the skin and the urine.