Cantab 8mg Tablet

Indications

• Dry eye conditions
• Keratoconjunctivitis sicca
• Unstable tear film

Dosage

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

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

Mechanism of action

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

Pharmacodynamics

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

Pharmacokinetics

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

Adverse effects

• Transient blurred vision
• Eye irritation
• Allergic reactions

Precautions

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

Pregnancy

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

Breast-feeding

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

Storage

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

Formulations

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

Indications

• Hypertension
• Heart failure
• Left ventricular dysfunction post-myocardial infarction

Dosage

Children: For children aged 1 to 17 years, the dose is based on body weight. The recommended starting dose is 0.05 to 0.1 mg/kg once daily, with a maximum dose of 0.4 mg/kg or 32 mg, whichever is lower.

Adults: The typical adult starting dose for hypertension is 8 mg once daily, which may be increased to a maximum of 32 mg once daily based on blood pressure response.

Mechanism of action

Candesartan selectively antagonizes the type I angiotensin II receptor (AT1), preventing angiotensin II from exerting its vasoconstrictive and aldosterone-secreting effects. This inhibition allows for vasodilation and decreased aldosterone release, promoting sodium excretion and lowering blood pressure. Candesartan does not affect the degradation of bradykinin, thus minimizing the common side effects associated with ACE inhibitors, such as cough and angioedema.

Pharmacodynamics

Candesartan effectively reduces systemic vascular resistance and lowers blood pressure, which can lead to a decrease in myocardial oxygen demand. Its long duration of action allows for once-daily dosing, and it has shown efficacy in both monotherapy and in combination with other antihypertensive agents. It also demonstrates cardioprotective effects, making it beneficial in the management of heart failure.

Pharmacokinetics

Candesartan is well-absorbed following oral administration, with peak plasma concentrations occurring approximately 1 to 3 hours after dosing. It has a bioavailability of around 15% due to extensive first-pass metabolism. Candesartan is primarily excreted via the kidneys, with a half-life of about 9 hours. The presence of food does not significantly affect its absorption.

Contra-indications

• Hypersensitivity to candesartan or any of its excipients
• Severe hepatic impairment
• Pregnancy

Adverse effects

• Dizziness
• Fatigue
• Hypotension
• Hyperkalemia
• Renal impairment
• Angioedema

Interactions

• Other antihypertensive agents may increase the hypotensive effect
• Potassium-sparing diuretics or potassium supplements may increase the risk of hyperkalemia
• Non-steroidal anti-inflammatory drugs (NSAIDs) may reduce the antihypertensive effect and increase the risk of renal impairment

Precautions

• Caution in patients with renal artery stenosis
• Monitor renal function, especially in patients with pre-existing renal impairment
• Caution in patients with aortic stenosis or hypertrophic cardiomyopathy
• Use with caution in patients with a history of angioedema

Pregnancy

Candesartan is contraindicated in pregnancy due to potential harm to the fetus, particularly in the second and third trimesters.

Breast-feeding

Candesartan is excreted in breast milk, and caution should be exercised when administering to breastfeeding women.

Storage

Store below 25°C in a dry place, protect from light.

Formulations

• Tablets: 4 mg, 8 mg, 16 mg, 32 mg

Indications

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

Dosage

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

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

Mechanism of action

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

Pharmacodynamics

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

Pharmacokinetics

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

Adverse effects

• Gastrointestinal discomfort
• Bloating
• Diarrhea

Precautions

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

Pregnancy

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

Breast-feeding

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

Storage

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

Formulations

• Powder
• Tablet
• Capsule
• Suspension

Indications

• Constipation
• Dietary fiber supplementation
• Irritable bowel syndrome
• Diverticular disease
• Weight management

Dosage

Children: Refer to appropriate guidelines for specific dosage; generally taken with adequate fluid intake.

Adults: Refer to appropriate guidelines for specific dosage; generally taken with adequate fluid intake.

Mechanism of action

Cellulose acts primarily as a bulk-forming laxative. It absorbs water in the intestines, which increases stool bulk and stimulates peristalsis, thus facilitating bowel movements. Additionally, cellulose is not digestible by human enzymes, leading to fermentation by gut bacteria, which may enhance gut health and alter gut microbiota composition.

Pharmacodynamics

Cellulose increases stool weight and frequency of bowel movements. It works by retaining water in the intestines, leading to softer stools and improved passage through the gastrointestinal tract. The bulking effect of cellulose can help alleviate constipation and promote overall digestive health. It may also play a role in cholesterol reduction and glycemic control through its effects on digestion and absorption of nutrients.

Pharmacokinetics

Cellulose is not absorbed into the bloodstream due to its indigestible nature. Instead, it passes through the gastrointestinal tract, where it adds bulk to the stool. Its fermentation by colonic bacteria produces short-chain fatty acids, which may have beneficial effects on colon health. The onset of action for cellulose as a laxative can vary but is generally within 24 to 72 hours after ingestion.

Adverse effects

• Bloating
• Flatulence
• Diarrhea
• Abdominal discomfort

Precautions

• Use with caution in patients with a history of gastrointestinal disorders.
• Monitor for potential allergic reactions in sensitive individuals.

Pregnancy

Cellulose is generally considered safe during pregnancy as it is a non-toxic, indigestible fiber.

Breast-feeding

Cellulose is also considered safe during breastfeeding; it is excreted in breast milk in negligible amounts.

Storage

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

Formulations

• Powder
• Capsules
• Tablets
• Granules

Indications

• Hypertension
• Heart failure
• Certain cardiovascular conditions

Dosage

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

Adults: Refer to the BNF for specific dosing information.

Mechanism of action

Cilexetil is converted to its active form, which blocks the action of angiotensin II, a potent vasoconstrictor involved in blood pressure regulation. By inhibiting the angiotensin II receptor, cilexetil promotes vasodilation and decreases peripheral vascular resistance, leading to a reduction in blood pressure.

Pharmacodynamics

Cilexetil's antihypertensive effects are realized through its antagonistic action on the angiotensin II receptors, which results in decreased levels of aldosterone, inhibition of vasoconstriction, and reduced secretion of antidiuretic hormone. The overall pharmacodynamic profile contributes to improved cardiac output and reduced workload on the heart.

Pharmacokinetics

Cilexetil is well-absorbed following oral administration and undergoes extensive first-pass metabolism to its active metabolite. The pharmacokinetic profile indicates a moderate half-life, allowing for once-daily dosing. The distribution of cilexetil is extensive, with high protein binding rates, primarily to serum albumin. Metabolism occurs mainly in the liver, and renal excretion is the primary route for elimination of the drug and its metabolites.

Pregnancy

There is limited data on the use of cilexetil in pregnancy. Caution is advised.

Breast-feeding

It is not known whether cilexetil is excreted in human milk. Caution is recommended.

Storage

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

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

• Used as an excipient in pharmaceutical formulations
• Improves solubility and stability of active ingredients
• Facilitates drug absorption

Dosage

Children: Refer to specific product guidelines as hydroxypropyl is typically used as an excipient and not dosed independently.

Adults: Refer to specific product guidelines as hydroxypropyl is typically used as an excipient and not dosed independently.

Mechanism of action

Hydroxypropyl functions primarily as a solubilizing agent, which aids in the dissolution of poorly soluble drugs. It interacts with water and other solvents to improve the dispersion of pharmaceutical compounds, thereby enhancing their bioavailability. Hydroxypropyl may also facilitate the permeability of drug molecules through biological membranes, contributing to their overall efficacy.

Pharmacodynamics

The pharmacodynamics of hydroxypropyl relate to its role in improving the physicochemical properties of drug formulations. By increasing solubility and stability, hydroxypropyl can enhance the absorption of drugs administered via various routes, including oral and topical. Its non-toxic nature allows for safe incorporation into formulations, making it suitable for a wide range of applications.

Pharmacokinetics

The pharmacokinetics of hydroxypropyl have not been extensively studied as it primarily acts as an excipient rather than an active pharmaceutical ingredient. When used in formulations, it is typically not absorbed into systemic circulation in significant amounts, thereby minimizing potential systemic effects. Hydroxypropyl is generally regarded as safe when used in appropriate amounts in drug formulations.

Pregnancy

Hydroxypropyl is not classified for use during pregnancy, and its safety has not been established. Caution is advised.

Breast-feeding

There is limited information on the excretion of hydroxypropyl in human milk. Caution is advised when administering to breastfeeding women.

Storage

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

Indications

• Lactose intolerance
• As a filler or excipient in pharmaceutical formulations

Dosage

Children: Refer to the BNF for Children for specific dosing information based on age and clinical context.

Adults: Refer to the BNF for specific dosing information based on clinical context.

Mechanism of action

Lactose is metabolized in the intestine by the enzyme lactase into its constituent monosaccharides, glucose and galactose. In individuals with lactase deficiency, unabsorbed lactose passes into the colon, where it is fermented by bacteria, leading to gas production and osmotic effects that contribute to diarrhea.

Pharmacodynamics

The pharmacodynamics of lactose are primarily related to its effects on gastrointestinal function. In healthy individuals, lactose is effectively broken down into glucose and galactose, which are absorbed and utilized for energy. In individuals with lactose intolerance, the unabsorbed lactose can cause osmotic diarrhea and colonic fermentation, leading to discomfort and symptoms associated with lactose intolerance.

Pharmacokinetics

Lactose is not absorbed in the gastrointestinal tract until it is hydrolyzed into glucose and galactose by lactase. The absorption of glucose and galactose occurs in the small intestine. The half-life is not applicable as lactose is not typically administered as a medication but is rather ingested as a natural component of food. Its metabolism primarily occurs in the intestine.

Adverse effects

• Bloating
• Diarrhea
• Abdominal pain
• Flatulence

Precautions

• Use with caution in patients with lactose intolerance.
• Consider potential for gastrointestinal upset in sensitive individuals.

Pregnancy

Lactose is generally considered safe for use during pregnancy. However, consult a healthcare professional for individual advice.

Breast-feeding

Lactose is safe to use while breastfeeding, as it is a natural sugar present in breast milk.

Storage

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

Formulations

• Powder
• Granules
• Tablets
• Syrup

Indications

• Constipation
• Bowel preparation for surgical procedures
• Bowel cleansing for diagnostic procedures

Dosage

Children: For children, the dosage of macrogols varies based on age and weight. Generally, it is advised to refer to the BNF for Children for specific dosing guidelines.

Adults: The usual adult dose for constipation is 8.4 grams of macrogol in a glass of water daily. For bowel preparation, the dosing regimen may vary depending on the procedure and should be followed as directed by healthcare professionals.

Mechanism of action

Macrogols exert their laxative effect by increasing the osmotic pressure in the intestinal lumen, which leads to enhanced water retention in the stool. This results in softer stools and stimulates peristalsis, promoting bowel movements. The mechanism involves the prevention of water reabsorption in the colon, thereby increasing stool volume and frequency of defecation.

Pharmacodynamics

The pharmacodynamics of macrogols involve their ability to attract and retain water in the gastrointestinal tract. This osmotic effect leads to increased stool water content, which softens the stool and decreases transit time. As a result, macrogols are effective in alleviating constipation and are also used for bowel cleansing prior to various medical procedures.

Pharmacokinetics

Macrogols are not absorbed systemically; they remain in the gastrointestinal tract and exert their effects locally. Due to their high molecular weight, they are not significantly broken down by intestinal enzymes. The onset of action typically occurs within 24 to 48 hours after administration, making them suitable for both acute and chronic constipation management.

Pregnancy

Macrogols are not absorbed systemically and are generally considered safe for use during pregnancy.

Breast-feeding

Macrogols are not absorbed systemically and are considered safe for use while breastfeeding.

Storage

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

Formulations

• powder for oral solution
• oral solution

Indications

• Nutritional support
• Source of carbohydrates
• Dietary fiber source
• Animal feed

Dosage

Children: As with adults, there are no specific dosing recommendations for maize for children. It can be introduced into the diet in age-appropriate forms and quantities, keeping in mind the overall dietary balance.

Adults: There are no specific dosing recommendations for maize as it is typically consumed as part of a balanced diet. It can be included in daily meals in various forms such as whole kernels, flour, or as part of dishes.

Mechanism of action

Maize primarily acts as a source of energy due to its high carbohydrate content. The complex carbohydrates in maize are broken down into glucose, which is then utilized by the body for energy production. It also contributes to dietary fiber intake, which can aid in digestive health and regulation of blood sugar levels.

Pharmacodynamics

The consumption of maize influences blood glucose and insulin levels due to its carbohydrate content. It has a relatively low glycemic index when consumed in whole form, which can help in managing blood sugar levels. The dietary fiber present in maize can also promote satiety and aid in weight management.

Pharmacokinetics

The digestion of maize begins in the mouth with salivary amylase breaking down starches into simpler sugars. In the stomach and small intestine, enzymes further break down these carbohydrates. The resultant glucose is absorbed into the bloodstream, where it is transported to cells for energy production. The absorption rate can vary based on the form of maize consumed (e.g., whole kernels versus processed forms).

Pregnancy

Maize is generally considered safe for consumption during pregnancy as it is a staple food and provides essential nutrients.

Breast-feeding

Maize is safe to consume while breastfeeding and can provide important nutrients to both the mother and the infant.

Storage

Store in a cool, dry place, away from moisture and pests. Properly sealed containers can help prolong shelf life.

Formulations

• Whole maize grains
• Maize flour (cornmeal)
• Maize starch
• Maize oil

Mechanism of action

Oxides do not have a single mechanism of action as they are a broad category of compounds. However, in general, metal oxides can exhibit catalytic properties, while non-metal oxides may participate in biochemical reactions by forming acids or bases upon dissolution in water.

Pharmacodynamics

The pharmacodynamics of oxides depend on the specific type of oxide and its interaction with biological systems. For instance, metal oxides may have antimicrobial properties, while certain non-metal oxides can influence metabolic pathways through their acid-base chemistry. The effects vary widely, necessitating specific studies for each oxide's role in therapeutic contexts.

Pharmacokinetics

The pharmacokinetics of oxides are also variable. Many metal oxides are poorly soluble and thus have limited absorption when ingested. Non-metal oxides, such as carbon dioxide, can be readily absorbed and utilized in metabolic processes. The distribution, metabolism, and excretion of oxides depend on their chemical form and the biological system in which they are involved.

Pregnancy

Not applicable as oxide is not a drug but a class of chemical compounds.

Breast-feeding

Not applicable as oxide is not a drug but a class of chemical compounds.

Storage

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

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

• Nutritional supplementation
• Energy source in enteral nutrition
• Excipient in pharmaceutical formulations

Dosage

Children: Refer to specific guidelines or product inserts for dosing information, as it can vary based on the context of use.

Adults: Refer to specific guidelines or product inserts for dosing information, as it can vary based on the context of use.

Mechanism of action

Starch is broken down into glucose units by enzymes such as amylase during digestion. The glucose is then absorbed in the intestines and utilized for energy production in the body's cells. This pathway involves hydrolysis of the glycosidic bonds, converting starch into simpler sugars.

Pharmacodynamics

Starch primarily serves as an energy source. Its digestion and absorption lead to an increase in blood glucose levels, which provides energy for metabolic processes. In this context, it plays a crucial role in maintaining energy homeostasis in the body.

Pharmacokinetics

Starch is not absorbed in its polymeric form; it must first be enzymatically hydrolyzed into simpler sugars such as maltose and glucose. The digestion and absorption of starch occur predominantly in the small intestine, with glucose being readily absorbed into the bloodstream. The rate of absorption can vary depending on the type of starch and its physical form.

Adverse effects

• Allergic reactions
• Gastrointestinal discomfort
• Diarrhea
• Constipation

Precautions

• Use with caution in individuals with known allergies to starch or starch derivatives
• Monitor for gastrointestinal symptoms in patients with a history of digestive disorders

Pregnancy

Starch is generally considered safe for use during pregnancy. However, it should be consumed in moderation as part of a balanced diet.

Breast-feeding

Starch is deemed safe for nursing mothers when used in moderation as part of a balanced diet.

Storage

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

Formulations

• Powder
• Granules
• Tablets
• Suspensions

Mechanism of action

Although these agents /angiotensin II receptor antagonists/ are similar to ACE inhibitors in that they decrease the effects of angiotensin II, rather than decreasing the formation of angiotensin II, drugs antagonize angiotensin II at the type I angiotensin receptor. This allows the drugs to inhibit the vasoconstrictive and aldosterone promoting effects of angiotensin II without interfering with bradykinin degradation, significantly reducing the adverse effects of cough and angioedema seen with ACE inhibitor therapy. ... /Angiotensin II receptor antagonists/ Angiotensin II is formed from angiotensin I in a reaction catalyzed by angiotensin-converting enzyme (ACE, kininase II). Angiotensin II is the principal pressor agent of the renin-angiotensin system, with effects that include vasoconstriction, stimulation of synthesis and release of aldosterone, cardiac stimulation, and renal reabsorption of sodium. Candesartan blocks the vasoconstrictor and aldosterone-secreting effects of angiotensin II by selectively blocking the binding of angiotensin II to the AT1 receptor in many tissues, such as vascular smooth muscle and the adrenal gland. Its action is, therefore, independent of the pathways for angiotensin II synthesis. There is also an AT2 receptor found in many tissues, but AT2 is not known to be associated with cardiovascular homeostasis. Candesartan has much greater affinity (>10,000-fold) for the ATI receptor than for the AT2 receptor. Blockade of the renin-angiotensin system with ACE inhibitors, which inhibit the biosynthesis of angiotensin II from angiotensin I, is widely used in the treatment of hypertension. ACE inhibitors also inhibit the degradation of bradykinin, a reaction also catalyzed by ACE. Because candesartan does not inhibit ACE (kininase II), it does not affect the response to bradykinin. Whether this difference has clinical relevance is not yet known. Candesartan does not bind to or block other hormone receptors or ion channels known to be important in cardiovascular regulation. Blockade of the angiotensin II receptor inhibits the negative regulatory feedback of angiotensin II on renin secretion, but the resulting increased plasma renin activity and angiotensin II circulating levels do not overcome the effect of candesartan on blood pressure.

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.

Mechanism of action

Ethylene glycol is metabolized by alcohol dehydrogenase to glycoaldehyde, which is then metabolized to glycolic, glyoxylic, and oxalic acids. These acids, along with excess lactic acid are responsible for the anion gap metabolic acidosis. Oxalic acid readily precipitates with calcium to form insoluble calcium oxalate crystals. Tissue injury is caused by widespread deposition of oxalate crystals and the toxic effects of glycolic and glyoxylic acids.