VITESEL INJECTION

Mechanism of action

Selenate acts by being reduced in the body to selenite and subsequently to hydrogen selenide (H2Se), which is the bioactive form of selenium. This reduction process is vital for the incorporation of selenium into selenoproteins, which are important for various biological functions, including antioxidant defense. The selenate reduction pathway involves several enzymes and is linked to amino acid metabolism and the synthesis of selenoamino acids.

Pharmacodynamics

Selenate exhibits its pharmacological effects mainly through its role in the synthesis of selenoproteins, which are crucial for maintaining cellular redox balance and protecting against oxidative stress. These selenoproteins, including glutathione peroxidases and thioredoxin reductases, contribute to the detoxification of reactive oxygen species and the regulation of various metabolic processes.

Pharmacokinetics

Following administration, selenate is absorbed in the gastrointestinal tract, where it undergoes a series of metabolic transformations. It is reduced to selenite and then to hydrogen selenide, which is incorporated into selenoproteins. The bioavailability of selenate can be influenced by dietary factors and the presence of other selenium sources. The elimination half-life and urinary excretion patterns of selenate may vary depending on individual metabolism and selenium status.

Pregnancy

Selenate should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

It is unknown whether selenate is excreted in human milk. Caution should be exercised when administering to breastfeeding women.

Storage

Store in a cool, dry place away from light. Keep out of reach of children.

Indications

• Prevention of vitamin E deficiency
• Antioxidant therapy
• Support in conditions related to oxidative stress

Dosage

Children: Refer to BNF for Children for specific dosage guidelines.

Adults: Refer to BNF for specific dosage guidelines.

Mechanism of action

Tocopherol acts as a radical scavenger, primarily functioning as an antioxidant for lipid bilayers. It donates hydrogen atoms to free radicals, trapping them and preventing cellular damage. Its effectiveness is influenced by its location within the membrane and its interaction with cytosolic reductants like ascorbate. Tocopherol can trap multiple radicals, including alkyl and peroxy radicals.

Pharmacodynamics

The antioxidant properties of tocopherol lead to significant pharmacodynamic effects, including the inhibition of cell death through modulation of protein kinase C (PKC). Tocopherol also exhibits anti-inflammatory effects, which can be attributed to its influence on cytokines, prostaglandins, prostanoids, and thromboxanes. These interactions may contribute to its protective effects in various pathological conditions.

Pharmacokinetics

Tocopherol is absorbed in the intestines and its bioavailability can be influenced by dietary fat intake. It is transported in the plasma primarily bound to lipoproteins. Tocopherol is stored in adipose tissue and the liver, and its elimination occurs through bile and urine. The half-life of tocopherol can vary depending on the individual's nutritional status and other factors.

Pregnancy

Tocopherol is generally considered safe during pregnancy, but it is advisable to consult a healthcare provider before use.

Breast-feeding

Tocopherol is excreted in breast milk, and while it is considered safe, a healthcare provider should be consulted for specific recommendations.

Storage

Store in a cool, dry place away from direct sunlight.

Mechanism of action

Tocopherol acts as a radical scavenger. It mainly acts as an antioxidant for lipid bilayers. Tocopherol's functions depend on the H-atom donating ability, location, and movement within the membrane, as well as the efficiency in the radical recycling by some cytosolic reductants such as ascorbate. Tocopherol actions are related to the trap of radicals, and it has been shown that even in the absence of substituents in the ortho-positions, tocopherol can trap more than two radicals. The type of radicals available for tocopherol are alkyl and peroxy.

Pharmacodynamics

The antioxidant effects of tocopherol can be translated into different changes at the pharmacodynamic level. In vitro studies have shown that this antioxidant activity can produce modification in protein kinase C (PKC) which will later be translated into an inhibition of cell death. Some other derivate effects are the anti-inflammatory properties of tocopherol which can be related to the modulation of cytokines or prostaglandins, prostanoids and thromboxanes.