Levapan 10%

Indications

• Helminth infections
• Strongyloides infections
• Brugia malayi infections
• Wuchereria bancrofti infections
• Adjunctive therapy in colon cancer with fluorouracil

Dosage

Children: For children aged 1 month to 9 years: Initially 1 mg/kg daily in divided doses on the first day, then increased to 3

Adults: Initially 1 mg/kg daily on the first day, then increased to 6 mg/kg daily in divided doses, with the maximum dose not exceeding 9 mg/kg per day.

Mechanism of action

Levamisole exerts its antiparasitic action by acting as an agonist at L-subtype nicotinic acetylcholine receptors in the muscles of nematodes. This results in paralysis of the worms, preventing their reproductive capabilities. As an immunomodulator, Levamisole restores depressed immune functions, enhances T-cell activation, stimulates antibody formation, and increases macrophage and neutrophil activities.

Pharmacodynamics

Levamisole's pharmacodynamics are characterized by its dual role as an anthelmintic and an immunomodulator. As an anthelmintic, it specifically targets nematodes by agonizing their nicotinic acetylcholine receptors, leading to muscle paralysis. The immunomodulatory effects include activation of natural killer (NK) cells and T-cells, enhancing the host's immune response, and improving macrophage function.

Pharmacokinetics

Levamisole is rapidly absorbed after oral administration, with peak plasma concentrations occurring within 1 to 2 hours. It is extensively metabolized in the liver, and its metabolites are excreted in urine. The elimination half-life is approximately 4 to 6 hours. Care should be taken in patients with hepatic impairment, as dose adjustments may be necessary.

Contra-indications

• Blood disorders

Adverse effects

• Arthralgia (long term use)
• Diarrhoea
• Dizziness
• Headache
• Influenza-like illness (long term use)
• Insomnia (long term use)
• Myalgia (long term use)
• Nausea
• Rash (long term use)
• Seizure (long term use)
• Taste altered (long term use)
• Vasculitis (long term use)
• Vomiting

Interactions

• Levamisole moderately decreases exposure to albendazole
• Levamisole increases exposure to ivermectin

Precautions

• Epilepsy
• Sjögren’s syndrome

Pregnancy

Embryotoxic in animal studies, avoid if possible.

Breast-feeding

No information available.

Storage

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

Formulations

• 50 mg chewable tablets

Indications

• Food preservative
• Treatment of urea cycle disorders
• Metabolic disorders involving benzoyl-CoA

Dosage

Children: Refer to the BNF for Children for specific dosing guidelines based on condition.

Adults: Refer to the BNF for specific dosing guidelines based on condition.

Mechanism of action

Benzoate acts mainly by inhibiting the growth of bacteria and fungi through its ability to lower the pH, creating an environment that is less favorable for microbial growth. It is also involved in metabolic pathways where it helps in the conjugation of toxic substances, facilitating their excretion from the body.

Pharmacodynamics

Benzoate is known for its antimicrobial properties, which are particularly effective against a wide range of fungi and bacteria. Its efficacy as a preservative is due to its ability to penetrate microbial cell membranes and disrupt their metabolic processes. Additionally, it has been observed to modulate various metabolic pathways, particularly those associated with aromatic compound degradation.

Pharmacokinetics

After ingestion, benzoate is rapidly absorbed in the gastrointestinal tract. It is metabolized primarily in the liver, where it undergoes conjugation with glycine to form hippurate, which is then excreted in the urine. The half-life of benzoate varies depending on individual metabolic rates but is generally short due to its efficient conversion and excretion.

Pregnancy

There is limited data on the use of benzoate in pregnancy. Consultation with healthcare professionals is advised before use.

Breast-feeding

Limited data is available on the excretion of benzoate in breast milk. Caution is recommended when administering to nursing mothers.

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

Indications

• Age-related macular degeneration
• Eye health supplementation
• Antioxidant support

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations.

Adults: Refer to the BNF for specific dosing recommendations.

Mechanism of action

Zeaxanthin acts as a light filter in the retina, protecting the eyes from harmful high-energy light waves like ultraviolet rays. It is believed to neutralize free radicals and reduce oxidative stress, which can contribute to various ocular diseases. Additionally, zeaxanthin is involved in the carotenoid biosynthesis pathways, including its conversion from violaxanthin and its role in various biosynthetic processes.

Pharmacodynamics

Zeaxanthin exhibits antioxidant activity, which helps protect cells from oxidative damage. It is selectively deposited in the macula of the eye, where it contributes to visual acuity and may prevent photochemical damage caused by light exposure. Its presence in the retina aids in filtering blue light and supports overall retinal health.

Pharmacokinetics

Zeaxanthin is absorbed in the gastrointestinal tract after dietary intake, with peak plasma concentrations occurring several hours post-ingestion. It is transported in the bloodstream bound to lipoproteins, and its bioavailability can vary based on dietary fat presence. The half-life of zeaxanthin in the body is not well established but is believed to be several days, as it is stored in the retina and other tissues.

Pregnancy

There is insufficient data on the safety of zeaxanthin during pregnancy. Consult a healthcare provider for advice.

Breast-feeding

Limited data is available on the excretion of zeaxanthin in human milk. Consult a healthcare provider for guidance.

Storage

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

Formulations

• Dietary supplements
• Ophthalmic preparations

Mechanism of action

The mechanism of action of levamisole as an antiparasitic agent appears to be tied to its agnositic activity towards the L-subtype nicotinic acetylcholine receptors in nematode muscles. This agonistic action reduces the capacity of the males to control their reproductive muscles and limits their ability to copulate. The mechanism of action of Levamisole as an anticancer drug in combination with fluorouracil is unknown. The effects of levamisole on the immune system are complex. The drug appears to restore depressed immune function rather than to stimulate response to above-normal levels. Levamisole can stimulate formation of antibodies to various antigens, enhance T-cell responses by stimulating T-cell activation and proliferation, potentiate monocyte and macrophage functions including phagocytosis and chemotaxis, and increase neutrophil mobility, adherence, and chemotaxis.

Pharmacodynamics

Levamisole is a synthetic imidazothiazole derivative that has been widely used in treatment of worm infestations in both humans and animals. As an anthelmintic, it probably works by targeting the nematode nicotinergic acetylcholine receptor. As an immunomodulator, it appears that Levamisole is an immunostimulant which has been shown to increase NK cells and activated T-cells in patients receiving this adjuvantly along with 5FU for Stage III colon cancer.

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).