Bell's Children's Cough Syrup

Indications

• Fluid and electrolyte imbalances
• Hypoglycemia
• Nutritional supplementation
• Diabetic emergencies

Dosage

Children: Refer to the BNF for Children for appropriate paediatric dosing guidelines.

Adults: The dosage varies based on the clinical condition and specific formulation used. For intravenous administration, consult product literature for precise dosing.

Mechanism of action

Glucose supplies energy to tissues by undergoing glycolysis, which begins with its phosphorylation by hexokinase to form glucose 6-phosphate. This activates glucose for breakdown, ultimately generating ATP and NADH. The aerobic metabolism of glucose can yield up to 36 ATP molecules. Glucose also serves as a precursor for other biomolecules and regulates various physiological processes including gene transcription and hormone secretion.

Pharmacodynamics

Glucose is an obligatory energy source for cellular activities and plays a significant role in metabolic signaling. It is oxidized to yield energy through glycolysis, the citric acid cycle, and oxidative phosphorylation. Glucose can be converted into fat for energy storage and is stored as glycogen in the liver and muscles. Its administration increases blood glucose levels and stimulates insulin secretion, particularly through oral routes that activate gut incretin hormones.

Pharmacokinetics

Glucose is rapidly absorbed from the gastrointestinal tract or directly into the bloodstream when administered intravenously. It is distributed widely throughout the body and metabolized primarily in tissues requiring energy. The body maintains glucose homeostasis through regulatory mechanisms involving insulin and glucagon. Excess glucose can be stored as glycogen or converted to triglycerides for long-term energy storage.

Adverse effects

• Hyperglycemia
• Increased osmolarity
• Fluid overload
• Electrolyte imbalances

Interactions

• Insulin - may require dose adjustments

Precautions

• Use with caution in patients with diabetes mellitus
• Monitor blood glucose levels in patients receiving parenteral glucose
• Adjust dosage in renal impairment

Pregnancy

Glucose is generally considered safe in pregnancy; however, monitoring is advised, especially in diabetic patients.

Breast-feeding

Glucose is considered safe during breastfeeding, as it is a natural sugar found in breast milk.

Storage

Store at room temperature, away from light. Avoid freezing.

Formulations

• Glucose 5% solution for infusion
• Glucose 10% solution for infusion
• Glucose 0.9% solution for injection
• Glucose sodium chloride combination solutions

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

• 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

• 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

• Enhancing taste and aroma of food and beverages
• Masking undesirable flavors in food products
• Improving consumer acceptance of nutritional supplements

Dosage

Children: Refer to specific product guidelines, as dosages vary widely based on the type of flavouring agent and intended use.

Adults: Refer to specific product guidelines, as dosages vary widely based on the type of flavouring agent and intended use.

Mechanism of action

Flavouring agents primarily function by interacting with taste receptors on the tongue and olfactory receptors in the nasal cavity. These interactions stimulate sensory pathways, sending signals to the brain that contribute to the perception of taste and smell. Different flavour compounds can activate various combinations of these receptors, leading to a wide range of sensory experiences.

Pharmacodynamics

Flavouring agents do not have pharmacological effects in the way that drugs do, as they are generally regarded as safe for consumption in the amounts used in food products. Their primary role is to provide sensory stimulation rather than therapeutic benefits. However, certain flavour compounds may influence appetite or food intake by enhancing the palatability of foods.

Pharmacokinetics

The pharmacokinetics of flavouring agents can vary widely depending on their chemical structure and source. Generally, flavour compounds are absorbed through the gastrointestinal tract after ingestion and may undergo metabolic conversion in the liver. The excretion of these compounds typically occurs through urine or feces, but specific pathways depend on the individual compound.

Pregnancy

Generally considered safe when used in food and beverages, but specific flavouring agents may vary.

Breast-feeding

Generally considered safe when used in food and beverages, but specific flavouring agents may vary.

Storage

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

Formulations

• Liquid flavouring extracts
• Powdered flavouring agents
• Flavouring oils
• Flavouring syrups

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

• Cough relief
• Sore throat
• Wound healing
• Skin irritation
• Digestive issues

Dosage

Children: For children over 1 year of age, a common dosage is 1 to 2 teaspoons of honey for cough relief. Honey should not be given to children under 1 year due to the risk of botulism.

Adults: For cough relief, a common recommendation is to take 1 to 2 tablespoons of honey, as needed. Honey can be taken directly or mixed with warm water or herbal teas.

Mechanism of action

Honey exhibits various mechanisms of action, including its antibacterial and anti-inflammatory properties. The high sugar concentration creates a hypertonic environment that inhibits the growth of bacteria. Additionally, honey contains hydrogen peroxide, methylglyoxal, and flavonoids that contribute to its antimicrobial effects. The antioxidant properties of honey help in mitigating oxidative stress and promoting wound healing.

Pharmacodynamics

The pharmacodynamics of honey involve its ability to promote healing and provide symptomatic relief from coughs and sore throats. Honey's viscosity and stickiness can coat the throat, providing a soothing effect and reducing irritation. Its natural sugars also serve as an energy source, while its antioxidants may help in reducing inflammation and promoting overall health.

Pharmacokinetics

Honey is primarily absorbed in the gastrointestinal tract. The sugars in honey are rapidly metabolized, providing quick energy. The absorption rate can vary based on the composition of the honey and individual digestive factors. Honey's components, including vitamins and minerals, may also have varying rates of absorption depending on the specific nutrient and the individual's metabolism.

Adverse effects

• Allergic reactions in sensitive individuals
• Botulism in infants under 1 year

Precautions

• Should not be given to infants under 1 year due to the risk of botulism
• Use with caution in individuals with known allergies to bee products

Pregnancy

Generally considered safe for use in pregnancy, but should be consumed in moderation.

Breast-feeding

Considered safe for breastfeeding mothers and their infants over 1 year of age.

Storage

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

Formulations

• Raw honey
• Pasteurized honey
• Honey in various food products

Indications

• Scurvy prevention
• Digestive aid
• Immune system support
• Skin health
• Antimicrobial applications

Dosage

Children: There is no specific paediatric dosage for lemon; it can be given to children in moderate amounts as part of a balanced diet.

Adults: There is no specific adult dosage for lemon; it can be consumed in various forms such as fresh fruit, juice, or as part of food and beverages.

Mechanism of action

Lemon contains compounds such as citric acid, flavonoids, and essential oils. Citric acid may enhance the absorption of minerals and has a role in the Krebs cycle, promoting energy metabolism. Flavonoids possess antioxidant properties, which help combat oxidative stress and inflammation, while essential oils can exhibit antimicrobial and anti-inflammatory effects.

Pharmacodynamics

The pharmacodynamic effects of lemon are primarily attributed to its antioxidant properties, which help neutralize free radicals, reduce oxidative stress, and support overall health. The citric acid in lemon may also aid in alkalizing the body, improving metabolic processes, and supporting digestion.

Pharmacokinetics

The bioavailability of lemon compounds can vary based on the form of consumption (whole fruit, juice, or extract). Vitamin C is rapidly absorbed in the gastrointestinal tract and distributed throughout the body. The metabolism of flavonoids occurs primarily in the liver, and they may have a variable half-life depending on individual metabolism.

Adverse effects

• Allergic reactions in sensitive individuals
• Gastrointestinal discomfort
• Tooth enamel erosion with excessive use

Precautions

• Caution in individuals with citrus allergies
• May cause skin irritation if applied topically in concentrated forms

Pregnancy

Lemon is generally considered safe during pregnancy, but excessive intake should be avoided.

Breast-feeding

Lemon is safe during breastfeeding when consumed in normal dietary amounts.

Storage

Store in a cool, dry place. Fresh lemons should be kept in the refrigerator to maintain freshness.

Formulations

• Fresh lemon
• Lemon juice
• Lemon essential oil
• Lemon zest

Indications

• Soil amendment in agriculture
• Construction material
• pH regulation
• Calcium supplementation in agricultural practices

Dosage

Children: Refer to specific guidelines based on application; dosage varies based on purpose and form used.

Adults: Refer to specific guidelines based on application; dosage varies based on purpose and form used.

Mechanism of action

Lime acts by increasing the pH of the soil and promoting the availability of essential nutrients, particularly calcium. In the body, calcium ions play crucial roles in cellular signaling, muscle contraction, and neurotransmitter release. The dissolution of calcium oxide in water leads to the formation of calcium hydroxide, which increases alkalinity.

Pharmacodynamics

Calcium is vital for numerous biological functions, including bone mineralization, blood coagulation, and cellular signaling. Lime, as a source of calcium, contributes to these processes. The physiological effects of calcium are mediated through various pathways, including the modulation of ion channels and activation of calcium-dependent enzymes.

Pharmacokinetics

Calcium from lime is absorbed in the gastrointestinal tract and is subject to regulation by hormonal mechanisms, primarily involving parathyroid hormone and vitamin D. The bioavailability of calcium can be influenced by dietary factors and the presence of other compounds. Excessive calcium intake is typically excreted through the kidneys.

Pregnancy

Lime is generally considered safe during pregnancy when used in moderation, as it provides essential nutrients like calcium and vitamin C.

Breast-feeding

Lime is safe to consume during breastfeeding, as it poses no known risks to the infant and can provide beneficial nutrients.

Storage

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

Formulations

• Lime juice
• Lime powder
• Lime essential oil

Indications

• Insecticide for agricultural use
• Research tool in toxicology

Dosage

Children: Refer to the BNF for Children for specific dosing and administration guidelines.

Adults: Refer to the BNF for specific dosing and administration guidelines.

Mechanism of action

Methyl parathion acts primarily by inhibiting the enzyme acetylcholinesterase, which is essential for the breakdown of the neurotransmitter acetylcholine. Its active metabolite, methyl paraoxon, is a potent inhibitor of both acetylcholinesterase and butyrylcholinesterase. The inhibition of these enzymes results in the accumulation of acetylcholine at synapses, leading to overstimulation of cholinergic receptors and resultant toxic effects.

Pharmacodynamics

The pharmacodynamics of methyl parathion involve its action as a noncompetitive inhibitor of acetylcholinesterase, causing prolonged effects of acetylcholine due to its inability to be hydrolyzed. The resultant cholinergic toxicity can lead to symptoms such as muscle twitching, respiratory distress, and potentially fatal outcomes if not treated promptly. The extent of inhibition is dose-dependent, with significant toxicity occurring after substantial enzyme inhibition.

Pharmacokinetics

Methyl parathion is absorbed through the gastrointestinal tract and can also be absorbed through the skin and respiratory tract. It is metabolized in the liver to form methyl paraoxon, which is responsible for the majority of its toxic effects. The distribution of methyl parathion in body tissues is influenced by its lipophilicity, and it is primarily excreted as metabolites in the urine. The elimination half-life and specific pharmacokinetic parameters can vary based on individual metabolism and exposure levels.

Pregnancy

There are no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

It is not known whether this drug is excreted in human milk. Caution is advised when administering to nursing women.

Storage

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

Formulations

• Liquid formulation

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

Mechanism of action

Glucose supplies most of the energy to all tissues by generating energy molecules ATP and NADH during a series of metabolism reactions called glycolysis. Glycolysis can be divided into two main phases where the preparatory phase is initiated by the phosphorylation of glucose by hexokinase to form glucose 6-phosphate. The addition of the high-energy phosphate group activates glucose for the subsequent breakdown in later steps of glycolysis and is the rate-limiting step. Products end up as substrates for following reactions, to ultimately convert C6 glucose molecule into two C3 sugar molecules. These products enter the energy-releasing phase where the total of 4ATP and 2NADH molecules are generated per one glucose molecule. The total aerobic metabolism of glucose can produce up to 36 ATP molecules. These energy-producing reactions of glucose are limited to D-glucose as L-glucose cannot be phosphorylated by hexokinase. Glucose can act as precursors to generate other biomolecules such as vitamin C. It plays a role as a signaling molecule to control glucose and energy homeostasis. Glucose can regulate gene transcription, enzyme activity, hormone secretion, and the activity of glucoregulatory neurons. The types, number, and kinetics of glucose transporters expressed depends on the tissues and fine-tunes glucose uptake, metabolism, and signal generation to preserve cellular and whole body metabolic integrity. Vascular calcification is a hallmark of type 2 diabetes. Glucose stimulates calcification in culture of vascular smooth muscle cells (VSMCs) but the underlying mechanisms remain obscure. We observed that high glucose levels stimulated mouse and human VSMC trans-differentiation into chondrocytes, with increased levels of Sox9, type II collagen, glycosaminoglycan and Runx2 expression, and increased alkaline phosphatase activity and mineralization. These effects were associated with increased expression of IL-1beta, which stimulated alkaline phosphatase and calcification, suggesting that glucose induces chondrocyte differentiation of VSMCs, possibly through IL-1beta activation.

Pharmacodynamics

Blood glucose is an obligatory energy source for humans involved in various cellular activities, and it also acts as a signaling molecule for diverse glucose-sensing molecules and proteins. Glucose undergoes oxidation into carbon dioxide, water, and yields energy molecules in the process of glycolysis and subsequent citric cycle and oxidative phosphorylation. Glucose is readily converted into fat in the body which can be used as a source of energy as required. Under a similar conversion into storage of energy, glucose is stored in the liver and muscles as glycogen. Glucose stores are mobilized in a regulated manner, depending on the tissues' metabolic demands. Oral glucose tablets or injections serve to increase the supply of glucose and oral glucose administration is more effective in stimulating insulin secretion because it stimulates the incretin hormones from the gut, which promotes insulin secretion.

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

Acute poisoning ... is related to ... inhibiting action on enzyme acetylcholinesterase. Toxic manifestations generally occur only after more than 50% of plasma cholinesterase is inhibited. ... Methyl parathion ... depend on oxidative activation by replacement of thiono-sulfur with oxygen for ... toxicity. Methyl parathion has only a slight inhibitory action on acetylcholinesterase and butyrylcholinesterase, but its active metabolite, methyl paraoxon, is a potent inhibitor of both these enzymes. A study was conducted examining the inhibition of (Ca2+ and Mg2+)-ATPase by parathion (56382) and methyl parathion. Enzyme activity was assessed spectrophotometrically in pig erythrocyte membranes containing calcium2+ (Ca2+) and magnesium2+ and in solubilized membrane preparations incubated with the test agents. The enzyme response to ATP was biphasic. Equations expressing the kinetics of the substrate curves described two classes of the ATP binding active site, one with high affinity and low maximum rate and one with low affinity and high maximum rate. High affinity active sites were stimulated by low ATP concentrations (20 uM), whereas low affinity active sites were stimulated by high ATP levels (2 mM). Parathion and methylparathion dose dependently inhibited enzyme activity; parathion had a greater inhibitory effect than methylparathion. Lineweaver-Burke and Dixon plots indicated noncompetitive inhibition. Parathion and methylparathion induced enzyme inhibition occurred over a range of free calcium ion concentrations (0.5 to 5 mM); the inhibition was significantly greater at lower Ca2+ concentrations (1 to 100 uM) than at higher concentrations. The authors conclude that parathion and methylparathion inhibit ATPase activity by binding to a site on the enzyme rather than through an interaction with associated lipids. For more Mechanism of Action (Complete) data for METHYL PARATHION (6 total), please visit the HSDB record page.