CHX MOUTH WASH

Indications

• Oral hygiene
• Skin antisepsis
• Bladder irrigation
• Urological surgery
• Management of infections associated with indwelling urinary catheters

Mechanism of action

Chlorhexidine's antimicrobial effects arise from its ability to disrupt microbial cell membranes. The positively charged chlorhexidine molecule interacts with negatively charged phosphate groups on microbial surfaces, compromising cell integrity and causing leakage of intracellular materials. This interaction allows chlorhexidine to enter the cell, precipitate cytoplasmic components, and ultimately induce cell death. At lower concentrations, chlorhexidine acts as a bacteriostatic agent, causing leakage of substances like potassium and phosphorus, while at higher concentrations, it exerts bactericidal effects.

Pharmacodynamics

Chlorhexidine exhibits broad-spectrum antimicrobial activity, effective against a variety of bacteria, yeasts, and viruses. Its action is dose-dependent, with lower concentrations (0.02%-0.06%) providing bacteriostatic effects, while higher concentrations (>0.12%) are bactericidal. Pharmacokinetic studies indicate that about 30% of chlorhexidine remains in the mouth after rinsing, allowing for slow release into oral fluids. This property, known as 'substantivity', helps prevent microbial colonization on surfaces like dentine, although prolonged use can lead to staining of oral surfaces.

Pharmacokinetics

Chlorhexidine is retained in the oral cavity at approximately 30% following rinsing, with a slow release into saliva. The pharmacokinetics of chlorhexidine indicate a high affinity for binding to tissues, which prolongs its antimicrobial action. The systemic absorption of chlorhexidine is minimal when used topically or as a rinse, making it safe for localized use. The elimination half-life and metabolism details are not well documented due to its primarily topical application.

Adverse effects

• Mucosal irritation
• Burning sensation
• Staining of teeth and oral surfaces
• Allergic reactions

Precautions

• Use with caution in patients with a history of hypersensitivity to chlorhexidine
• May cause irritation; discontinue if severe irritation occurs
• Staining may occur with prolonged use, particularly with oral formulations

Pregnancy

Chlorhexidine is generally considered safe for use during pregnancy; however, caution is advised and pregnant individuals should consult healthcare providers.

Breast-feeding

Chlorhexidine is considered safe during breastfeeding, but it is advisable to consult a healthcare provider.

Storage

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

Formulations

• Irrigation solution (0.02% and 0.05%)
• Capsules (various strengths)
• Catheter maintenance solution (1:5000)
• Topical solutions for oral hygiene

Indications

• Methemoglobinemia
• Urinary tract infections
• Surgical marking
• Treatment of certain types of cyanide poisoning

Dosage

Children: Refer to the BNF for Children for appropriate pediatric dosing information.

Adults: Refer to the relevant clinical guidelines or the BNF for specific dosing recommendations.

Mechanism of action

Methylene blue acts as a reducing agent, converting methemoglobin back to its functional form, hemoglobin. This is primarily achieved through its action as an electron donor, facilitating the reduction of ferric iron (Fe3+) in hemoglobin to ferrous iron (Fe2+), thereby restoring its oxygen-carrying capacity. It also exhibits antimicrobial properties through its ability to generate reactive oxygen species when exposed to light, which can inhibit bacterial growth.

Pharmacodynamics

The pharmacodynamics of methylene blue involve its role in enhancing oxygen delivery in patients suffering from methemoglobinemia. By converting methemoglobin back to hemoglobin, it effectively increases the amount of hemoglobin available for oxygen transport. The drug also shows effects on the vascular system, where it can induce vasodilation and influence blood pressure.

Pharmacokinetics

Methylene blue is rapidly absorbed after intravenous administration, with peak plasma concentrations occurring within 1 to 3 hours. It is extensively distributed in body tissues and fluids, including the liver, kidneys, and lungs. The drug undergoes hepatic metabolism, primarily through the cytochrome P450 system, and is excreted mainly through urine. The half-life ranges from 5 to 24 hours, depending on the dosage and individual patient factors.

Pregnancy

Consult healthcare provider before use, as safety in pregnancy is not established.

Breast-feeding

Consult healthcare provider before use, as safety during breastfeeding is not established.

Storage

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

Indications

• Surgical staining
• Diagnostic staining in histology
• Visualization of structures in ophthalmic procedures

Dosage

Children: Refer to specific guidelines for application based on the procedure and context. Dosage is typically determined by the healthcare provider depending on the clinical scenario.

Adults: Refer to specific guidelines for application based on the procedure and context. Dosage is typically determined by the healthcare provider depending on the clinical scenario.

Mechanism of action

Brilliant Blue FCF exerts its effects by binding to proteins and tissues, allowing for clear visualization during surgical procedures. The dye absorbs light at specific wavelengths, making it useful for highlighting structures in biological tissues.

Pharmacodynamics

Brilliant Blue FCF has minimal systemic absorption when used as a local stain, leading to localized effects primarily at the site of application. Its primary role is as a visual aid rather than having therapeutic effects on biological processes.

Pharmacokinetics

When applied topically, Brilliant Blue FCF is minimally absorbed systemically. The dye is excreted primarily unchanged in the urine. Due to its low bioavailability and rapid clearance, systemic toxicity is rare, making it safe for local use in surgical and diagnostic settings.

Pregnancy

Safety during pregnancy has not been established. 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 should be exercised when administering to nursing mothers.

Storage

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

Pregnancy

There is limited data on the safety of color additives during pregnancy. Use only if clearly needed and after consultation with a healthcare provider.

Breast-feeding

The safety of color additives during breastfeeding is not well studied. Use with caution and consult a healthcare provider.

Storage

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

Indications

• To enhance the palatability of oral medications
• To improve compliance in pediatric patients
• To mask unpleasant tastes of active pharmaceutical ingredients

Dosage

Children: Refer to specific formulations for guidance, as flavoring agents are typically used in very small quantities and are not dosed independently.

Adults: Refer to specific formulations for guidance, as flavoring agents are typically used in very small quantities and are not dosed independently.

Mechanism of action

Flavor compounds act primarily by stimulating taste receptors on the tongue, which can enhance the overall sensory experience of ingesting a product. Certain flavor compounds may also interact with olfactory receptors, contributing to the perception of flavor through smell. The stimulation of these receptors can lead to increased salivation and improved swallowing.

Pharmacodynamics

The use of flavoring agents in pharmaceuticals can influence compliance, particularly in children and individuals who may have difficulty swallowing pills. By enhancing the taste of a medication, these agents can reduce gag reflex and aversion, potentially improving therapeutic outcomes. However, the pharmacodynamic effects are largely dependent on the individual's taste preferences and sensitivities.

Pharmacokinetics

The pharmacokinetics of flavoring agents vary widely depending on the specific compounds used. Generally, these compounds are rapidly absorbed through the gastrointestinal tract upon ingestion, with their effects occurring within minutes. Some flavoring agents may undergo metabolism in the liver, while others may be excreted unchanged. The specific absorption, distribution, metabolism, and excretion (ADME) profiles depend on the chemical structure of each flavor compound.

Pregnancy

Generally considered safe, but specific flavoring agents may need to be evaluated individually.

Breast-feeding

Generally considered safe, but specific flavoring agents may need to be evaluated individually.

Storage

Store in a cool, dry place away from light and moisture.

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: Paediatric fluid requirements should be calculated based on age, weight, and clinical condition. Refer to the guidelines in the BNF for Children for detailed recommendations.

Adults: Dosage in litres may vary depending on clinical circumstances, such as fluid resuscitation needs, maintenance fluid requirements, or medication delivery. Refer to clinical guidelines for specific scenarios.

Mechanism of action

Litres do not have a pharmacological mechanism of action as they are a unit of measurement rather than a drug. However, the administration of fluids measured in litres can influence various physiological processes, including hydration status, electrolyte balance, and overall fluid homeostasis in the body.

Pharmacodynamics

As a measurement unit, litres do not exhibit pharmacodynamics. However, the volume of fluid administered can impact the pharmacodynamics of medications that are diluted or delivered in fluid form, affecting the rate of absorption, distribution, metabolism, and excretion of drugs.

Pharmacokinetics

Litres as a unit of volume do not possess pharmacokinetic properties. The pharmacokinetics of a drug may be influenced by the volume of fluid in which it is administered, as this can affect the concentration of the drug in the bloodstream and its subsequent pharmacological effects.

Indications

• Topical analgesic for muscle and joint pain
• Cough suppressant in cough drops and lozenges
• Relief of minor throat irritation
• Cooling agent in various cosmetic and personal care products

Dosage

Children: Refer to BNF for Children for specific dosing guidelines, as doses may vary based on age and formulation.

Adults: For topical use, apply a thin layer to the affected area not more than 3 to 4 times daily. For cough drops, follow the product-specific instructions as per the formulation.

Mechanism of action

Menthol acts as an agonist for the transient receptor potential subtype M8 (TRPM8), a non-selective cation channel that is activated by cold temperatures. This activation leads to calcium influx in mast cells, inducing the release of histamine, which can trigger allergic responses such as urticaria, asthma, and rhinitis. Menthol's ability to induce histamine release via TRPM8 suggests potential therapeutic applications for TRPM8 antagonists in managing cold- and menthol-induced allergies.

Pharmacodynamics

Menthol produces a cooling effect by stimulating sensory neurons that convey cold sensations. It interacts with TRPM8 channels, leading to the activation of intracellular signaling pathways that can result in vasodilation and increased blood flow to the area of application. This cooling sensation can provide symptomatic relief in conditions characterized by pain or irritation.

Pharmacokinetics

Menthol is absorbed through the skin and mucous membranes, with systemic effects depending on the route of administration. Its bioavailability can vary, and it is metabolized primarily in the liver. The elimination half-life and excretion pathways have not been extensively characterized, but menthol is generally considered to have a rapid onset of action with effects lasting for a few hours.

Adverse effects

• Allergic reactions
• Urticaria
• Asthma
• Rhinitis
• Skin irritation

Precautions

• Use with caution in patients with known allergies to menthol or related compounds
• May exacerbate asthma in sensitive individuals

Pregnancy

There are no well-controlled studies of menthol in pregnant women. Menthol should be used during pregnancy only if clearly needed.

Breast-feeding

Menthol is excreted in breast milk. Caution should be exercised when administering to nursing mothers.

Storage

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

Formulations

• Topical ointment
• Cream
• Liquid

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

• Solvent for pharmaceuticals
• Preparation of tinctures
• Antiseptic applications
• Industrial uses

Dosage

Children: Refer to specific medical guidelines and consult a pediatric pharmacologist.

Adults: Refer to specific medical guidelines for appropriate use as a solvent or antiseptic.

Mechanism of action

Ethanol, the active component of rectified spirits, influences the central nervous system by acting primarily as a positive allosteric modulator of the GABA-A receptor, enhancing inhibitory neurotransmission. It also affects various neurotransmitter systems, including dopamine and serotonin pathways, which contributes to its psychoactive effects.

Pharmacodynamics

The pharmacodynamic effects of rectified spirits are dose-dependent, with low doses resulting in mild euphoria and relaxation, and higher doses leading to significant sedation, impaired motor function, and altered cognitive function. Chronic use can lead to tolerance and dependence, along with a range of health issues, including liver disease and neurological impairment.

Pharmacokinetics

Ethanol is absorbed rapidly through the gastrointestinal tract, with peak blood concentrations typically occurring within 30 to 90 minutes after ingestion. It is metabolized primarily in the liver by enzymes such as alcohol dehydrogenase and aldehyde dehydrogenase, and its elimination follows zero-order kinetics at higher concentrations. The half-life of ethanol can vary widely based on individual factors such as metabolic rate, age, and liver health.

Pregnancy

Data on the safety of rectified alcohol during pregnancy is limited. It is advisable to avoid use during pregnancy due to potential risks to the fetus.

Breast-feeding

Caution is advised when using rectified alcohol while breastfeeding, as it may affect lactation and the nursing infant.

Storage

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

Indications

• Constipation
• Diagnostic aid in colonoscopy preparation
• Management of hyperosmolality in various conditions

Dosage

Children: For children, the dosage should be determined based on age and condition, and it is advised to refer to the BNF for Children for specific dosing guidelines.

Adults: The typical dose for adults is 30 to 150 mL of sorbitol solution (70%) taken orally, as needed, usually before bedtime.

Mechanism of action

Sorbitol exerts its laxative effect by drawing water into the large intestine, thereby stimulating bowel movements. It acts as a hygroscopic agent, pulling water from tissues into the feces, which reflexively stimulates evacuation. In metabolic pathways, sorbitol is produced from glucose via aldose reductase and is converted to fructose by sorbitol dehydrogenase, with implications in diabetic complications such as retinopathy.

Pharmacodynamics

Sorbitol's laxative effect results from its osmotic properties, which increase the water content of the stool and soften it, facilitating easier passage. Additionally, sorbitol can induce apoptosis in certain cancer cell lines, indicating potential therapeutic implications beyond its laxative use. The modulation of intracellular signaling pathways through the regulation of proteins such as Bax and Bcl-2 suggests a complex role in cellular health and disease.

Pharmacokinetics

Sorbitol is poorly absorbed in the gastrointestinal tract, which contributes to its efficacy as a laxative. It is metabolized in the liver, primarily through the polyol pathway. The absorption and distribution of sorbitol are affected by its osmotic properties, leading to increased intestinal water retention. Its elimination is primarily via renal excretion, with minimal systemic absorption, thus reducing the risk of systemic side effects.

Adverse effects

• Diarrhea
• Abdominal cramps
• Nausea
• Vomiting
• Electrolyte imbalances

Precautions

• Use with caution in patients with renal impairment
• May exacerbate gastrointestinal conditions

Pregnancy

Sorbitol is generally considered safe during pregnancy, but should be used under medical supervision.

Breast-feeding

Sorbitol is excreted in breast milk in small amounts; consult a healthcare provider before use.

Storage

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

Formulations

• Oral solution
• Syrup

Indications

• Digestive discomfort
• Nausea
• Anxiety relief
• Respiratory conditions
• Flavoring agent

Dosage

Children: Refer to established guidelines or consult a healthcare professional for appropriate dosing.

Adults: Refer to established guidelines or consult a healthcare professional for appropriate dosing.

Mechanism of action

The active compounds in spearmint, particularly carvone and limonene, exert their effects by influencing the central nervous system and gastrointestinal system. Carvone has been shown to exhibit antispasmodic properties, which may alleviate digestive discomfort. Additionally, the oil may have antimicrobial properties that contribute to its use in oral hygiene products.

Pharmacodynamics

Spearmint is known for its ability to relax smooth muscles in the gastrointestinal tract, which can help reduce symptoms of indigestion and bloating. Its aromatic qualities can enhance mood and reduce anxiety levels, promoting a sense of calm. The anti-inflammatory properties may also play a role in alleviating symptoms of respiratory conditions.

Pharmacokinetics

When consumed, the active components of spearmint are metabolized primarily in the liver. The absorption of spearmint oil compounds varies based on the method of ingestion and individual metabolic differences. The bioavailability of carvone and other monoterpenes can be influenced by their solubility and the presence of other dietary components.

Adverse effects

• Allergic reactions
• Gastrointestinal upset
• Mouth and throat irritation

Precautions

• Use with caution in individuals with allergies to mint family plants
• May exacerbate gastroesophageal reflux disease (GERD)

Pregnancy

Spearmint is generally considered safe in food amounts during pregnancy, but high doses should be avoided due to potential hormonal effects.

Breast-feeding

Spearmint is likely safe in food amounts while breastfeeding, but excessive consumption should be avoided.

Storage

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

Formulations

• Essential oil
• Dried leaves
• Teas
• Extracts

Indications

• Antiseptic use
• Solvent in pharmaceutical preparations
• Management of alcohol withdrawal syndrome
• Treatment of methanol poisoning (as an antidote)

Dosage

Children: Refer to specific medical guidelines or formularies for dosing information, as it varies widely based on the indication and formulation used.

Adults: Refer to specific medical guidelines or formularies for dosing information, as it varies widely based on the indication and formulation used.

Mechanism of action

Ethanol acts primarily by enhancing the effects of the neurotransmitter gamma-aminobutyric acid (GABA) at the GABA-A receptor, leading to increased inhibitory neurotransmission. It also inhibits the N-methyl-D-aspartate (NMDA) receptor, which contributes to its depressant effects. Additionally, ethanol affects the release of various neurotransmitters, including dopamine, which plays a role in the reward pathway and contributes to its addictive properties.

Pharmacodynamics

Ethanol's pharmacodynamic effects are dose-dependent. Low doses can produce mild euphoria, relaxation, and impaired motor coordination. As the dose increases, effects can progress to sedation, respiratory depression, and potentially coma or death in cases of severe intoxication. Chronic use can lead to tolerance and dependence, with withdrawal symptoms occurring upon cessation.

Pharmacokinetics

Ethanol is rapidly absorbed from the gastrointestinal tract, with peak blood concentrations occurring within 30 to 90 minutes after ingestion. It is distributed throughout body water, with a volume of distribution of approximately 0.5 to 0.7 L/kg. Ethanol is metabolized primarily by the liver through the action of alcohol dehydrogenase and aldehyde dehydrogenase, with a typical elimination rate of 10 to 20 mg/dL per hour. It is excreted in urine, breath, and sweat.

Adverse effects

• Nausea
• Vomiting
• Dizziness
• Headache
• Irritation of mucous membranes
• Depression of the central nervous system

Interactions

• Increased sedation with other CNS depressants
• Potential enhancement of effects of certain medications metabolized by the liver

Precautions

• Use with caution in patients with a history of substance abuse
• Monitor for signs of excessive sedation or respiratory depression
• Avoid use in patients with known hypersensitivity to alcohol or other ingredients

Pregnancy

Alcohol is generally advised against during pregnancy due to risks of fetal alcohol spectrum disorders and other complications.

Breast-feeding

Alcohol can pass into breast milk, and breastfeeding mothers should limit intake to avoid potential effects on the infant.

Storage

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

Formulations

• Spirit (ethanol-based liquid)
• Spirit of ammonia
• Spirit of camphor
• Spirit of turpentine

Indications

• Used as an emulsifier in pharmaceutical formulations
• Improving the solubility of poorly soluble drugs
• Stabilizing emulsions in topical and oral medications
• Used in laboratory settings as a surfactant

Dosage

Children: Dosage varies based on formulation and intended use, refer to specific product guidelines.

Adults: Dosage varies based on formulation and intended use, refer to specific product guidelines.

Mechanism of action

Tween works by reducing the surface tension of the liquid it is mixed with, allowing for better mixing of hydrophilic and hydrophobic substances. This property makes it effective in enhancing the delivery of drugs that are poorly soluble in water. Tween can also stabilize emulsions by forming a protective layer around droplets, preventing them from coalescing.

Pharmacodynamics

As a surfactant, Tween enhances the solubility of lipophilic compounds and improves the absorption of drugs through biological membranes. Its application in drug formulation can lead to increased bioavailability and improved therapeutic effects, especially for poorly soluble drugs.

Pharmacokinetics

Tween is generally not absorbed significantly in the gastrointestinal tract when ingested. Instead, it has a local effect in the gastrointestinal tract and may influence the absorption of other compounds. The metabolism of Tween is not well characterized, and its excretion primarily occurs through feces. The overall pharmacokinetic profile is influenced by the specific formulation in which it is used.

Pregnancy

Tween (polysorbate 20) is generally considered safe for use during pregnancy. However, it should be used only when clearly needed and after consultation with a healthcare provider.

Breast-feeding

Tween is considered safe for use during breastfeeding. Its absorption and systemic exposure are minimal, but it is advisable to consult a healthcare provider.

Storage

Store at room temperature, away from moisture and heat. Keep tightly closed in a cool, dry place.

Mechanism of action

Chlorhexidine’s broad-spectrum antimicrobial effects are due to its ability to disrupt microbial cell membranes. The positively charged chlorhexidine molecule reacts with negatively charged phosphate groups on microbial cell surfaces - this reaction both destroys the integrity of the cell, allowing leakage of intracellular material, and allows chlorhexidine to enter the cell, causing precipitation of cytoplasmic components and ultimately cell death. The specific means of cell death is dependent on the concentration of chlorhexidine - lower concentrations are bacteriostatic and result in leakage of intracellular substances such as potassium and phosphorous, whereas higher concentrations are bactericidal and cause cytoplasmic precipitation.

Pharmacodynamics

Chlorhexidine is a broad-spectrum antimicrobial with demonstrated activity against both gram-positive and gram-negative bacteria, yeasts, and viruses. Antimicrobial activity is dose-dependent - chlorhexidine is bacteriostatic at lower concentrations (0.02%-0.06%) and bactericidal at higher concentrations (>0.12%). Pharmacokinetic studies of oral chlorhexidine rinses indicate that approximately 30% of the active ingredient is retained in the mouth following rinsing, which is subsequently slowly released into oral fluids. This ability to adsorb to dentine, shared with tetracycline antibiotics such as [doxycycline], is known as "substantivity" and is the result of chlorhexidine's positive charge - it is likely that this substantivity plays at least some role in chlorhexidine's antimicrobial activity, as its persistence on surfaces such as dentine prevent microbial colonization. Dental chlorhexidine rinses may result in staining of oral surfaces, such as teeth. This effect is not ubiquitous and appears to be more significant with extended therapy (i.e. up to 6 months) - nevertheless, patients for whom oral staining is unacceptable should use chlorhexidine rinse with caution and for the shortest effective interval. Allergic reactions to chlorhexidine have been associated with the development of anaphylaxis.

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.

Mechanism of action

Exposure to low temperatures often causes allergic responses or urticaria. Similarly, menthol, a common food additive is also known to cause urticaria, asthma, and rhinitis. However, despite the obvious clinical implications, the molecular mechanisms responsible for inducing allergic responses to low temperatures and menthol have not been determined. Because a non-selective cation channel, transient receptor potential subtype M8 (TRPM8) is activated by cold and menthol, we hypothesized that this channel mediates cold- and menthol-induced histamine release in mast cells. Here, we report that TRPM8 is expressed in the basophilic leukemia mast cell line, RBL-2H3, and that exposure to menthol or low temperatures induced Ca(2+) influx in RBL-2H3 cells, which was reversed by a TRPM8 blocker. Furthermore, menthol, a TRPM8 agonist, induced the dose-dependent release of histamine from RBL-2H3 cells. When TRPM8 transcripts were reduced by siRNA (small interfering RNA), menthol- and cold-induced Ca(2+) influx and histamine release were significantly reduced. In addition, subcutaneous injection of menthol evoked scratching, a typical histamine-induced response which was reversed by a TRPM8 blocker. Thus, our findings indicate that TRPM8 mediates the menthol- and cold-induced allergic responses of mast cells, and suggest that TRPM8 antagonists be viewed as potential treatments for cold- and menthol-induced allergies. /DL-Menthol/ Menthol's characteristic cooling sensation is due, in part, to the activation of sensory neurons generally termed transient receptor potential (TRP) channels, in particular transient receptor potential melastatin family member 8 (TRPM8) and transient receptor potential subfamily A, member 1 (TRPA1). Menthol acts upon TRPM8 receptors by rapidly increasing intracellular calcium and mobilizing calcium flux through the channels to induce cold response signals at the application site. Aside from its cold-inducing sensation capabilities, menthol exhibits cytotoxic effects in cancer cells, induces reduction in malignant cell growth, and engages in synergistic excitation of GABA receptors and sodium ion channels resulting in analgesia. /DL-Menthol/ In recent years, the transient receptor potential melastatin member 8 (TRPM8) channel has emerged as a promising prognostic marker and putative therapeutic target in prostate cancer. We have found that forced overexpression of TRPM8 in PC-3 cells can inhibit the cell proliferation and motility probably through the TRPM8 activation. In this study, we aimed to investigate whether activating the TRPM8 channel by its selective agonist menthol can inhibit the proliferation and motility of androgen-independent prostate cancer (AIPC) with remarkable expression of TRPM8. Menthol is a naturally occurring compound, which has been widely used in cosmetics and pharmaceutical products, and also as flavoring in food. DU145 cells are androgen-independent but have a remarkable expression of TRPM8. The demonstration of the existence of TRPM8 and the absence of TRPA1 in DU145 cells provided the foundation for the following experiments, because both TRPM8 and TRPA1 are molecular targets of menthol. The outcome of MTT assay indicated that menthol inhibited the cell growth (p < 0.01). Cell cycle distribution and scratch assay analysis revealed that menthol induced cell cycle arrest at the G(0)/G(1) phase (p < 0.01). Furthermore, menthol inhibited the migration of DU145 cells by downregulating the focal-adhesion kinase. So it suggests that the activation of the existing TRPM8 channels may serve as a potential and pragmatic treatment for those AIPC with remarkable expression of TRPM8, and menthol is a useful compound for future development as an anticancer agent. /DL-Menthol/

Mechanism of action

Sorbitol exerts its laxative effect by drawing water into the large intestine, thereby stimulating bowel movements. ... Sorbitol exerts hygroscopic and/or local irritant action, drawing water from tissues into feces and reflexly stimulating evacuation. The polyol pathway consists of two enzymes aldose reductase (AR) and sorbitol dehydrogenase (SDH); the former is the first enzyme in the polyol pathway, that catalyzes the reduction of glucose to sorbitol, the latter is the second one, that converts sorbitol to fructose using by NAD(+) as a cofactor. ... SDH activity, the second step in the polyol pathway, might make a greater contribution to the etiology of diabetic retinopathy than does the first step involving AR. /This paper proposes/ a novel hypothesis that polymorphisms of SDH gene may be correlated with SDH gene expression levels in diabetic retinas, thus being a valuable genetic marker for diabetic retinopathy. It has been reported that sorbitol induces apoptosis in several cancer cell lines. ... In /this/ study, the intracellular signaling pathways of sorbitol-induced apoptosis in human K562 cells were investigated using both morphological analysis and DNA fragmentation technique. In this study, we demonstrated that sorbitol-induced apoptosis in human K562 cells is a concentration- and time-dependent manner. This sorbitol-induced apoptosis in human K562 cells was also accompanied by the up-regulation of Bax, and down-regulation of p-Bcl-2, but no effect on the levels of Bcl-X(L). Moreover, the sorbitol treatment resulted in a significant reduction of mitochondria membrane potential, increase in the release of mitochondrial cytochrome c (cyt c), and activation of caspase 3. Furthermore, treatment with caspase 3 inhibitor (z-DEVD-fmk) was capable of preventing the sorbitol-induced caspase 3 activity and cell death. These results clearly demonstrate that the induction of apoptosis by sorbitol involves multiple cellular/molecular pathways and strongly suggest that pro- and anti-apoptotic Bcl-2 family proteins, mitochondrial membrane potential, mitochondrial cyt c, and caspase 3, they all participate in sorbitol-induced apoptotic process in human K562 cells. Chronic diabetic complications, in particular, nephropathy, peripheral and autonomic neuropathy, "diabetic foot," retinopathy, and cardiovascular disease, remain the major cause of morbidity and mortality in patients with diabetes mellitus. Growing evidence indicates that both increased activity of the sorbitol pathway of glucose metabolism and enhanced oxidative stress are the leading factors in the pathogenesis of diabetic complications. The relation between the two mechanisms remains the area of controversy. One group has reported that increased sorbitol pathway activity has a protective rather than detrimental role in complication-prone tissues because the pathway detoxifies toxic lipid peroxidation products. Others put forward a so-called "unifying hypothesis" suggesting that activation of several major pathways implicated in diabetic complications (eg, sorbitol pathway) occurs due to increased production of superoxide anion radicals in mitochondria and resulting poly(ADP-ribose) polymerase activation. This review (a) presents findings supporting a key role for the sorbitol pathway in oxidative stress and oxidative stress-initiated downstream mechanisms of diabetic complications, and (b) summarizes experimental evidence against a detoxifying role of the sorbitol pathway, as well as the "unifying concept."