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Indications

• Management of photosensitivity reactions
• Erythropoietic protoporphyria

Dosage

Children: Child 1–4 years: 60–90 mg daily, Child 5–8 years: 90–120 mg daily, Child 9–11 years: 120–150 mg daily, to be given as a single dose or in divided doses.

Adults: Refer to the BNF for specific dosing guidelines.

Mechanism of action

Betacarotene acts as an antioxidant and a precursor to vitamin A, which plays a critical role in cellular function, vision, growth, immune function, and skin health.

Pharmacodynamics

As a provitamin, betacarotene is converted to retinol (vitamin A) in the body, supporting various biological functions, including the maintenance of epithelial tissues and the modulation of immune responses.

Pharmacokinetics

Betacarotene is absorbed from the gastrointestinal tract and is stored in the liver. Its absorption can be influenced by dietary fat intake. It is primarily metabolized in the liver and has a relatively long half-life due to its storage in fat tissues.

Pregnancy

Safety in pregnancy has not been established; use only if clearly needed.

Breast-feeding

Excretion in breast milk is unknown; use with caution.

Storage

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

Formulations

• Oral preparations containing beta-carotene

Indications

• Improvement of visual function
• Support for eye health
• Management of diabetic retinopathy
• Enhancement of microcirculation
• Support for cardiovascular health

Dosage

Children: Consult a healthcare provider for appropriate dosing in children, as specific pediatric dosing may not be established.

Adults: Refer to specific product guidelines or consult a healthcare provider for dosing information, as it can vary based on formulation.

Mechanism of action

Bilberry is thought to exert its effects primarily through the action of anthocyanins, which have been shown to improve visual function and circulation. These compounds may enhance the integrity of the vascular system, inhibit oxidative stress, and improve microcirculation, particularly in the retina, thus potentially aiding in conditions like night blindness and age-related macular degeneration.

Pharmacodynamics

The pharmacodynamic effects of bilberry are largely attributed to its antioxidant properties, which help to scavenge free radicals and reduce oxidative damage in tissues. The anthocyanins in bilberry may also modulate inflammatory responses and improve endothelial function, contributing to better blood flow and reduced risk of cardiovascular complications.

Pharmacokinetics

Bilberry extracts are typically administered orally, and the active constituents are absorbed in the gastrointestinal tract. The bioavailability of anthocyanins can be influenced by factors such as food intake and gastrointestinal pH. Once absorbed, these compounds are metabolized in the liver and excreted primarily through urine. The half-life of bilberry components varies and is influenced by the specific anthocyanins and the formulation used.

Adverse effects

• Gastrointestinal upset
• Allergic reactions
• Headache
• Dizziness

Interactions

• Anticoagulants
• Antiplatelet drugs
• Diabetes medications

Precautions

• Use with caution in individuals with bleeding disorders
• Caution in patients undergoing surgery due to potential bleeding effects

Pregnancy

Bilberry is classified as safe for use during pregnancy, but it should be used under the guidance of a healthcare provider.

Breast-feeding

There is insufficient reliable information regarding the safety of bilberry during breastfeeding, thus caution is advised.

Storage

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

Formulations

• Dried berries
• Powdered extract
• Capsules
• Liquid extract

Indications

• General wellness support
• Anti-inflammatory effects
• Antioxidant activity
• Digestive aid
• Support for immune function

Dosage

Children: Paediatric dosing should be determined based on the specific extract and its intended use. Consultation with a healthcare provider is recommended for accurate dosing.

Adults: Dosage varies widely depending on the specific extract and formulation. It is essential to follow the manufacturer's instructions or consult a healthcare professional for appropriate dosing.

Mechanism of action

The mechanism of action of herbal extracts can vary significantly based on their constituents. Commonly, they exert their effects through multiple pathways including modulation of neurotransmitter systems, interference with inflammatory processes, or direct antioxidant activity. Some extracts may activate certain receptors or inhibit enzymes related to disease processes.

Pharmacodynamics

The pharmacodynamics of extracts is complex due to the presence of multiple active compounds which can have synergistic or antagonistic effects. These compounds may influence cellular signaling pathways, alter gene expression, or modulate immune response. The overall pharmacological profile is determined by the specific composition of the extract, its concentration, and the biological target it interacts with.

Pharmacokinetics

The pharmacokinetics of extracts involves absorption, distribution, metabolism, and excretion of the active compounds. Generally, herbal extracts are absorbed in the gastrointestinal tract, with bioavailability influenced by factors such as formulation, the presence of food, and individual metabolic differences. Compounds may undergo hepatic metabolism, and elimination can occur through urine or feces, depending on their chemical nature.

Pregnancy

Consult a healthcare professional before use, as the safety of the extract during pregnancy has not been established.

Breast-feeding

Consult a healthcare professional before use, as the safety of the extract during breastfeeding has not been established.

Storage

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

Indications

• Age-related Macular Degeneration (AMD)
• Cataracts
• Ocular health protection
• Antioxidant support

Dosage

Children: Refer to BNF for Children for specific dosage guidance as it may vary based on formulation and clinical indication.

Adults: Refer to BNF for specific dosage guidance as it may vary based on formulation and clinical indication.

Mechanism of action

Lutein exhibits antioxidant activity by reacting with active oxygen species, leading to the production of biologically active degradation products. It inhibits the peroxidation of membrane phospholipids and reduces lipofuscin formation, which are key contributors to oxidative stress. Additionally, lutein filters blue light and near-ultraviolet radiation, providing protective effects in the retina due to its ability to scavenge reactive oxygen species. It also enhances the expression of connexin-43, facilitating gap junctional communication and offering potential protection against cancer.

Pharmacodynamics

Lutein is concentrated in the macula of the retina, where it exerts protective effects against oxidative stress and high-energy light. Its presence is linked to a decreased risk of developing eye diseases such as Age-related Macular Degeneration (AMD). Studies indicate that higher macular pigment density is associated with a reduced risk of these conditions, highlighting lutein's role in maintaining eye health.

Pharmacokinetics

Lutein is absorbed in the gastrointestinal tract and its bioavailability can be influenced by the presence of dietary fats. It is transported in the bloodstream primarily via lipoproteins and is distributed to various tissues, with a significant accumulation in the retina and lenses of the eyes. The elimination half-life and metabolic pathways are not well characterized, but lutein is known to be more stable against degradation by pro-oxidants compared to other carotenoids.

Pregnancy

Lutein is generally considered safe during pregnancy, but consult a healthcare provider for individual assessment.

Breast-feeding

Lutein is likely safe during breastfeeding, but it is advisable to consult a healthcare provider.

Storage

Store in a cool, dry place away from light.

Formulations

• Supplement capsules
• Softgel formulations
• Powdered forms for mixing

Mechanism of action

Beta-carotene is an antioxidant that presents significant efficacy against the reactive oxygen species singlet oxygen. Beta-carotene acts as a scavenger of lipophilic radicals within the membranes of every cell compartments. It also presents an oxidative modification of LDL. The presence of long chains of conjugated double bonds is responsible for its antioxidative properties by allowing beta-carotene to chelate oxygen-free radicals and dissipate their energy. The chelation of free radicals inhibits the peroxidation of lipids. The effect of beta-carotene in the immune response is thought to be related to the direct effect on the thymus which increases the production of immune cells. IN HEMATOPORPHYRIN PHOTOSENSITIZED MICE BETA-CAROTENE SHOWED PHOTOPROTECTION WAS DUE TO FREE RADICAL SCAVENGING OR SINGLET O QUENCHING BUT ALSO A POSSIBLE ROLE OF 400 NM LIGHT ABSORPTION, A PROPERTY OF BETA-CAROTENE. Beta carotene protects patients with erythropoietic protoporphyria against severe photosensitivity reactions (burning sensation, edema, erythema, pruritus, and/or cutaneous lesions). The drug has no effect on the basic biochemical abnormality of erythropoietic protoporphyria (eg, erythrocyte, plasma, and stool concentrations of protoporphyrins are not altered by the drug). The precise mechanism by which the drug exerts photoprotection has not been established. There is some evidence that photosensitizers may act through the formation of singlet excited oxygen and/or free radicals. Since in vitro studies indicate that beta carotene can quench free radicals and singlet excited oxygen, this may be the mechanism by which the drug acts. It is unlikely that beta carotene acts simply as a filter for the wavelengths of light that induce phototoxic effects. beta-Carotene inhibits UV-B carcinogenesis. beta-Carotene is an excellent quencher of singlet oxygen, and can quench free radicals. beta-Carotene has been shown to quench singlet oxygen/free radical reactions in the skin of porphyric mice, and has been found to quench excited species formed on irradiation of mouse skin by UV-B.

Pharmacodynamics

Oral administration of beta-carotene increases the serum concentration of beta-carotene by 60% but it does not change the concentration found in the heart, liver or kidneys. In vitro studies in hepatocytes have shown that beta-carotene ameliorates oxidative stress, enhances antioxidant activity and decreases apoptosis. Other than the antioxidant activities, some other actions have been correlated to beta-carotene. It is thought to have detoxifying properties, as well as to help increase resistance to inflammation and infection and increase immune response and enhance RNA production.

Mechanism of action

Xanthophylls have antioxidant activity and react with active oxygen species, producing biologically active degradation products. They also can inhibit peroxidation of membrane phospholipids and reduce lipofuscin formation, both of which contribute to their antioxidant properties. Lutein is naturally present in the macula of the human retina. It filters out potentially phototoxic blue light and near-ultraviolet radiation from the macula. The protective effect is due in part, to the reactive oxygen species quenching ability of these carotenoids. Lutein is more stable to decomposition by pro-oxidants than are other carotenoids such as beta-carotene and lycopene. Lutein is abundant in the region surrounding the fovea, and lutein is the predominant pigment at the outermost periphery of the macula. Zeaxanthin, which is fully conjugated (lutein is not), may offer somewhat better protection than lutein against phototoxic damage caused by blue and near-ultraviolet light radiation. Lutein is one of only two carotenoids that have been identified in the human lens, may be protective against age-related increases in lens density and cataract formation. Again, the possible protection afforded by lutein may be accounted for, in part, by its reactive oxygen species scavenging abilities. Carotenoids also provide protection from cancer. One of the mechanisms of this is by increasing the expression of the protein connexin-43, thereby stimulating gap junctional communication and preventing unrestrained cell proliferation.

Pharmacodynamics

Lutein was found to be present in a concentrated area of the macula, a small area of the retina responsible for central vision. The hypothesis for the natural concentration is that lutein helps protect from oxidative stress and high-energy light. Several studies show that an increase in macula pigmentation decreases the risk for eye diseases such as Age-related Macular Degeneration (AMD).