Monosopt Eye Drops

Indications

• Ocular hypertension
• Open-angle glaucoma

Dosage

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

Adults: Apply 1 drop to the affected eye(s) three times daily.

Mechanism of action

Dorzolamide specifically inhibits carbonic anhydrase II, an enzyme crucial for the production of bicarbonate ions in the ciliary processes of the eye. This inhibition disrupts sodium and fluid transport, resulting in decreased secretion of aqueous humor and lower intraocular pressure. The drug exhibits a 4000-fold higher affinity for CA-II compared to CA-I, making it a potent inhibitor in the ocular context.

Pharmacodynamics

As a carbonic anhydrase inhibitor, dorzolamide effectively reduces elevated intraocular pressure in conditions like open-angle glaucoma and ocular hypertension. When used alongside topical beta-adrenergic antagonists, dorzolamide provides an additive effect in lowering intraocular pressure. The maximum reduction in intraocular pressure typically occurs approximately 2 hours after administration.

Pharmacokinetics

Dorzolamide is administered topically as eye drops, leading to systemic absorption that can cause sulfonamide-like side effects. The pharmacokinetic profile is characterized by rapid absorption and a relatively short half-life, necessitating multiple daily doses for sustained effect. It is advised to avoid use in patients with renal impairment due to the risk of metabolic acidosis.

Contra-indications

• History of sulfonamide hypersensitivity
• Severe renal impairment (creatinine clearance less than 30 mL/min)
• Hyperchloraemic acidosis

Adverse effects

• Decreased appetite
• Arthralgia
• Malaise
• Peripheral oedema
• Tremor
• Increased urinary frequency
• Dizziness
• Vertigo
• Bitter vision
• Disorders of vision
• Dry mouth
• Epistaxis
• Local reactions
• Paresthesia
• Severe cutaneous adverse reactions (SCARs)
• Angioedema
• Bronchospasm

Interactions

• Brimonidine
• Beta-blockers

Precautions

• Caution in patients with chronic corneal defects
• History of intraocular surgery
• History of renal calculi
• Low endothelial cell count
• Monitor blood count and plasma electrolyte concentrations with prolonged use

Pregnancy

Avoid-toxicity in animal studies, especially in the first trimester.

Breast-feeding

Use only if benefit outweighs risk; amount too small to be harmful.

Storage

Store at room temperature, away from light and moisture.

Formulations

• Eye drops 2% (Dorzolamide hydrochloride 20 mg/ml)

Indications

• Cerebral edema
• Elevated intracranial pressure
• Acute kidney injury
• Oliguria
• Glaucoma
• Renal function diagnostic aid

Dosage

Adults: For cerebral edema, administer 0

Mechanism of action

Mannitol elevates blood plasma osmolality, resulting in enhanced flow of water from tissues, including the brain and cerebrospinal fluid, into interstitial fluid and plasma. This action reduces cerebral edema and intracranial pressure. As a diuretic, it increases the osmolality of glomerular filtrate, leading to increased urinary excretion of water and preventing sodium and chloride reabsorption in the renal tubules. Mannitol also facilitates the urinary excretion of toxic substances and can help in assessing renal function by measuring glomerular filtration rate (GFR).

Pharmacodynamics

Mannitol is classified as an osmotic diuretic. It is chemically similar to other sugar alcohols but has a unique ability to promote diuresis by remaining unabsorbed in the renal tubules. Its use is indicated for conditions associated with increased body fluids, such as cerebral edema and glaucoma. Mannitol may be combined with other diuretics to enhance diuretic efficacy. Inhaled formulations are used in cystic fibrosis, though they may cause bronchospasm and hemoptysis.

Pharmacokinetics

Mannitol is freely filtered by the glomeruli with less than 10% tubular reabsorption, which allows for its urinary excretion rate to serve as a measurement of GFR. It does not undergo significant metabolism and is eliminated primarily through the kidneys. The onset of action occurs within 30 to 60 minutes after intravenous administration, with effects lasting for several hours. Administration may require monitoring of renal function and fluid balance.

Contra-indications

• Anuria
• Severe dehydration
• Severe renal impairment
• Intracranial bleeding

Adverse effects

• Asthenia
• Gastrointestinal disturbances
• Dry mouth
• Confusion
• Visual impairment
• Hypotension
• Electrolyte imbalances
• Pulmonary edema
• Hemoptysis (with inhalation use)
• Bronchospasm (with inhalation use)

Interactions

• Potassium-sparing diuretics may increase the risk of hyperkalemia
• Other diuretics may have additive effects
• Caution with nephrotoxic agents

Precautions

• Caution in patients with diabetes mellitus
• Caution in the elderly
• Caution in patients with gout
• Caution in patients with hepatic impairment
• Monitor renal function and electrolytes regularly
• May cause blue fluorescence of urine

Pregnancy

Manufacturer advises avoid due to potential toxicity in animal studies.

Breast-feeding

Manufacturer advises avoid due to lack of information available.

Storage

Store in a cool, dry place, away from light. Do not freeze.

Formulations

• Solution for injection
• Inhalation powder
• Oral solution

Indications

• Seborrhoeic dermatitis
• Dandruff
• Scalp psoriasis
• Bacterial infections affecting the scalp

Dosage

Children: For children, apply 3 times a week for 1 week, then apply twice weekly as needed. Refer to BNF for Children for further details.

Adults: Apply to the affected area as directed, typically 1-3 times weekly depending on the condition being treated. Refer to specific product guidelines for detailed dosing.

Mechanism of action

Benzalkonium chloride exerts its antimicrobial effect by disrupting the cell membrane of microorganisms, leading to leakage of cellular contents and ultimately cell death. This is facilitated by its cationic nature, which allows it to bind to negatively charged bacterial surfaces.

Pharmacodynamics

Benzalkonium chloride demonstrates rapid bactericidal activity, with effectiveness observed against gram-positive and gram-negative bacteria, fungi, and some viruses. Its antiseptic properties may be enhanced in the presence of moisture and are typically influenced by the concentration of the solution used.

Pharmacokinetics

Benzalkonium chloride is poorly absorbed through the skin. After topical application, it remains primarily at the site of application, where it exerts localized effects. Systemic absorption is minimal, and it is primarily eliminated through the skin and urine. However, specific pharmacokinetic data may vary based on formulation and application site.

Pregnancy

Benzalkonium chloride should be used with caution during pregnancy. Refer to specific guidelines or consult a healthcare professional.

Breast-feeding

Benzalkonium chloride should be used with caution while breastfeeding. Refer to specific guidelines or consult a healthcare professional.

Storage

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

Formulations

• Shampoo
• Soap or detergent
• Topical solution

Indications

• Disinfection of surfaces
• Antiseptic for skin
• Preservative in pharmaceuticals
• Treatment of minor cuts and abrasions

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations in pediatric populations.

Adults: Refer to the BNF for specific formulations and concentrations as doses may vary based on the application and preparation.

Mechanism of action

The bactericidal action of benzalkonium chloride is believed to result from the disruption of intermolecular interactions, which leads to the dissociation of cellular membrane lipid bilayers in bacteria. This disruption compromises cellular permeability, causing leakage of vital cellular contents. Moreover, the agent can deactivate important molecular complexes such as enzymes that regulate various respiratory and metabolic activities within the cells. Cationic surfactants like benzalkonium chloride can thus effectively disrupt critical intermolecular interactions and tertiary structures in biochemical systems, impairing bacterial function.

Pharmacodynamics

Benzalkonium chloride is classified as a biocidal agent with a relatively long duration of action. It exhibits a spectrum of activity against various microorganisms, including bacteria, certain viruses, fungi, and protozoa; however, it is ineffective against bacterial spores. The agent tends to demonstrate greater efficacy against gram-positive bacteria compared to gram-negative ones. The mode of action can be bacteriostatic (preventing growth) or bactericidal (killing bacteria), depending on its concentration. The activity of benzalkonium chloride is generally stable across different pH levels but is enhanced at elevated temperatures and with extended exposure.

Pharmacokinetics

The pharmacokinetic properties of benzalkonium chloride, including absorption, distribution, metabolism, and excretion, are not fully characterized. Its topical application limits systemic exposure, and it primarily exerts localized effects at the site of application. The duration of action and efficacy may be influenced by the formulation and concentration used.

Pregnancy

Benzalkonium chloride is generally considered safe for use during pregnancy when applied topically, but systemic absorption should be minimized. Always consult a healthcare provider for use during pregnancy.

Breast-feeding

Benzalkonium chloride is considered safe for topical application during breastfeeding, but care should be taken to avoid exposure to the infant. Consultation with a healthcare provider is recommended.

Storage

Store at room temperature, away from moisture and heat. Keep in a tightly closed container, protected from light.

Formulations

• Topical solution
• Disinfectant wipes
• Liquid antiseptics

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

Dosage

Children: Refer to specific guidelines for pediatric dosing; consult the BNF for Children for accurate dosage information.

Adults: Refer to specific guidelines for use; dosage may vary based on the context of use.

Mechanism of action

Hydroxide ions act primarily as bases, neutralizing acids to form water and salts. They participate in various biochemical pathways, including selenium metabolism and the degradation of reactive oxygen species. Hydroxide can influence enzyme activity and stability by altering the pH of the environment, thereby affecting metabolic reactions.

Pharmacodynamics

Hydroxide ions can impact biological processes by changing the local pH, which influences enzyme activity, ion transport, and the solubility of other compounds. Their ability to neutralize acids can help regulate physiological pH, contributing to homeostasis in living organisms.

Pharmacokinetics

As an inorganic ion, hydroxide does not undergo traditional pharmacokinetic processes like absorption, distribution, metabolism, or excretion. Instead, it is rapidly equilibrated in biological fluids and participates in acid-base reactions, having immediate effects on the local environment.

Pregnancy

There is limited information regarding the use of hydroxide during pregnancy. Consult a healthcare professional for advice.

Breast-feeding

Limited data is available on the excretion of hydroxide in breast milk. Consult a healthcare professional before use.

Storage

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

Indications

• Hypovolemia
• Shock
• Fluid resuscitation

Dosage

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

Adults: Refer to the BNF for appropriate dosing guidelines depending on the clinical scenario and formulation used.

Mechanism of action

Hydroxyethyl starch works by increasing oncotic pressure in the blood, thereby drawing fluid into the vascular space. This helps to expand blood volume and improve circulation. The mechanism involves its ability to mimic natural plasma proteins, resulting in an effective volume expansion.

Pharmacodynamics

Hydroxyethyl starch acts as a colloid, helping to maintain intravascular volume. It is metabolized in the body, with its effects depending on the degree of substitution and molecular weight. The drug's colloidal properties facilitate the retention of fluid within the vascular system, which is crucial in treating conditions such as hypovolemia and shock.

Pharmacokinetics

Hydroxyethyl starch is administered intravenously and is distributed throughout the vascular system. It is gradually metabolized by the reticuloendothelial system, primarily the liver and spleen. The elimination half-life varies depending on the molecular weight and concentration of the formulation used. Higher molecular weight formulations tend to persist longer in circulation.

Pregnancy

Not established. Use with caution and only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Use with caution. Limited data available.

Storage

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

Indications

• Fever management
• Assessment of the immune response
• Monitoring of inflammatory processes

Dosage

Children: Refer to specific guidelines based on the indication, as dosage can vary widely depending on the source of the pyrogen and the clinical context.

Adults: Refer to specific guidelines based on the indication, as dosage can vary widely depending on the source of the pyrogen and the clinical context.

Mechanism of action

Pyrogens typically act by stimulating the release of pro-inflammatory cytokines, such as interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha), from immune cells. These cytokines then act on the hypothalamus to increase the set point of body temperature, leading to fever. This elevation in temperature is thought to enhance the activity of immune cells and inhibit pathogen growth.

Pharmacodynamics

The pharmacodynamics of pyrogens involve their ability to activate various immune pathways, including the activation of macrophages and other immune cells that produce inflammatory mediators. This process results in systemic effects such as fever, increased heart rate, and changes in metabolism. Fever serves as a defense mechanism, enhancing the immune response while also creating a less favorable environment for pathogens.

Pharmacokinetics

Pyrogens are generally not absorbed through the gastrointestinal tract, as they are usually introduced via injections or generated as a response to infection. Their effects are immediate, with the onset of fever typically occurring within hours after exposure. The duration of action varies depending on the source and type of pyrogen, as well as the individual’s immune response. The elimination of endogenous pyrogens is mediated by the immune system, while exogenous pyrogens may be cleared by the liver or other organs.

Pregnancy

Safety during pregnancy has not been established. Caution is advised.

Breast-feeding

Safety during breastfeeding has not been established. Caution is advised.

Storage

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

Mechanism of action

Elevated intraocular pressure is a characteristic manifestation of ocular hypertension or open-angle glaucoma. The level of intraocular pressure (IOP) is governed by the balance between the production of aqueous humour (by ocular ciliary processes) and its outflow from the anterior segment of the eye via trabecular (conventional) or uveoscleral (unconventional) pathways. When there is an increase in the resistance to the trabecular outflow of aqueous humour, the intraocular pressure is elevated. Subsequently, optic nerve damage can occur from blood flow restrictions and mechanical distortion of ocular structures. Optic nerve damage can further result in optic disc cupping and progressive visual field loss (and blindness in some cases). Carbonic anhydrase (CA) is a ubiquitous enzyme that catalyzes the reversible hydration of carbon dioxide to bicarbonate ions and dehydration of carbonic acid. In the ocular ciliary processes, the local production of bicarbonate by CAs promotes sodium and fluid transport. CA-II is a key isoenzyme found primarily in red blood cells (RBCs) that regulates aqueous humour production. Dorzolamide is a highly specific CA-II inhibitor, where it displays a 4000-fold higher affinity for carbonic anhydrase II than carbonic anhydrase I. The inhibition of CA-II in the ciliary process disrupts the formation of bicarbonate ions and reduces sodium and fluid transport, which leads to decreased aqueous humour secretion and reduced intraocular pressure.

Pharmacodynamics

Dorzolamide is a carbonic anhydrase inhibitor that reduces elevated intraocular pressure in open-angle glaucoma or ocular hypertension. When used in combination with topic beta-adrenergic antagonists, dorzolamide has an additive effect of lowering intraocular pressure. The peak ocular hypotensive effect of dorzolamide is observed at about 2 hours following ophthalmic administration.

Mechanism of action

Mannitol is an osmotic diuretic that is metabolically inert in humans and occurs naturally, as a sugar or sugar alcohol, in fruits and vegetables. Mannitol elevates blood plasma osmolality, resulting in enhanced flow of water from tissues, including the brain and cerebrospinal fluid, into interstitial fluid and plasma. As a result, cerebral edema, elevated intracranial pressure, and cerebrospinal fluid volume and pressure may be reduced. As a diurectic mannitol induces diuresis because it is not reabsorbed in the renal tubule, thereby increasing the osmolality of the glomerular filtrate, facilitating excretion of water, and inhibiting the renal tubular reabsorption of sodium, chloride, and other solutes. Mannitol promotes the urinary excretion of toxic materials and protects against nephrotoxicity by preventing the concentration of toxic substances in the tubular fluid. As an Antiglaucoma agent mannitol levates blood plasma osmolarity, resulting in enhanced flow of water from the eye into plasma and a consequent reduction in intraocular pressure. As a renal function diagnostic aid mannitol is freely filtered by the glomeruli with less than 10% tubular reabsorption. Therefore, its urinary excretion rate may serve as a measurement of glomerular filtration rate (GFR). The exact mechanism of action of inhaled mannitol in the symptomatic maintenance treatment of cystic fibrosis remains unclear. It is hypothesized that mannitol produces an osmotic gradient across the airway epithelium that draws fluid into the extracellular space and alters the properties of the airway surface mucus layer, allowing easier mucociliary clearance. MANNITOL IS.../USED/ IN PROPHYLAXIS OF ACUTE RENAL FAILURE. IT IS USED FOR THIS PURPOSE IN CONDITIONS AS DIVERSE AS CARDIOVASCULAR OPERATIONS, SEVERE TRAUMATIC INJURY, OPERATIONS IN THE PRESENCE OF SEVERE JAUNDICE, AND MGMNT OF HEMOLYTIC TRANSFUSION REACTIONS. IN EACH OF THESE CONDITIONS, A PRECIPITOUS FALL IN THE FLOW OF URINE MAY BE ANTICIPATED EITHER AS THE RESULT OF AN ACUTELY REDUCED FILTRATION RATE OR FROM ACUTE CHANGES IN TUBULAR PERMEABILITY. THE LATTER MAY BE CONSEQUENCE OF THE PRESENCE OF NOXIOUS AGENT WITHIN THE TUBULAR FLUID IN EXCESSIVELY HIGH CONCN, IN SOME INSTANCES SUFFICIENT TO RESULT IN ACTUAL PRECIPITATION. IN THESE SITUATIONS, MANNITOL EXERTS OSMOTIC EFFECT WITHIN THE TUBULAR FLUID, INHIBITS WATER REABSORPTION, & MAINTAINS THE RATE OF URINE FLOW. ...CONCN OF TOXIC AGENT WITHIN TUBULAR FLUID DOES NOT REACH EXCESSIVELY HIGH LEVELS THAT OTHERWISE WOULD HAVE BEEN ACHIEVED BY MORE COMPLETE REABSORPTION OF WATER. ...EVEN THOUGH /GLOMERULAR/ FILTRATION RATE IS REDUCED, MANNITOL IS STILL FILTERED @ GLOMERULUS. THE TUBULAR IMPERMEABILITY TO MANNITOL IS NOT ALTERED BY ACUTE RENAL ISCHEMIA OF SHORT DURATION. HENCE, THE MANNITOL THAT IS FILTERED IS ALSO EXCRETED IN THE VOIDED URINE. UNREABSORBED SOLUTE LIMITS BACK DIFFUSION OF WATER. ...URINE VOL CAN BE MAINTAINED EVEN IN PRESENCE OF DECR GLOMERULAR FILTRATION.

Pharmacodynamics

Chemically, mannitol is an alcohol and a sugar, or a polyol; it is similar to xylitol or sorbitol. However, mannitol has a tendency to lose a hydrogen ion in aqueous solutions, which causes the solution to become acidic. For this reason, it is not uncommon to add a substance to adjust its pH, such as sodium bicarbonate. Mannitol is commonly used to increase urine production (diuretic). It is also used to treat or prevent medical conditions that are caused by an increase in body fluids/water (e.g., cerebral edema, glaucoma, kidney failure). Mannitol is frequently given along with other diuretics (e.g., furosemide, chlorothiazide) and/or IV fluid replacement. Inhaled mannitol has the possibility to cause bronchospasm and hemoptysis; the occurrence of either should lead to discontinuation of inhaled mannitol.

Mechanism of action

Although not entirely elucidated, the bactericidal action of benzalkonium chloride is believed to be due to the disruption of intermolecular interactions. Such disruption can cause the dissociation of cellular membrane lipid bilayers of bacteria, resulting in compromised cellular permeability control and the leakage of important cellular contents. Additionally, other important molecular complexes like enzymes which control the maintenance of a great range of respiratory and metabolic cellular activities, are also susceptible to such deactivation. Consequently, a variety of critical intermolecular interactions and tertiary structures in very highly specific biochemical systems that allow bacterial agents to function normally can be readily disrupted or deactivated by cationic surfactants like benzalkonium chloride..

Pharmacodynamics

Benzalkonium chloride solutions are generally categorized as biocidal agents with relative long durations of action. Their spectrum of activity has been demonstrated against bacteria, to some viruses, fungi, and protozoa, although bacterial spores are treated as being resistant to the agent. Additionally, the agent generally shows more activity against gram-positive than gram-negative bacteria. Finally, solutions of benzalkonium chloride are bacteriostatic or bactericidal based on their concentration. Bacteriostatic agents act to prevent further growth of bacterial organisms that are present while bactericidal agents function to kill bacteria that are present. In general, the activity of the agent is not largely affected by pH, but such activity does increase substantially at higher temperatures and prolonged exposure times.