LEVOZIN

Indications

• Pruritus
• Eczema
• Acne
• Rosacea

Dosage

Children: For children aged 12-17 years, apply up to 3 grams 3-4 times a day, ensuring coverage is less than 10% of body surface area.

Adults: Apply thinly to the affected area 1-2 times a day. Maximum application should cover less than 10% of body surface area, with a total daily maximum of 12 grams.

Mechanism of action

Levomenthol primarily activates the cold-sensitive TRPM8 receptors in the skin. This stimulation leads to a feeling of coolness by inhibiting calcium ion currents in neuronal membranes. Additionally, menthol may exhibit analgesic properties through kappa-opioid receptor agonism, further contributing to its pain-relieving effects.

Pharmacodynamics

Levomenthol is a covalent organic compound that can be synthesized or extracted from peppermint and other mint oils. It induces a cooling sensation when applied topically, inhaled, or ingested, by stimulating cold-sensitive receptors located in the skin. Notably, this effect occurs without a decrease in actual skin temperature, making it useful in topical formulations for managing discomfort.

Pharmacokinetics

Levomenthol is absorbed through the skin upon topical application. Its effects are localized, and it does not significantly enter systemic circulation when used as directed. The onset of action is typically rapid, providing immediate symptomatic relief from conditions like itching and irritation.

Contra-indications

• Severe heart disease
• Severe hepatic impairment
• Glaucoma
• Urinary retention
• History of mania or arrhythmias

Adverse effects

• Drowsiness
• Dizziness
• Headache
• Nausea
• Vomiting
• Dry mouth
• Dry eyes
• Diarrhea
• Constipation
• Skin reactions
• Altered taste
• Blurred vision
• Suicidal behaviors

Interactions

• Tricyclic antidepressants
• Other central nervous system depressants

Precautions

• Avoid application to large areas of the skin
• Use caution in patients with a history of psychiatric disorders
• Caution advised for driving and skilled tasks due to potential somnolence or dizziness

Pregnancy

Manufacturer advises use only if potential benefit outweighs risk.

Breast-feeding

Manufacturer advises use only if potential benefit outweighs risk.

Storage

Store in a cool, dry place, protected from light.

Formulations

• AquaSoothe 1% cream (Menthol 10 mg per 1 gram)
• AquaSoothe 2% cream (Menthol 20 mg per 1 gram)
• Arjun 0.5% cream (Menthol 5 mg per 1 gram)
• Arjun 1% cream (Menthol 10 mg per 1 gram)
• Dermacool 0.5% cream (Menthol 5 mg per 1 gram)
• Dermacool 1% cream (Menthol 10 mg per 1 gram)
• Menthoderm 0.5% cream (Menthol 5 mg per 1 gram)
• Menthoderm 1% cream (Menthol 10 mg per 1 gram)
• Menthoderm 2% cream (Menthol 20 mg per 1 gram)
• Menthoderm 5% cream (Menthol 50 mg per 1 gram)

Indications

• Infections (topical treatment)
• Wound care (as an antiseptic)
• Ear infections (as an ear drop solution)
• Acid-base balance in metabolic acidosis

Dosage

Children: Refer to established guidelines as dosage may vary based on the formulation and indication.

Adults: Refer to established guidelines as dosage may vary based on the formulation and indication.

Mechanism of action

Acetic acid exerts its effects primarily through its ability to lower pH levels, creating an acidic environment which is inhospitable to many pathogens. It can disrupt the integrity of microbial cell membranes, leading to cell lysis and death. Additionally, acetic acid can promote the healing of wounds and enhance the absorption of certain medications when used as a solvent.

Pharmacodynamics

The pharmacodynamics of acetic acid involve its interaction with biological systems, leading to changes in cellular functions. Its acidic nature helps in the denaturation of proteins and disruption of microbial metabolism. This contributes to its antibacterial and antifungal activities, making it effective against a range of pathogens.

Pharmacokinetics

Acetic acid is rapidly absorbed in the gastrointestinal tract when ingested. It is metabolized primarily in the liver, converting to acetyl CoA and subsequently entering various metabolic pathways including the citric acid cycle. The elimination half-life varies but is generally short, with excretion occurring mainly via urine. When applied topically, absorption is minimal, and local effects are predominant.

Pregnancy

The safety of acetic acid during pregnancy has not been established. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

There is no specific information available regarding the use of acetic acid during breastfeeding. Caution is advised.

Storage

Store in a cool, dry place away from direct sunlight. Keep tightly closed in a well-ventilated area.

Indications

• Enhancement of taste in food and beverages
• Improvement of palatability in nutritional products
• Masking undesirable flavors in medications

Dosage

Children: There is no specific pediatric dosage for flavor agents as they are used as needed to improve the taste of food and beverages.

Adults: There is no specific dosage for flavor agents as they are used as needed to achieve the desired taste and aroma in food and beverages.

Mechanism of action

Flavor compounds interact with taste receptors on the tongue, stimulating the sensory neurons responsible for taste perception. This interaction influences the overall flavor profile of food and beverages, enhancing the eating experience. Some flavors may also have a psychological effect, stimulating appetite or evoking pleasant memories associated with certain tastes.

Pharmacodynamics

While flavor agents are primarily used for sensory enhancement in food, their pharmacodynamic effects are minimal as they are not designed to elicit a pharmacological response. However, certain flavors may influence digestion and metabolism indirectly by enhancing saliva production or affecting gut motility. The enjoyment of flavored products can also lead to increased food intake and satisfaction.

Pharmacokinetics

Flavour compounds are typically ingested and metabolized by the body. Their absorption rates can vary depending on their chemical structure and formulation. Once ingested, they may be rapidly metabolized in the liver and other tissues, with excretion primarily via urine. The specific pharmacokinetic profiles of flavor agents can vary significantly based on their source and chemical properties.

Pregnancy

Flavours are generally considered safe for use during pregnancy, but specific assessments should be made based on the type of flavouring agent.

Breast-feeding

Most flavouring agents are deemed safe during breastfeeding, although it's advisable to consult healthcare professionals regarding specific ingredients.

Storage

Store in a cool, dry place away from direct sunlight and heat sources. Ensure that the container is tightly sealed to prevent contamination.

Indications

• Nutritional supplementation
• Support for digestive health
• Antioxidant support
• General wellness enhancement

Dosage

Children: Refer to the product-specific guidelines or consult with a healthcare professional for appropriate dosing.

Adults: Refer to the product-specific guidelines or consult with a healthcare professional for appropriate dosing.

Mechanism of action

The specific mechanism of action for Frutti may vary depending on its formulation. Generally, the ingredients in fruit-based supplements provide antioxidants, vitamins, and dietary fiber that can support various biological functions, including enhancing metabolic processes, reducing oxidative stress, and promoting gut health.

Pharmacodynamics

Frutti's pharmacodynamics is largely influenced by its constituent fruits and nutrients. Antioxidants present in fruits can neutralize free radicals, reducing oxidative stress in the body. Additionally, dietary fibers can enhance gastrointestinal motility, improve digestion, and support the growth of beneficial gut microbiota.

Pharmacokinetics

The pharmacokinetics of Frutti depend on its specific ingredients. Typically, vitamins and minerals are absorbed in the gastrointestinal tract, with the extent and rate of absorption varying based on factors such as the presence of other nutrients, the formulation of the supplement, and individual patient factors, including age and health status. Metabolism often occurs in the liver, while excretion typically happens via urine and feces.

Pregnancy

Consult a healthcare professional before use. Safety during pregnancy has not been established.

Breast-feeding

Consult a healthcare professional before use. Safety during breastfeeding has not been established.

Storage

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

Indications

• Topical treatment of localized infections
• Antiseptic for skin and mucous membrane applications
• Astringent in certain dermatological conditions

Dosage

Children: Refer to professional resources for specific dosing information, as it can vary based on formulation and condition treated.

Adults: Refer to professional resources for specific dosing information, as it can vary based on formulation and condition treated.

Mechanism of action

Glacial acetic acid exerts its effects primarily through its acidic properties, leading to protein denaturation and cell lysis in microbial cells. This action disrupts cellular integrity, promoting the death of bacteria and fungi. Additionally, it can alter the pH of tissues, which may contribute to its antiseptic effects.

Pharmacodynamics

The pharmacodynamic effects of glacial acetic acid are largely attributed to its ability to lower the pH in the local environment, which can inhibit the growth of certain pathogens. Its astringent properties help to reduce secretions and promote tissue contraction, which can be beneficial in managing conditions that involve inflammation or excessive exudation.

Pharmacokinetics

Glacial acetic acid is absorbed through the skin and mucous membranes when applied topically. Once absorbed, it can be metabolized by the liver, with elimination primarily occurring through urine. The exact pharmacokinetic parameters can vary based on the route of administration and the formulation used, but detailed data on half-life and volume of distribution are not well-characterized in standard references.

Pregnancy

Glacial acetic acid should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It is classified as a category C drug.

Breast-feeding

It is not known whether glacial acetic acid is excreted in human milk. Caution should be exercised when administering to nursing mothers.

Storage

Store in a tightly closed container, in a cool, dry place away from incompatible substances.

Indications

• Constipation
• Preparation for surgical or diagnostic procedures involving the rectum
• Decreasing intraocular pressure in certain ocular conditions

Dosage

Children: For children aged 2 to 6 years, 2 g to 5 g of glycerin may be used as a suppository. Children aged 6 to 12 years may use 5 g to 10 g as needed. For specific pediatric dosing, please refer to the BNF for Children.

Adults: For rectal use, 4 g to 10 g of glycerin may be administered as a suppository as needed.

Mechanism of action

When administered rectally, glycerin draws water from the tissues into the feces due to its hygroscopic action, which reflexively stimulates bowel evacuation. Additionally, glycerin creates an osmotic gradient that leads to a decrease in intraocular pressure by facilitating fluid movement from the aqueous and vitreous humors into the bloodstream.

Pharmacodynamics

Glycerin is classified as an osmotic laxative, which acts to retain water in the fecal matter, softening stools and making them easier to pass. Its local irritant effects also contribute to its laxative properties. Glycerin suppositories typically produce a bowel movement within 15 to 30 minutes of administration.

Pharmacokinetics

Glycerin is readily absorbed from the gastrointestinal tract when taken orally and is metabolized primarily in the liver. It is distributed widely throughout the body, with excretion occurring primarily via the kidneys. The onset of action for glycerin when used as a laxative is relatively quick, particularly when used rectally.

Contra-indications

• Severe dehydration
• Severe renal impairment
• Intestinal obstruction
• Appendicitis

Adverse effects

• Abdominal cramps
• Diarrhea
• Nausea
• Vomiting
• Electrolyte imbalance

Interactions

• May enhance the effects of other laxatives
• Caution with concurrent use of diuretics due to potential electrolyte imbalance

Precautions

• Use with caution in patients with renal impairment
• Monitor electrolytes in patients with prolonged use
• Not recommended for long-term use

Pregnancy

Glycerin is generally considered safe during pregnancy but should be used under medical advice.

Breast-feeding

Glycerin is excreted in breast milk in small amounts and is considered safe for use while breastfeeding.

Storage

Store at room temperature, away from moisture and heat.

Formulations

• Glycerin suppositories
• Glycerin oral solution

Indications

• Dry eye syndrome
• Osteoarthritis
• Joint lubrication
• Surgical adjunct in ophthalmic procedures

Dosage

Children: Refer to specific product information and clinical guidelines for dosing recommendations based on the route of administration and indication.

Adults: Refer to specific product information and clinical guidelines for dosing recommendations based on the route of administration and indication.

Mechanism of action

Sodium hyaluronate works by mimicking the natural hyaluronic acid present in joints and tissues. It acts as a lubricant and shock absorber, reducing friction between cartilage surfaces in joints. In the eye, it helps to maintain moisture and protect the cornea, enhancing comfort and promoting healing.

Pharmacodynamics

The pharmacodynamic effects of sodium hyaluronate are primarily related to its viscoelastic properties. It provides lubrication, reduces pain, and helps in the maintenance of joint function. In the eye, it protects against dryness and irritation, facilitating ocular surface healing. Its ability to bind water also contributes to its effectiveness in maintaining hydration in tissues.

Pharmacokinetics

Sodium hyaluronate is administered topically or via injection, depending on the indication. Following injection into the joint, it is gradually absorbed and metabolized by hyaluronidase, an enzyme that breaks down hyaluronic acid. The half-life can vary based on the site of administration and the formulation used. Systemic absorption is minimal when used as an eye drop, with most of the drug remaining in the ocular surface.

Pregnancy

The safety of Hyflo during pregnancy has not been established. It is advised to use caution and consult a healthcare provider before use.

Breast-feeding

It is not known whether Hyflo is excreted in human milk. Caution should be exercised when administering to breastfeeding women.

Storage

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

Indications

• Allergic rhinitis
• Chronic idiopathic urticaria

Dosage

Children: For children aged 6 to 12 years, the usual dose is 2.5 mg once daily. For children aged 12 years and older, the usual dose is 5 mg once daily.

Adults: The usual dose is 5 mg once daily.

Mechanism of action

Levocetirizine selectively inhibits histamine H1 receptors. This action prevents histamine from activating this receptor and causing effects like smooth muscle contraction, increased permeability of vascular endothelium, histidine uptake in basophils, stimulation of cough receptors, and stimulation of flare responses in the nervous system.

Pharmacodynamics

Levocetirizine is a second-generation histamine H1 antagonist used to treat various allergic symptoms. It has a long duration of action as it is generally taken once daily, and a wide therapeutic window as animal studies show the maximal nonlethal dose is over 100 times a normal dose. Patients are cautioned to avoid tasks that require complete alertness and to use caution in those with factors predisposing to urinary retention.

Pharmacokinetics

Levocetirizine is well absorbed from the gastrointestinal tract, with peak plasma concentrations occurring approximately 0.9 hours after oral administration. It has a volume of distribution of about 0.4 L/kg and is approximately 90% protein-bound. The elimination half-life is about 8 hours, and it is primarily excreted unchanged in the urine. Renal impairment may necessitate dosage adjustments.

Adverse effects

• Drowsiness
• Dry mouth
• Fatigue
• Headache
• Gastrointestinal disturbances

Precautions

• Use caution in patients with a history of urinary retention
• Patients should be advised to avoid tasks requiring full alertness

Pregnancy

The safety of levocetirizine in pregnancy has not been established. It should only be used if clearly needed.

Breast-feeding

Levocetirizine is excreted in breast milk. Caution is advised when administered to nursing women.

Storage

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

Formulations

• Tablets
• Oral solution

Indications

• Preservative in pharmaceuticals
• Preservative in cosmetics
• Food preservative

Dosage

Children: Refer to specific product guidelines for concentrations and usage recommendations, as there are no standardized dosing regimens for methylparaben due to its use primarily as a preservative.

Adults: Refer to specific product guidelines for concentrations and usage recommendations, as there are no standardized dosing regimens for methylparaben due to its use primarily as a preservative.

Mechanism of action

Methylparaben functions as an antimicrobial agent by disrupting the cell membrane of bacteria and fungi, leading to cell lysis and death. It exerts its effects by inhibiting the enzyme activity necessary for microbial metabolism, which ultimately prevents the growth of these microorganisms.

Pharmacodynamics

The pharmacodynamics of methylparaben involve its ability to inhibit the growth of a wide range of bacteria and fungi. It is typically effective against gram-positive bacteria and some yeast species. The compound is often used in combination with other preservatives to enhance its antimicrobial efficacy and broaden its spectrum of activity.

Pharmacokinetics

Methylparaben is rapidly absorbed through the skin and mucous membranes, with metabolism primarily occurring in the liver. It is conjugated to form glucuronide and sulfate metabolites, which are then excreted in the urine. The compound has a relatively short half-life, and its systemic exposure is low when used in topical applications.

Adverse effects

• Allergic reactions including rash, itching, and swelling
• Contact dermatitis
• Irritation at the site of application

Precautions

• Use with caution in patients with known allergies to parabens
• Should not be applied to broken or inflamed skin

Pregnancy

Limited data available; use only if clearly needed and benefits outweigh risks.

Breast-feeding

Limited data available; consult healthcare provider before use.

Storage

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

Formulations

• Topical creams
• Lotions
• Ointments
• Cosmetic products

Indications

• Preservative in pharmaceuticals
• Preservative in cosmetics
• Food additive for preservation

Dosage

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

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

Mechanism of action

Parahydroxybenzoate acts as a competitive inhibitor of the enzyme para-aminobenzoate (PABA) synthetase, which is involved in the synthesis of folate in microorganisms. This inhibition leads to the disruption of folate metabolism, essential for nucleic acid synthesis in bacteria and fungi. Additionally, parahydroxybenzoate can disrupt cellular membrane integrity in microbes, contributing to its antimicrobial effects.

Pharmacodynamics

Parahydroxybenzoate exhibits antimicrobial activity primarily against a range of bacteria and fungi. Its effectiveness is influenced by concentration, pH, and the presence of other substances. The compound is well-absorbed and has a relatively low toxicity profile, making it suitable for use in various formulations. However, some individuals may experience allergic reactions or sensitivities to parabens, leading to concerns about their widespread use.

Pharmacokinetics

Parahydroxybenzoate is rapidly absorbed after topical application or ingestion and is metabolized in the liver. It undergoes conjugation to form parahydroxybenzoate esters, which are then excreted primarily through urine. The elimination half-life and specific pharmacokinetic parameters can vary based on the route of administration and individual patient factors.

Pregnancy

Safety in pregnancy has not been established. Use only if the potential benefits justify the potential risks to the fetus.

Breast-feeding

It is not known whether parahydroxybenzoate is excreted in human milk. Caution should be exercised when administered to a nursing woman.

Storage

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

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)

Dosage

Children: Refer to specific drug formulations and product labels as purified substances can vary widely in their use and dosing.

Adults: Refer to specific drug formulations and product labels as purified substances can vary widely in their use and dosing.

Mechanism of action

The mechanism of action for purified compounds varies widely depending on the specific substance. Generally, purified drugs exert their effects by interacting with specific biological targets, such as receptors, enzymes, or ion channels, leading to a desired therapeutic effect. This interaction can involve binding to receptors to activate or inhibit signaling pathways, modulating enzymatic activity, or altering physiological processes.

Pharmacodynamics

Pharmacodynamics describes the effects of a drug on the body and the relationship between drug concentration and effect. For purified drugs, this can involve dose-response relationships and the time course of their action. The purified form often enhances potency and reduces variability in response among patients, which can lead to more predictable therapeutic outcomes. The overall effect is determined by the drug's affinity for its target, the efficacy of the drug-receptor interaction, and the downstream signaling pathways activated as a result of this interaction.

Pharmacokinetics

Pharmacokinetics involves the absorption, distribution, metabolism, and excretion (ADME) of a drug. For purified substances, absorption can be more efficient due to the absence of impurities that may affect solubility or stability. Distribution may also be enhanced, leading to higher bioavailability. Metabolism can be influenced by the structure of the purified compound, as it may be metabolized more readily by liver enzymes. Excretion typically occurs through the kidneys or liver, depending on the molecular characteristics of the purified drug.

Pregnancy

Consult with a healthcare professional, as the safety of purified forms of medications during pregnancy may vary depending on the specific substance.

Breast-feeding

Consult with a healthcare professional, as the safety of purified forms of medications during breastfeeding may vary depending on the specific substance.

Storage

Store in a cool, dry place, away from light and moisture, and keep out of reach of children.

Indications

• Sweetening agent in food and beverages
• Ingredient in pharmaceutical formulations
• Source of quick energy

Dosage

Children: Refer to specific formulations and clinical guidelines for dosing, as sucrose does not have a standardized dosage. Typically used as needed for sweetening.

Adults: Refer to specific formulations and clinical guidelines for dosing, as sucrose does not have a standardized dosage. Typically used as needed for sweetening.

Mechanism of action

Sucrose is metabolized in the body to glucose and fructose, which are then used as energy sources. It does not have a specific pharmacological mechanism of action but contributes to energy metabolism via the glycolytic and citric acid pathways.

Pharmacodynamics

Upon ingestion, sucrose is hydrolyzed by the enzyme sucrase into its constituent monosaccharides, glucose and fructose. These monosaccharides are absorbed in the small intestine and enter the bloodstream, leading to a rise in blood glucose levels. This process provides a quick source of energy for cellular functions.

Pharmacokinetics

Sucrose is rapidly absorbed in the gastrointestinal tract after hydrolysis. Its absorption depends on the presence of sucrase in the intestine. Once in the bloodstream, glucose can be utilized by cells or stored as glycogen in the liver and muscles. The elimination half-life of sucrose itself is not well-defined as it is quickly broken down and utilized.

Pregnancy

Sucrose is generally regarded as safe during pregnancy when consumed in moderation as part of a balanced diet.

Breast-feeding

Sucrose is considered safe during breastfeeding when consumed in normal dietary amounts.

Storage

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

Formulations

• Oral solution
• Granules
• Tablets

Indications

• Constipation
• Digestive health
• Weight management
• Improved gut microbiota

Dosage

Children: Refer to specific product instructions, as dosage may vary based on formulation and purpose.

Adults: Refer to specific product instructions, as dosage may vary based on formulation and purpose.

Mechanism of action

Supercel works by promoting the absorption of water and forming a gel-like substance in the gastrointestinal tract. This mechanism helps to increase stool bulk and reduce constipation. Additionally, the fibers in Supercel may slow gastric emptying and enhance feelings of fullness, which can aid in weight management. The specific pathways and active components can vary based on formulation.

Pharmacodynamics

The pharmacodynamics of Supercel involve its ability to interact with the gastrointestinal system. Dietary fibers increase the viscosity of the intestinal contents and stimulate peristalsis, leading to improved bowel movements. The modulation of gut microbiota by soluble fibers can also have beneficial effects on metabolic health.

Pharmacokinetics

The pharmacokinetics of Supercel are largely dependent on the type and source of dietary fiber included in its formulation. Generally, dietary fibers are not digested or absorbed in the gastrointestinal tract, thus they pass through the digestive system largely intact. However, some soluble fibers can be fermented by gut bacteria, leading to the production of short-chain fatty acids which may be absorbed and utilized by the body for energy.

Pregnancy

Consult with a healthcare provider before use, as safety during pregnancy has not been established.

Breast-feeding

Consult with a healthcare provider before use, as safety during breastfeeding has not been established.

Storage

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

Dosage

Children: Refer to official guidelines or clinical resources for appropriate dosing information.

Adults: Refer to official guidelines or clinical resources for appropriate dosing information.

Pregnancy

No established data available. Consult healthcare providers before use.

Breast-feeding

No established data available. Consult healthcare providers before use.

Storage

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

Mechanism of action

Menthol primarily activates the cold-sensitive TRPM8 receptors in the skin. Menthol, after topical application, causes a feeling of coolness due to stimulation of 'cold' receptors by inhibiting Ca++ currents of neuronal membranes. It may also yield analgesic properties via kappa-opioid receptor agonism.

Pharmacodynamics

Menthol is a covalent organic compound made synthetically or obtained from peppermint or other mint oils. Menthol induces a cooling sensation on the skin upon inhalation, oral ingestion, or topical application by stimulating the cold-sensitive receptors expressed on the skin, without actually causing a drop in the skin temperature.

Mechanism of action

When administered rectally, glycerin exerts a hygroscopic and/or local irritant action, drawing water from the tissues into the feces and reflexively stimulating evacuation. Glycerin decreases intraocular pressure by creating an osmotic gradient between the blood and intraocular fluid, causing fluid to move out of the aqueous and vitreous humors into the bloodstream. Glycerin (glycerol) and sorbitol are hyperosmotic laxatives. When administered rectally, glycerin and sorbitol exert a hygroscopic and/or local irritant action, drawing water from the tissues into the feces and reflexly stimulating evacuation. The extent to which the simple physical distention of the rectum and the hygroscopic and/or local irritant actions are responsible for the laxative effects of some of these drugs is not known. Only extremely high oral doses of sorbitol (25 g daily) or glycerin exert laxative action. /Glycerin/ decreases intraocular pressure by creating an osmotic gradient between the blood and intraocular fluid, causing fluid to move out of the aqueous and vitreous humors into the bloodstream. The physicochemical effects of a series of alkanols, alkanediols and glycerol on erythrocyte shape and hemolysis at 4 and 20 degrees C were examined. We calculated the dielectric constant of the incubation medium, Ds, and the dielectric constant of the erythrocyte membrane Dm in the presence of organic solutes. The ratio Ds/Dm = -38.48 at 20 degrees C defines the normal biconcave shape in a medium without hemolytic agents. A decrease in Ds/Dm favors externalization or internalization with consequent hemolysis. Alkanols and alkanediols convert biconcave erythrocytes into echinocytes, which is accompanied by an increase in the projected surface area. Glycerol converts biconcave erythrocytes into stomatocytes, which was accompanied by a marginal decrease in the projected surface area. Progressive externalization in alkanols and alkanediols or internalization in glycerol resulted in a decrease in the projected surface area and the formation of smooth spheres. The degree of shape change induced was related to the degree of hemolysis and the ratio Ds/Dm. A decrease in temperature reduced both the degree of shape change and hemolysis. .../Thus/ physicochemical toxicity may be a result of a temperature dependent hydrophobic interaction between the organic solutes and the membrane and is best interpreted by the ability of the solutes to change Ds and Dm.

Pharmacodynamics

Glycerin is commonly classified as an osmotic laxative but may act additionally or alternatively through its local irritant effects; it may also have lubricating and fecal softening actions. Glycerin suppositories usually work within 15 to 30 minutes.

Mechanism of action

Levocetirizine selectively inhibits histamine H₁ receptors. This action prevents histamine from activating this receptor and causing effects like smooth muscle contraction, increased permeability of vascular endothelium, histidine uptake in basophils, stimulation of cough receptors, and stimulation of flare responses in the nervous system.

Pharmacodynamics

Levocetirizine is a second generation histamine H₁ antagonist used to treat various allergic symptoms. It has a long duration of action as it is generally taken once daily, and a wide therapeutic window as animal studies show the maximal nonlethal dose is over 100x a normal dose. Patients are cautioned to avoid tasks that require complete alertness, avoid alertness, and use caution in patients with factors predisposing urinary retention.