FENAZOLE 10%

Indications

• Dry eye conditions
• Keratoconjunctivitis sicca
• Unstable tear film

Dosage

Children: Apply 3–4 times a day or when required to the eye.

Adults: Apply 3–4 times a day or when required to the eye.

Mechanism of action

Carmellose sodium acts as a viscosity-increasing agent, providing lubrication and hydration. It works by creating a gel-like consistency that mimics natural tears, thus improving moisture retention on the ocular surface. This action alleviates dryness and irritation in the eyes.

Pharmacodynamics

Carmellose sodium exhibits mucomimetic properties, which means it has the ability to mimic natural mucus in the eye. Its effectiveness in reducing symptoms of dryness is attributed to its ability to increase tear film stability and provide a protective barrier against environmental irritants. It does not have systemic effects as it is used topically.

Pharmacokinetics

Carmellose sodium is administered topically and is not absorbed systemically, making its pharmacokinetics primarily local. The onset of action is rapid, providing immediate relief for dry eye symptoms. The duration of action depends on factors such as the formulation and frequency of administration. Due to its high molecular weight, it remains on the ocular surface for an extended period, ensuring prolonged lubrication.

Adverse effects

• Transient blurred vision
• Eye irritation
• Allergic reactions

Precautions

• Consult a healthcare professional if symptoms persist
• Avoid contact with the tip of the dropper to prevent contamination

Pregnancy

Carmellose sodium is generally considered safe for use during pregnancy. However, consult a healthcare provider for personalized advice.

Breast-feeding

Carmellose sodium is not known to pose a risk during breastfeeding, but it is advisable to consult a healthcare provider.

Storage

Store at room temperature, away from direct sunlight. Keep out of reach of children.

Formulations

• Carmize 0.5% eye drops
• Carmize 1% eye drops
• Cellusan 0.5% eye drops
• Celluvisc 0.5% eye drops
• Liquivisc 0.25% eye gel
• Ocu-Lube Carmellose 0.5% eye drops
• Tearvis 0.5% eye drops

Indications

• Dry eye syndrome
• Ocular lubrication
• Gastroesophageal reflux disease (GERD)
• Topical applications (as a lubricant or protectant)

Dosage

Children: Refer to specific formulation guidelines for recommended dosages, as doses vary widely depending on the formulation and intended use.

Adults: Refer to specific formulation guidelines for recommended dosages, as doses vary widely depending on the formulation and intended use.

Mechanism of action

Carmellose works by increasing the viscosity of solutions and forming a gel-like consistency when mixed with water. This property allows it to act as a lubricant and protectant, particularly in formulations designed for ocular or gastrointestinal use. The water-binding capacity of carmellose helps to retain moisture in tissues, which can be beneficial in treating dryness.

Pharmacodynamics

The pharmacodynamic properties of carmellose are primarily related to its ability to modify the physical properties of solutions and suspensions. It does not exert specific pharmacological effects but rather enhances the bioavailability and stability of active ingredients in pharmaceutical formulations. Its hydrophilic nature allows it to hold water and improve the consistency of products, thus facilitating drug delivery and absorption.

Pharmacokinetics

Carmellose is not absorbed systemically when administered orally, as it is primarily used as an excipient. It passes through the gastrointestinal tract without significant metabolism. The elimination half-life is not applicable, as it does not enter systemic circulation. Its effects are localized to the site of application or ingestion, where it acts as a bulking agent or thickener.

Adverse effects

• Gastrointestinal discomfort
• Bloating
• Diarrhea

Precautions

• Use with caution in patients with gastrointestinal disorders
• Monitor for hypersensitivity reactions

Pregnancy

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

Breast-feeding

Carmellose is considered safe for use during breastfeeding, but it is recommended to seek advice from a healthcare professional.

Storage

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

Formulations

• Powder
• Tablet
• Capsule
• Suspension

Indications

• Acidulant in food and beverages
• Preservative in pharmaceutical formulations
• pH adjuster in various chemical preparations

Dosage

Children: Refer to product-specific guidelines for appropriate dosing based on formulation and indication.

Adults: Refer to product-specific guidelines for appropriate dosing based on formulation and indication.

Mechanism of action

Citric acid acts by chelating metal ions, which can enhance the solubility of certain compounds and improve their bioavailability. It also contributes to the acidity of the environment, which can influence enzymatic activity and metabolic pathways, particularly in the degradation of citronellol.

Pharmacodynamics

Citric acid exhibits mild pharmacological effects primarily attributed to its role in metabolic processes. It aids in the regulation of pH levels, which can impact enzymatic reactions and biochemical pathways. The acid's chelating properties may help to reduce the toxicity of certain metal ions in biological systems.

Pharmacokinetics

Citric acid is rapidly absorbed after oral administration and is metabolized in the liver. It undergoes conversion to various metabolites in the citric acid cycle, contributing to energy production. The elimination primarily occurs through urine, with minimal accumulation in the body.

Pregnancy

Citric acid is generally regarded as safe during pregnancy when used in food amounts. However, consult a healthcare provider for advice on medicinal use.

Breast-feeding

Citric acid is considered safe during breastfeeding when consumed in food amounts. For medicinal use, consult a healthcare provider.

Storage

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

Indications

• Dry skin
• Skin irritation
• Eczema
• Dermatitis
• Cosmetic applications as a moisturizer and thickening agent

Dosage

Children: Refer to specific product guidelines as dosing can vary based on formulation and intended use.

Adults: Refer to specific product guidelines as dosing can vary based on formulation and intended use.

Mechanism of action

Dimethicone works by forming a protective layer on the skin, which helps to seal in moisture and protect the skin from irritants. Its anti-foaming properties are due to its ability to reduce surface tension, allowing gas bubbles to coalesce and escape more easily, thus diminishing the formation of foam in solutions.

Pharmacodynamics

Dimethicone exhibits emollient properties, which means it can soften and soothe the skin. It acts by creating a barrier that prevents transepidermal water loss, thereby enhancing hydration. Its non-irritating nature makes it suitable for sensitive skin, and it does not clog pores, making it a preferred choice in many dermatological preparations.

Pharmacokinetics

Dimethicone is not absorbed systemically; it remains on the skin surface and does not penetrate into the deeper layers of the skin. This characteristic makes it effective as a topical agent. Because it is not metabolized or excreted by the body, its pharmacokinetic profile is primarily focused on its local effects rather than systemic absorption.

Adverse effects

• Allergic reactions
• Skin irritation
• Gastrointestinal discomfort

Precautions

• Use with caution in patients with a history of allergic reactions to silicone-based compounds
• Monitor for any signs of adverse reactions during treatment

Pregnancy

Dimethicone is generally considered safe for use during pregnancy, as it is not absorbed systemically.

Breast-feeding

Dimethicone is considered safe for use during breastfeeding, as it is not absorbed and is unlikely to affect breastfed infants.

Storage

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

Formulations

• Topical creams
• Lotions
• Ointments
• Oral suspensions

Indications

• Nutritional support in patients unable to consume food orally
• Parenteral nutrition
• Drug delivery for lipophilic medications
• Topical applications for skin conditions

Dosage

Children: Refer to specific product guidelines and clinical protocols for paediatric dosing.

Adults: Refer to specific product guidelines and clinical protocols for adult dosing.

Mechanism of action

Emulsions work by reducing the surface tension between the oil and water phases, allowing for the formation of stable droplets. This process is mediated by emulsifying agents, which can be surfactants or natural polymers that stabilize the emulsion and prevent phase separation. The absorption and bioavailability of drugs within the emulsion can be enhanced due to the increased surface area for absorption.

Pharmacodynamics

The pharmacodynamics of emulsions vary based on their composition and formulation. The presence of emulsifying agents can influence the release profile of the active ingredients, allowing for controlled or sustained release. Emulsions can also enhance the solubility of poorly water-soluble drugs, improving their therapeutic effects and minimizing side effects related to high concentrations of active ingredients.

Pharmacokinetics

The pharmacokinetics of emulsions depend on their route of administration and the specific properties of the drug contained within the emulsion. After administration, emulsions can be rapidly absorbed due to their small droplet size, leading to quicker onset of action. The distribution, metabolism, and excretion of the drug will follow the pharmacokinetic principles applicable to the active ingredients, influenced by their solubility and the emulsion's formulation.

Pregnancy

The safety of emulsions during pregnancy depends on the specific type and formulation. Consult relevant guidelines and specific product information.

Breast-feeding

Emulsions may be used while breastfeeding, but specific product information should be consulted to ensure safety.

Storage

Store at room temperature, away from light and moisture. Specific formulations may have unique storage requirements.

Indications

• Intestinal nematodes
• Cestodes
• Helminth infections in veterinary practice

Dosage

Children: Refer to the BNF for Children for appropriate dosing recommendations for paediatric patients.

Adults: Refer to the BNF for specific dosing guidelines, as adult doses may vary depending on the type of infection being treated.

Mechanism of action

Fenbendazole exerts its antiparasitic effects by binding to beta-tubulin in parasites, leading to microtubule destabilization and inhibiting tubulin polymerization. This process disrupts cellular functions, including glucose uptake and energy management, particularly in the anterior intestine, where it is most effective due to its poor absorption following oral administration.

Pharmacodynamics

The primary pharmacodynamic action of fenbendazole involves its ability to alter the structure and function of microtubules in parasitic cells. By inhibiting the polymerization of tubulin, fenbendazole interferes with various cellular processes, including mitosis and the transport of secretory vesicles. This ultimately results in the death of the parasites, as they are unable to maintain essential cellular functions.

Pharmacokinetics

Fenbendazole has low oral bioavailability due to poor absorption from the gastrointestinal tract. It undergoes hepatic metabolism and is excreted primarily in the faeces. The duration of action is affected by the persistence of the drug in the intestinal lumen, where it maintains its anthelmintic effects.

Pregnancy

Fenbendazole is not recommended during pregnancy due to potential risks to the developing fetus.

Breast-feeding

It is not known whether fenbendazole is excreted in human milk. Caution is advised when administering to nursing mothers.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• {'formulation': 'Powder for oral suspension', 'strength': 'Various strengths available'}
• {'formulation': 'Tablets', 'strength': 'Various strengths available'}

Indications

• Wound healing
• Skin ulceration
• Burns
• Psoriasis
• Dermatitis

Dosage

Children: Refer to the BNF for Children for appropriate dosing information based on the child's age and condition.

Adults: Refer to the BNF for specific formulations and dosing guidelines, as dosages may vary based on the condition being treated and the formulation used.

Mechanism of action

While there is no well-controlled data to formally substantiate the method of action, ongoing studies suggest that allantoin may induce a histological wound healing profile in animal models, leading to improved reestablishment of normal skin. This includes increased vasodilation, inflammatory cell presence, angiogenesis, fibroblast proliferation, and collagen deposition in treated wounds compared to untreated ones.

Pharmacodynamics

There is limited controlled data regarding the pharmacodynamic properties of allantoin. However, studies indicate that allantoin may possess moisturizing and keratolytic effects, increasing the extracellular matrix's water content and enhancing the desquamation of dead skin cells. These activities can promote cell proliferation and facilitate wound healing.

Pharmacokinetics

Specific pharmacokinetic data for allantoin in humans is limited. However, it is known to be applied topically, which suggests local absorption at the site of application. Systemic absorption is considered minimal due to its low molecular weight and hydrophilicity.

Pregnancy

There is limited data on the safety of allantoin in pregnancy. It is advisable to consult a healthcare professional before use.

Breast-feeding

Allantoin is generally considered safe during breastfeeding, but caution is recommended. Consult a healthcare professional before use.

Storage

Store at room temperature, away from direct sunlight and moisture. Keep out of reach of children.

Formulations

• Topical cream
• Gel
• Ointment

Indications

• Allergic conditions
• Autoimmune diseases
• Asthma and chronic obstructive pulmonary disease (COPD)
• Certain cancers (e.g., leukemia, lymphoma)
• Skin conditions (e.g., dermatitis)
• Inflammatory bowel disease
• Multiple sclerosis exacerbations
• Severe infections requiring immunosuppression

Dosage

Children: Refer to BNF for Children for specific dosing; doses vary significantly based on the child's age, weight, and condition being treated.

Adults: Refer to BNF for specific dosing; typically, initial doses range from 4 to 48 mg depending on the severity of the condition.

Mechanism of action

Methylprednisolone exerts its effects by binding to glucocorticoid receptors, leading to the modulation of gene expression. This interaction influences the transcription of anti-inflammatory proteins while suppressing the expression of pro-inflammatory genes, ultimately resulting in reduced inflammation and immune response.

Pharmacodynamics

The pharmacodynamic effects of methylprednisolone are characterized by its ability to decrease inflammation, suppress the immune response, and affect carbohydrate metabolism. Therapeutic doses lead to various systemic effects, including modification of leukocyte distribution and inhibition of cytokine production.

Pharmacokinetics

Methylprednisolone is well absorbed after oral administration, with a bioavailability of approximately 50%. It has a volume of distribution that reflects extensive tissue binding. The drug is metabolized primarily in the liver through conjugation and reduction, and its metabolites are excreted in urine. The half-life varies based on the route of administration but is generally around 18 to 36 hours.

Adverse effects

• Increased blood pressure
• Hyperglycemia
• Weight gain
• Mood changes
• Insomnia
• Gastrointestinal disturbances
• Increased susceptibility to infections

Interactions

• methylphenidate+apraclonidine: Severe (decreases effects)
• methylthioninium chloride+bupropion: Severe (increases risk of severe hypertension)
• methylphenidate+linezolid: Severe (increases risk of elevated blood pressure)
• rasagiline+methylphenidate: Severe (increases risk of a hypertensive crisis)
• mao-inhibitors+methylphenidate: Severe (increases risk of a hypertensive crisis)
• dronedarone+methylprednisolone: Moderate (increases exposure)
• miconazole+methylprednisolone: Moderate (increases concentration)
• antifungals, azoles+methylprednisolone: Moderate (increases exposure)
• crizotinib+methylprednisolone: Moderate (increases exposure)

Precautions

• Use with caution in patients with hypertension
• Monitor blood glucose levels in diabetic patients
• Consider potential for infection risk due to immunosuppression
• Evaluate for psychiatric effects in susceptible individuals

Pregnancy

Corticosteroids may be used during pregnancy if the potential benefit justifies the risk to the fetus. Careful monitoring is advised.

Breast-feeding

Corticosteroids are excreted in breast milk; caution is advised. Monitor the infant for potential effects.

Storage

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

Formulations

• Tablets
• Injectable solutions
• Topical preparations

Mechanism of action

Methylsulphate functions as a methylating agent, transferring a methyl group to nucleophiles. This process involves the formation of a sulfonium ion, which is highly reactive and can readily react with nucleophilic sites on various substrates, leading to methylation reactions.

Pharmacodynamics

The pharmacodynamics of methylsulphate is primarily related to its role as a methylating agent in biochemical reactions. It can alter the structure and function of biological molecules, potentially affecting cellular processes and signaling pathways. However, detailed pharmacodynamic studies specific to therapeutic use are limited.

Pharmacokinetics

There is limited information on the pharmacokinetics of methylsulphate, given its typical use as a reagent in laboratory settings rather than a clinical drug. When used in chemical reactions, its reactivity and transformation into other compounds would dictate its pharmacokinetic profile, which could vary significantly based on the specific context of use.

Pregnancy

There is limited data on the use of methylsulphate in pregnancy. Consult relevant guidelines.

Breast-feeding

Data on the excretion of methylsulphate in human milk is not available. Caution is advised.

Storage

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

Indications

• Preservative in cosmetics
• Preservative in pharmaceuticals
• Preservative in food products

Dosage

Children: Refer to specific product guidelines as dosing varies based on formulation and concentration used.

Adults: Refer to specific product guidelines as dosing varies based on formulation and concentration used.

Mechanism of action

Parabens work by inhibiting the growth of microorganisms through their ability to disrupt the cellular processes of bacteria and fungi. They penetrate the microbial cell membrane and disrupt enzyme and protein functions, leading to cell death. Parabens are known to have low toxicity and are metabolized by the body, subsequently being excreted in urine.

Pharmacodynamics

Parabens demonstrate broad-spectrum antimicrobial activity, making them effective preservatives in various formulations. Their efficacy is influenced by factors such as concentration, pH, and the presence of other ingredients in the formulation. Due to their structural similarity to estrogen, there has been concern regarding their potential endocrine-disrupting effects, although the clinical significance of this is still debated.

Pharmacokinetics

Parabens are readily absorbed through the skin and gastrointestinal tract. Once absorbed, they are rapidly metabolized primarily in the liver. They undergo hydrolysis to form para-hydroxybenzoic acid, which is then conjugated with glucuronic acid and excreted in urine. The half-life of parabens in the human body is relatively short, and they are eliminated rapidly.

Adverse effects

• Allergic reactions, such as skin rashes
• Irritation at the site of application
• Endocrine disruption (in high concentrations)

Precautions

• Use with caution in individuals with known sensitivities or allergies to parabens
• Consider potential endocrine effects with prolonged exposure

Pregnancy

Parabens are generally considered safe in cosmetics and personal care products during pregnancy, although caution is advised due to potential endocrine disruption.

Breast-feeding

Parabens are considered safe in breastfeeding, but it is recommended to use products with minimal or no parabens when possible.

Storage

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

Formulations

• Topical creams
• Lotions
• Shampoos
• Conditioners
• Makeup products
• Pharmaceutical preparations

Indications

• Emulsifying agent in drug formulations
• Stabilizer for parenteral preparations
• Solubilizer for hydrophobic drug compounds
• Ingredient in topical formulations

Dosage

Children: Refer to specific product guidelines, as dosing varies based on formulation and intended use.

Adults: Refer to specific product guidelines, as dosing varies based on formulation and intended use.

Mechanism of action

Polysorbate functions primarily as an emulsifying agent. It reduces the surface tension between immiscible liquids, allowing them to mix more easily. This property is particularly useful in stabilizing emulsions and suspensions, facilitating the delivery of active pharmaceutical ingredients in various formulations.

Pharmacodynamics

Polysorbate does not exert pharmacological effects in the traditional sense, as it does not bind to specific receptors to elicit a physiological response. Instead, it plays a crucial role in modifying the physical properties of drug formulations, thereby enhancing drug delivery and absorption. Its ability to solubilize drugs enhances their bioavailability, particularly for poorly soluble compounds.

Pharmacokinetics

Polysorbate is generally considered to be non-toxic and is not absorbed to a significant extent when administered orally. It is metabolized by the liver and excreted primarily through the gastrointestinal tract. The pharmacokinetic profile may vary depending on the route of administration and the specific formulation in which it is used.

Adverse effects

• Allergic reactions
• Skin irritation
• Gastrointestinal disturbances

Precautions

• Use cautiously in patients with known allergies to polysorbates or related compounds
• Monitor for allergic reactions in susceptible individuals

Pregnancy

Polysorbate is generally considered safe for use during pregnancy, but consult with a healthcare provider for specific cases.

Breast-feeding

Polysorbate is considered safe during breastfeeding, but consult with a healthcare provider for individual advice.

Storage

Store at room temperature, away from direct sunlight and moisture.

Formulations

• Polysorbate 20
• Polysorbate 80

Indications

• Hyperthyroidism
• Graves' disease
• Thyroid storm

Dosage

Children: Refer to the BNF

Adults: The usual initial dose of propylthiouracil in adults is 300 mg per day, divided into 3 doses. The maintenance dose is typically 100-150 mg per day, adjusted based on thyroid function tests.

Mechanism of action

Propylthiouracil acts by inhibiting the enzyme thyroid peroxidase, which is involved in the iodination of tyrosine residues in thyroglobulin, a precursor of thyroid hormones. By blocking this enzyme, PTU reduces the production of thyroxine (T4) and triiodothyronine (T3), leading to decreased thyroid hormone levels in circulation. Additionally, PTU inhibits the conversion of T4 to T3 in peripheral tissues, further contributing to its antithyroid effects.

Pharmacodynamics

The pharmacodynamic effects of propylthiouracil are primarily centered around its ability to lower thyroid hormone levels, which helps alleviate symptoms of hyperthyroidism such as increased heart rate, weight loss, and anxiety. The onset of action can vary, but therapeutic effects may be observed within several weeks of initiation. Monitoring thyroid function tests is essential to assess the efficacy and adjust dosing as needed.

Pharmacokinetics

Propylthiouracil is well absorbed from the gastrointestinal tract, though its bioavailability can be affected by factors such as food intake. The drug is extensively metabolized in the liver, and its elimination half-life averages around 1-2 hours. Most of the drug is excreted in urine as metabolites. It is important to note that due to its rapid metabolism, multiple daily doses may be required to maintain therapeutic levels.

Interactions

• propylthiouracil+metyrapone: Severe (decreases effects)

Indications

• Thickening agent in food products
• Stabilizer in pharmaceutical formulations
• Emulsifier in cosmetic products
• Dietary fiber supplement

Dosage

Children: Dosage should be determined based on specific formulations and medical advice. Refer to the BNF for Children for detailed guidance.

Adults: Dosage depends on the specific formulation and purpose. Refer to product-specific guidelines or consult the BNF.

Mechanism of action

Xanthan gum works by forming a viscous gel in the presence of water. This gelling property is due to its unique molecular structure, which consists of a repeating unit of glucose, mannose, and glucuronic acid. When hydrated, xanthan gum can create a three-dimensional network that traps water, thus increasing the viscosity of the solution. This ability to enhance the texture and stability of various formulations is what makes xanthan gum a valuable ingredient in many products.

Pharmacodynamics

The pharmacodynamic properties of xanthan gum are primarily related to its thickening and stabilizing effects. It does not possess any pharmacological activity in the traditional sense, as it is not absorbed into the systemic circulation. Instead, its primary function is to modify the rheological properties of the formulations it is included in, affecting how they flow and interact with other ingredients.

Pharmacokinetics

Xanthan gum is not metabolized by the body and is considered safe for consumption. It is largely excreted unchanged in the feces. The gastrointestinal absorption of xanthan gum is minimal, which means it does not exert systemic effects. Upon ingestion, it may contribute to dietary fiber intake, promoting digestive health. Its viscosity can also influence gastrointestinal transit time, potentially providing a feeling of fullness.

Adverse effects

• Gastrointestinal discomfort
• Flatulence
• Diarrhea
• Bloating
• Allergic reactions (rare)

Precautions

• Use with caution in individuals with gastrointestinal disorders
• Monitor for allergic reactions in sensitive individuals

Pregnancy

Xanthan gum is generally considered safe for use during pregnancy as it is a food additive and not absorbed in significant amounts.

Breast-feeding

Xanthan gum is considered safe during breastfeeding as it is not absorbed systemically.

Storage

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

Formulations

• Powder
• Gel
• Liquid
• Capsules

Mechanism of action

Due to its poor absorption by oral administration, fenbendazole is particularly effective for targeting intestinal parasites. It exerts its antiparasitic effects primarily in the anterior intestine by depolymerizing microtubules, inhibiting intestinal secretory vesicle transport. When fenbendazole binds to beta-tubulin in parasites, it causes microtubule destabilization and hinders tubulin polymerization. This destabilization disrupts cellular function, such as glucose uptake, and thus affects the energy management of parasites.

Mechanism of action

There is no well controlled data that can formally substantiate the method of action. However, ongoing studies suggest that there may exist a histological wound healing profile induced by allantoin in rats that leads to the amelioration and fastening of the reestablishment of normal skin. This facilitation of wound healing is supported by observations that wounds inflicted to rat subjects to which topical allantoin preparations were applied histologically demonstrated increased vasodilation, presence of inflammatory exudates, number of inflammatory cells, angiogenesis, fibroblast proliferation, and increased collagen deposition when compared to rat subjects with wounds that did not receive any allantoin administration.

Pharmacodynamics

There is no well controlled and appropriate data that can formally substantiate the pharmacodynamic properties of allantoin. Nevertheless, ongoing studies suggest that allantoin possesses moisturizing and keratolytic effects, as well as abilities to increase the water content of the extracellular matrix and enhance the desquamation of upper layers of dead skin cells, all of which are activities that can promote cell proliferation and facilitate wound healing.