Gentian Violet

Indications

• Hepatic encephalopathy
• Urea cycle disorders
• Acid-base disturbances

Dosage

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

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

Mechanism of action

Ammonia is crucial for renal excretion and metabolism, which aids in the regulation of acid-base balance by generating bicarbonate ions and promoting renal net acid excretion. Acute exposure to ammonia can activate NMDA receptor signaling pathways, while high concentrations resulting from urea cycle enzyme deficiencies can cause alterations in astrocyte morphology and increased neuroactive metabolites. This includes oxidative/nitrosative stress that impacts neuronal and astrocytic function, contributing to cerebral ammonia toxicity and related neuropsychiatric effects.

Pharmacodynamics

As a gas, ammonia acts as a natural respiratory stimulant. Its renal metabolism contributes to whole body acid-base balance, while its toxic effects at elevated levels can lead to significant neurophysiological changes, particularly in the context of liver dysfunction. Ammonia's role in stimulating oxidative stress responses in brain cells can lead to cellular damage and altered signaling pathways.

Pharmacokinetics

Ammonia is primarily metabolized in the liver, where it is converted to urea through the urea cycle, facilitating its excretion. The balance of ammonia production and clearance is critical for maintaining normal physiological functions. Following inhalation, ammonia is rapidly absorbed and can cause irritation in the respiratory tract. Renal function significantly influences ammonia levels in the body, with changes in kidney function affecting its excretion and thus systemic concentrations.

Pregnancy

Ammonia is generally considered unsafe during pregnancy due to potential risks to fetal development.

Breast-feeding

Ammonia may be present in breast milk; caution is advised.

Storage

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

Indications

• Alcohol use disorder
• Acute alcohol intoxication
• Antiseptic for skin disinfection

Mechanism of action

Ethanol affects the brain’s neurons in several ways. It alters their membranes, ion channels, enzymes, and receptors. Ethanol binds directly to the receptors for acetylcholine, serotonin, GABA, and NMDA receptors for glutamate. The sedative effects are mediated through binding to GABA receptors and glycine receptors, while also inhibiting NMDA receptor functioning. As an anti-infective, ethanol acts as an osmolyte, disrupting the osmotic balance across cell membranes. The acute effects result from competitive inhibition of glycine binding to NMDA receptors, leading to disrupted glutamatergic neurotransmission.

Pharmacodynamics

Ethanol produces cellular injury through dehydration and precipitation of cytoplasm, contributing to its bactericidal and antifungal actions. It can lead to neuritis and nerve degeneration when injected near nerve tissues. Up to 98% of ethanol in the body is oxidized, primarily by the hepatic enzyme alcohol dehydrogenase. Its modulation of neurotransmitter receptors, particularly GABA and NMDA, leads to its sedative properties and potential for developing tolerance with chronic use.

Pharmacokinetics

Ethanol is readily absorbed from the gastrointestinal tract and distributed throughout the body. It has a volume of distribution of approximately 0.5 to 0.6 L/kg. Ethanol is metabolized predominantly in the liver by alcohol dehydrogenase to acetaldehyde, which is further oxidized to acetic acid by aldehyde dehydrogenase. The elimination half-life of ethanol varies but is generally around 4 to 5 hours. Factors such as age, sex, body weight, and genetic variability can influence ethanol metabolism.

Contra-indications

• Hypersensitivity to ethanol
• Acute alcohol intoxication
• Severe liver disease
• Pregnancy (in non-medicinal use)
• Severe pancreatitis
• Severe head injury or intracranial bleeding

Adverse effects

• Dizziness
• Nausea
• Vomiting
• Headache
• Sedation
• Cognitive impairment
• Respiratory depression
• Hypotension
• Gastrointestinal bleeding
• Alcohol withdrawal syndrome

Interactions

• CNS depressants (e.g., benzodiazepines, opioids) may enhance sedative effects
• Disulfiram may cause unpleasant reactions when taken with ethanol
• Acetaminophen may increase hepatic toxicity when used with ethanol
• Warfarin may have altered effects when used with ethanol

Precautions

• Caution in patients with a history of alcohol abuse
• Use with caution in patients with hepatic impairment
• Monitor for signs of respiratory depression
• Consider potential for addiction and withdrawal symptoms
• Use in moderation in older adults due to increased sensitivity

Pregnancy

Ethanol should be avoided during pregnancy due to the risk of fetal alcohol spectrum disorders.

Breast-feeding

Ethanol can pass into breast milk; breastfeeding should be avoided for a minimum of 2 hours after consumption.

Storage

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

Formulations

• Oral solutions
• Topical antiseptics
• Intravenous formulations
• Medicinal tinctures

Indications

• Loss of appetite
• Dyspepsia
• Gastrointestinal disorders
• Digestive aid
• Bloating

Dosage

Children: Refer to established herbal guidelines, as specific dosing may vary based on preparation and indication.

Adults: Refer to established herbal guidelines, as specific dosing may vary based on preparation and indication.

Mechanism of action

The primary mechanism of action of gentian is attributed to its bitter compounds, which stimulate the taste receptors in the mouth and gastrointestinal tract. This stimulation increases the secretion of digestive juices, including saliva, gastric acid, and bile, thereby enhancing digestion and appetite. The presence of secoiridoids may also exert anti-inflammatory and antioxidant effects, contributing to its overall benefits.

Pharmacodynamics

Gentian exhibits pharmacodynamic effects primarily through its bitter principles that promote digestive processes. These compounds increase gastrointestinal motility and enhance nutrient absorption by stimulating the secretion of digestive enzymes. Gentian's potential effects on appetite regulation may also involve central nervous system pathways, although this mechanism is less well understood.

Pharmacokinetics

The pharmacokinetics of gentian are not extensively characterized due to its herbal nature. However, it is generally assumed that the active compounds are absorbed in the gastrointestinal tract after oral administration. The metabolism and excretion pathways remain largely undefined, given the complexity of the herbal preparation and the variability in individual responses.

Pregnancy

The safety of gentian during pregnancy has not been established. Use should be avoided unless deemed necessary by a healthcare professional.

Breast-feeding

Limited information is available on the excretion of gentian in breast milk. Caution is advised when administering to breastfeeding mothers.

Storage

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

Indications

• Management of hyperoxaluria
• Prevention of calcium oxalate kidney stones
• Assessment of metabolic disorders related to oxalate

Dosage

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

Adults: Refer to the BNF for specific dosing guidelines.

Mechanism of action

Oxalate primarily functions as a metabolic byproduct in various pathways. It is involved in the superpathway of glycolysis and the tricarboxylic acid (TCA) cycle. In plants, oxalate can play a part in regulating calcium levels and can affect the solubility of calcium and other minerals, influencing mineral absorption. In humans, high levels of oxalate can lead to the formation of insoluble calcium oxalate crystals, contributing to kidney stone formation.

Pharmacodynamics

Oxalate interacts with calcium in the body, leading to the formation of calcium oxalate, which is poorly soluble. This property is critical in the context of kidney stone formation, as elevated oxalate levels can increase the risk of crystallization and subsequent stone development. The balance of oxalate in the body is influenced by dietary intake, metabolic processes, and renal excretion.

Pharmacokinetics

Oxalate is absorbed from the gastrointestinal tract and is also produced endogenously. Once in the bloodstream, it is primarily excreted by the kidneys. The renal clearance of oxalate is significant, and reduced kidney function can lead to elevated serum and urine oxalate levels, increasing the risk for stone formation. Factors such as hydration, dietary oxalate, and calcium intake can influence oxalate metabolism and excretion.

Pregnancy

There is no specific information available regarding the use of oxalate during pregnancy.

Breast-feeding

There is no specific information available regarding the use of oxalate during breastfeeding.

Storage

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

Formulations

• {'formulation': 'Oxalate salt', 'description': 'Used in various formulations, particularly in laboratory and industrial applications.'}

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.

Dosage

Children: Refer to specific product information for details on use as a coloring agent in formulations.

Adults: Refer to specific product information for details on use as a coloring agent in formulations.

Mechanism of action

The mechanism of action for violet dyes generally involves their ability to absorb specific wavelengths of light, which contributes to their coloring properties. In the context of pharmacology, they do not possess therapeutic effects but rather serve a functional role in drug formulation.

Pharmacodynamics

As a coloring agent, violet dyes do not exhibit pharmacodynamic properties associated with therapeutic agents. They do not interact with biological targets in the manner that active pharmaceutical ingredients do, and their primary role is to provide color rather than therapeutic efficacy.

Pharmacokinetics

Violet dyes, being non-active agents, do not undergo typical pharmacokinetic processes such as absorption, distribution, metabolism, and excretion in the same way that active drugs do. Their presence in formulations is primarily for aesthetic purposes, and they are typically excreted unchanged.

Pregnancy

Safety not established; consult healthcare provider.

Breast-feeding

Safety not established; consult healthcare provider.

Storage

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

Mechanism of action

Renal excretion and metabolism of ammonia is critical in regulation of acid-base balance by generating bicarbonate ions and promoting renal net acid excretion, both under basal conditions and in response to acid-base disturbances. There is evidence that acute ammonia exposure activates NMDA receptor signalling pathways, and high concentrations of ammonia resulting from urea cycle enzyme deficiencies are associated with changes in astrocyte morphology due to glutamine accumulation, changes in the expression of key astrocyte proteins, and increased concentrations of neuroactive L-tryptophan metabolites. ... Ammonia plays a key role in the pathogenesis of hepatic encephalopathy, which manifests as a neuropsychiatric syndrome accompanying acute and chronic liver failure. One consequence of ammonia action on the brain is astrocyte swelling, which triggers the generation of oxidative/nitrosative stress at the level of NADPH oxidase, nitric oxide synthases and the mitochondria. A self-amplifying signaling loop between oxidative stress and astrocyte swelling has been proposed. Consequences of the ammonia-induced oxidative/nitrosative stress response are protein modifications through nitration of tyrosine residues and oxidation of astrocytic and neuronal RNA. Nitrosative stress also mobilizes zinc from intracellular stores with impact on gene expression. These alterations may at least in part mediate cerebral ammonia toxicity through disturbances of intracellular and intercellular signaling and of synaptic plasticity. Oxidative/nitrosative stress and a low-grade cerebral edema as key events in the pathogenesis of ammonia toxicity and hepatic encephalopathy may offer potential new strategies for treatment. Ammonia-induced oxidation of RNA and proteins may impair postsynaptic protein synthesis, which is critically involved in learning and memory consolidation. RNA oxidation offers a novel explanation for multiple disturbances of neurotransmitter systems and gene expression and the cognitive deficits observed in hepatic encephalopathy. SRP: Ammonia in an aqueous environment exists in equilibrium between ionized ammonium cation and the non-ionized ammonia. This equilibrium can be affected by buffers, pH, temperature, and salinity. Thus in many cases it is not possible to assign the associated toxicity to the ionized or non-ionized form of the ammonia-nitrogen. /Aqueous ammonia/ Mechanisms involved in hepatic encephalopathy (HE) still remain poorly understood. It is generally accepted that ammonia plays a major role in this disorder, and that astrocytes represent the principal target of ammonia neurotoxicity. In recent years, studies from several laboratories have uncovered a number of factors and pathways that appear to be critically involved in the pathogenesis of this disorder. Foremost is oxidative and nitrosative stress (ONS), which is largely initiated by an ammonia-induced increase in intracellular Ca(2+). Such increase in Ca(2+) activates a number of enzymes that promote the synthesis of reactive oxygen-nitrogen species, including constitutive nitric oxide synthase, NADPH oxidase and phospholipase A2. ONS subsequently induces the mitochondrial permeability transition, and activates mitogen-activated protein kinases and the transcription factor, nuclear factor-kappaB (NF-kappaB). These factors act to generate additional reactive oxygen-nitrogen species, to phosphorylate various proteins and transcription factors, and to cause mitochondrial dysfunction. This article reviews the role of these factors in the mechanism of HE and ammonia toxicity with a focus on astrocyte swelling and glutamate uptake, which are important consequences of ammonia neurotoxicity.... A new model for ammonia excretion in freshwater fish and its variable linkage to Na(+) uptake and acid excretion /is proposed/. In this model, /the Rhesus protein/ Rhag facilitates NH(3) flux out of the erythrocyte, Rhbg moves it across the basolateral membrane of the branchial i

Pharmacodynamics

As a gas, ammonia is a natural byproduct and respiratory stimulant. Its renal metabolism plays a role in whole body acid-base balance.

Mechanism of action

Ethanol affects the brain’s neurons in several ways. It alters their membranes as well as their ion channels, enzymes, and receptors. Alcohol also binds directly to the receptors for acetylcholine, serotonin, GABA, and the NMDA receptors for glutamate. The sedative effects of ethanol are mediated through binding to GABA receptors and glycine receptors (alpha 1 and alpha 2 subunits). It also inhibits NMDA receptor functioning. In its role as an anti-infective, ethanol acts as an osmolyte or dehydrating agent that disrupts the osmotic balance across cell membranes. ... Ethanol is known to affect a large number of membrane proteins that participate in signaling pathways such as neurotransmitter receptors, enzymes, and ion channels, and there is extensive evidence that ethanol interacts with a variety of neurotransmitters. The major actions of ethanol involve enhancing the inhibitory effects of gamma-aminobutyric acid (GABA) at GABAa receptors and blockade of the N-methyl-D-aspartate (NMDA) subtype of glutamate, an excitatory amine acid (EAA) receptor. Animal studies indicate that the acute effects of ethanol result from competitive inhibition of glycine binding to NMDA receptor and disruption of glutamatergic neurotransmission by inhibiting the response of the NMDA receptor. Persistent glycine antagonism and attenuation of glutamatergic neurotransmission by chronic ethanol exposure results in tolerance to ethanol by enhancing EAA neurotransmission and NMDA receptor upregulation. The latter appears to involve selective increases in NMDA R2B subunit concentrations and other molecular changes in specific brain loci. The abrupt withdrawal of ethanol thus produces a hyperexcitable state that leads to the ethanol withdrawal syndrome and excitotoxic neuronal death. GABA-mediated inhibition, which normally acts to limit excitation, is eliminated during ethanol withdrawal syndrome and further intensifies this excitation. In addition, NMDA receptors function to inhibit the release of dopamine in the nucleus accumbens and mesolimbic structures, which modulate the reinforcing action of addictive xenobiotics such as ethanol. By inhibiting NMDA receptor activity, ethanol could increase dopamine release from the nucleus accumbens and ventral tegmental area and could thus create dependence. Chronic ethanol administration also results in tolerance, dependence, and an ethanol withdrawal syndrome, mediated, in part, by desensitization and or downregulation of GABAa receptors. The development of alcoholic ketoacidosis (AKA) requires that a combination of physical and physiologic events occur. The normal response to starvation and depletion of hepatic glycogen stores is for amino acids to be converted to pyruvate. Pyruvate can serve as a substrate for gluconeogenesis, be converted to acetyl-CoA, which can enter the Krebs cycle or can be utilized in various biosynthetic pathways (eg, fatty acid, ketone bodies, cholesterol, and acetylcholine) ... Ethanol metabolism generates NADH, resulting in an excess of reducing potential. This high redox state favors the conversion of pyruvate to lactate, diverting pyruvate from being a substrate for gluconeogenesis. To compensate for the lack of normal metabolic substrates, the body mobilizes fat from adipose tissue and increased fatty acid metabolism as an alternative source of energy. This response is mediated by a decrease in insulin and an increased secretion of glucagon, catecholamines, growth hormone, and cortisol. Fatty acid metabolism results in the formation of acetyl-CoA and it combines with the excess acetate that is generated from ethanol metabolism to form acetoacetate. Most of the acetoacetate is reduced to beta-hydroxybutyrate due to the excess reducing potential or high redox state of the cell. Volume depletion interferes with the renal elimination of acetoacetate and beta-hydroxybutyrate, and contributes to the acidosis. An elevated lactate concentration may result from shunting from pyruvate or

Pharmacodynamics

Alcohol produces injury to cells by dehydration and precipitation of the cytoplasm or protoplasm. This accounts for its bacteriocidal and antifungal action. When alcohol is injected in close proximity to nerve tissues, it produces neuritis and nerve degeneration (neurolysis). Ninety to 98% of ethanol that enters the body is completely oxidized. Ethanol is also used as a cosolvent to dissolve many insoluble drugs and to serve as a mild sedative in some medicinal formulations. Ethanol also binds to GABA, glycine, NMDA receptors and modulates their effects. Ethanol is also metabolised by the hepatic enzyme alcohol dehydrogenase.