CEFLIN-200

Indications

• Bacterial infections due to sensitive Gram-positive and Gram-negative bacteria
• Surgical prophylaxis
• Haemophilus influenzae epiglottitis
• Acute infections
• Meningitis (emergency treatment)
• Uncomplicated gonorrhoea
• Disseminated gonococcal infection

Dosage

Children: In children aged 1 month to 11 years

Adults: For adults, the typical dosage is 1 g every 12 hours for severe infections, or 400 mg for a single dose in cases of uncomplicated gonorrhoea.

Mechanism of action

Cefixime binds to penicillin-binding proteins (PBPs) located in the bacterial cell wall. This binding inhibits the transpeptidase activity essential for peptidoglycan cross-linking, thereby disrupting cell wall synthesis and integrity, which ultimately leads to bacterial cell lysis, especially in rapidly growing bacteria.

Pharmacodynamics

Cefixime exhibits bactericidal activity by preventing the final stages of bacterial cell wall synthesis. It is stable against certain beta-lactamases, making it effective against some resistant bacterial strains. The drug can cause hypersensitivity reactions and is associated with a risk of Clostridium difficile-associated diarrhea. It may also lead to a decrease in prothrombin activity, necessitating caution in susceptible populations.

Pharmacokinetics

Cefixime is well-absorbed after oral administration, with a bioavailability of approximately 40-50%. Peak plasma concentrations occur within 2-6 hours post-dose. It is widely distributed in body tissues and fluids, including urine. The drug is primarily eliminated via the kidneys, with dose adjustments required in patients with renal impairment. Cefixime has a half-life of about 3-4 hours, necessitating multiple doses for sustained therapeutic effect.

Contra-indications

• Hypersensitivity to cefixime or other cephalosporins
• Severe renal impairment

Adverse effects

• Acute kidney injury
• Arthralgia
• Drug fever
• Dyspepsia
• Dyspnoea
• Edema
• Flatulence
• Genital pruritus
• Hypereosinophilia
• Jaundice
• Serum sickness-like reaction
• Thrombocytosis

Interactions

• Probenecid may increase cefixime levels
• Cephalosporins may interact with anticoagulants and increase bleeding risk
• Certain antibiotics may have additive effects

Precautions

• Caution in patients with a history of gastrointestinal disease, particularly colitis
• Monitor renal function in patients with renal impairment
• Use with caution in patients on dialysis

Pregnancy

Not known to be harmful.

Breast-feeding

Present in milk in low concentrations; use with caution.

Storage

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

Formulations

• Oral tablets
• Injection (intravenous and intramuscular)

Indications

• Skin disinfection
• Preparation of skin before injections
• Cleansing minor wounds

Dosage

Children: Apply to the skin as required; consult product literature for specific guidance.

Adults: Apply to the skin as required for disinfection.

Mechanism of action

Alcohol exerts its antiseptic effect by denaturing proteins, disrupting cell membranes, and dehydrating microbial cells, leading to cell lysis and death.

Pharmacodynamics

Alcohol has broad-spectrum antimicrobial activity, effective against bacteria, fungi, and viruses. Its efficacy is influenced by concentration, with higher concentrations generally being more effective.

Pharmacokinetics

Alcohol is rapidly absorbed through the skin and mucous membranes. It is metabolized primarily in the liver, with a half-life that varies based on the individual's metabolic rate and the amount consumed.

Contra-indications

• Concomitant use with lithium
• Regular use in neonates
• Patients with severe burns when diathermy has been preceded by application of alcoholic skin disinfectants

Adverse effects

• Eye erythema
• Punctate keratitis
• Cytotoxicity
• Eye discolouration

Interactions

• Increases risk of visual disturbances with antiepileptics
• Increases concentration with methylphenidate
• Increases risk of facial flushing and skin irritation with topical pimecrolimus
• Increases concentration with retinoids
• Increases concentration with acitretin
• Increases risk of facial flushing and skin irritation with topical tacrolimus
• Decreases antidiuretic effect with vasopressin

Precautions

• Avoid regular application to inflamed or broken skin or mucosa
• Avoid broken skin
• Flammable

Pregnancy

Sufficient iodine may be absorbed to affect the fetal thyroid in the second and third trimester.

Breast-feeding

Avoid regular or excessive use.

Storage

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

Formulations

• Betadine 2.5% dry powder spray
• Industrial methylated spirit
• Povidone-Iodine 25 mg per 1 gram

Indications

• Dry eye syndrome
• Ocular surface disorders
• Pharmaceutical formulations requiring viscosity enhancement
• Lubricating eye drops
• Thickening agent in food and cosmetic products

Dosage

Children: Refer to specific product guidelines for pediatric dosing as it varies based on formulation and intended use.

Adults: Refer to specific product guidelines for dosing instructions as it varies based on formulation and intended use.

Mechanism of action

Carmelose works by increasing the viscosity of solutions, which helps to prolong the contact time of drugs with the mucosal surfaces. It forms a gel-like consistency when hydrated, which can enhance the delivery and absorption of active pharmaceutical ingredients. Additionally, its hydrophilic nature allows it to retain water, thereby providing lubrication and hydration to tissues.

Pharmacodynamics

Carmelose does not produce systemic pharmacological effects as it primarily acts locally at the site of application. Its viscosity-increasing properties help in enhancing the stability of formulations and can aid in the retention of moisture, which is particularly beneficial in lubricating and hydrating products. In ophthalmic applications, carmelose alleviates symptoms of dry eyes by acting as an artificial tear substitute, providing relief by maintaining hydration on the ocular surface.

Pharmacokinetics

Carmelose is poorly absorbed when administered orally or topically, which means its effects are largely localized to the site of application. It is not metabolized significantly in the body and is excreted unchanged. Due to its hydrophilic nature, it can swell and retain water, which helps to sustain its effects in formulations. The pharmacokinetic profile is characterized by its minimal absorption and extensive local action.

Pregnancy

Carmelose is generally considered safe for use during pregnancy as it is not systemically absorbed and is used primarily as a lubricant or thickening agent.

Breast-feeding

Carmelose is also regarded as safe during breastfeeding since it is not absorbed into the systemic circulation.

Storage

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

Formulations

• Eye drops
• Ophthalmic gel
• Oral 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

• Allergic rhinitis
• Common cold
• Sinusitis
• Seasonal allergies
• Nasal congestion

Dosage

Children: Refer to specific product formulations and BNF for Children for appropriate dosing in children, as it varies based on age and weight.

Adults: Refer to specific product formulations for dosing instructions, as they can vary by manufacturer and formulation.

Mechanism of action

The antihistamine component works by blocking histamine H1 receptors, which helps alleviate allergy symptoms such as sneezing, itching, and runny nose. The decongestant acts on adrenergic receptors in the nasal mucosa, causing vasoconstriction and reducing nasal congestion. Analgesic components help relieve pain by inhibiting the synthesis of prostaglandins in the central nervous system.

Pharmacodynamics

The combination of antihistamine and decongestant provides a synergistic effect, offering relief from multiple symptoms associated with colds and allergies. The antihistamine reduces allergic reactions and their symptoms, while the decongestant improves airflow through the nasal passages. The analgesic component alleviates discomfort, enhancing the overall therapeutic effect of the drug.

Pharmacokinetics

Absorption rates can vary based on the specific formulations of the drug. Typically, antihistamines are well absorbed from the gastrointestinal tract, with peak plasma concentrations occurring within 1 to 3 hours. Decongestants may have variable bioavailability depending on the route of administration. Metabolism mainly occurs in the liver, and elimination half-lives can range from a few hours to several hours depending on the specific agents included. Renal excretion plays a significant role in the clearance of these drugs.

Pregnancy

Safety in pregnancy has not been established. Use only if clearly needed and the benefits outweigh the risks.

Breast-feeding

Data is limited; use caution and consider the potential risks versus benefits.

Storage

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

Mechanism of action

Dichloromethane induces mammary adenomas in rats through an indirect mechanism involving hyperprolactinaemia, resulting in benign neoplasms. It does not bind to DNA in various tissues, suggesting that its carcinogenic effects are likely mediated through metabolic pathways in the liver. In mice, DCM acts as a hepatic and pulmonary carcinogen, mediated by interaction with DNA through a glutathione (GSH) conjugate produced by the enzyme glutathione S-transferase T1-1 (GST T1-1).

Pharmacodynamics

Dichloromethane exhibits carcinogenic properties, particularly evident in animal studies where exposure leads to liver and lung tumors. The incidence of tumors varies by species, with higher susceptibility observed in mice due to differences in glutathione transferase activity. Its effects on humans are still uncertain, necessitating caution in its handling and use due to potential health risks.

Pharmacokinetics

Dichloromethane is rapidly absorbed through inhalation and dermal exposure, with peak blood concentrations occurring shortly after exposure. It undergoes extensive hepatic metabolism primarily via cytochrome P450 enzymes, leading to the formation of reactive metabolites. The elimination half-life is relatively short, with excretion occurring mainly through the lungs and urine.

Pregnancy

Dichloromethane should be avoided during pregnancy due to its potential carcinogenic effects and lack of safety data in pregnant women.

Breast-feeding

It is not known whether dichloromethane is excreted in human milk, thus it should be used with caution in breastfeeding mothers.

Storage

Store in a cool, dry place away from heat and light. Keep container tightly closed.

Indications

• Nausea
• Vomiting
• Chemotherapy-induced nausea
• Postoperative nausea
• Motion sickness

Dosage

Children: Refer to specific pediatric dosing guidelines for age-appropriate dosing.

Adults: Refer to specific guidelines for dosing based on the condition being treated, as doses can vary widely.

Mechanism of action

Drcoat acts as an antagonist to certain serotonin receptors, primarily 5-HT3 receptors, which are located in the central nervous system and the gastrointestinal tract. By blocking these receptors, Drcoat reduces the signaling associated with nausea and vomiting. This action helps to stabilize the gastrointestinal motility and decreases the likelihood of emesis during treatment protocols, particularly in patients undergoing chemotherapy or experiencing motion sickness.

Pharmacodynamics

The pharmacodynamics of Drcoat involve its interaction with the central and peripheral nervous systems. By inhibiting serotonin activity at the 5-HT3 receptor sites, Drcoat effectively dampens the excitatory signals that lead to nausea and vomiting. This results in a more stable gastrointestinal environment and improved patient comfort. The onset of action is generally rapid, with effects typically observed within one to two hours after administration.

Pharmacokinetics

Drcoat is absorbed well from the gastrointestinal tract, with peak plasma concentrations usually reached within one to three hours post-ingestion. The drug undergoes hepatic metabolism, primarily through cytochrome P450 enzymes, and is subsequently excreted through the urine, with a small proportion eliminated via feces. The half-life of the drug ranges from several hours to a day, depending on the specific formulation and individual patient factors.

Pregnancy

The safety of drcoat during pregnancy has not been established, and it should only be used if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

It is unknown if drcoat is excreted in human milk. Caution should be exercised when administering to nursing mothers.

Storage

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

Indications

• Antiseptic for skin disinfection
• Solvent in pharmaceutical formulations
• Cleaning agent in laboratories and healthcare settings

Dosage

Children: For pediatric use, consult specific guidelines in the BNF for Children, as dosing may vary based on age, weight, and clinical circumstances.

Adults: For skin antisepsis, apply isopropyl alcohol topically in a concentration of 70% to the affected area. Dosage may vary based on clinical indication and setting.

Mechanism of action

Isopropyl alcohol works primarily as an antiseptic by denaturing proteins and disrupting cell membranes of bacteria, viruses, and fungi, leading to cell lysis and death. Its efficacy is enhanced by the presence of water, which facilitates the penetration of the alcohol into microbial cells.

Pharmacodynamics

Isopropyl alcohol exhibits a rapid onset of action against a variety of pathogens, including gram-positive and gram-negative bacteria, fungi, and some viruses. Its antimicrobial activity is concentration-dependent, with higher concentrations generally providing a broader spectrum of activity. It is commonly used in concentrations ranging from 60% to 90%, with 70% being optimal for disinfection due to its ability to penetrate the cell wall effectively.

Pharmacokinetics

Isopropyl alcohol is readily absorbed through the skin and mucous membranes. After absorption, it is metabolized primarily in the liver to acetone, which is then further metabolized and excreted, mostly via urine. The elimination half-life of isopropyl alcohol varies but is typically around 2 to 3 hours. Its effects can be influenced by factors such as dosage, route of exposure, and individual metabolic differences.

Pregnancy

Isopropyl alcohol should be used with caution during pregnancy. It is a category C drug, indicating that risk cannot be ruled out.

Breast-feeding

Caution is advised when using isopropyl alcohol during breastfeeding, as it is not known if it is excreted in human milk.

Storage

Isopropyl alcohol should be stored at room temperature, away from heat and flame. Keep the container tightly closed and in a well-ventilated area.

Formulations

• Isopropyl alcohol 70% solution
• Isopropyl alcohol 99% solution

Indications

• Used as an excipient in tablet formulations
• Used as a bulking agent in capsule formulations
• Used in food products as a thickener or stabilizer

Dosage

Children: Refer to specific product guidelines as dosage will depend on the formulation and the active ingredients.

Adults: Refer to specific product guidelines as dosage will depend on the formulation and the active ingredients.

Mechanism of action

Microcrystalline cellulose acts as a non-digestible filler that enhances the flow properties of powders during the manufacturing of tablets and capsules. It does not have a direct pharmacological action on the body but ensures that the active ingredients are effectively delivered to the patient.

Pharmacodynamics

As a non-active ingredient, microcrystalline cellulose does not exert pharmacodynamic effects typical of active pharmaceutical ingredients. Its primary role is to provide a stable and consistent matrix for the drug, facilitating the release of the active compound once ingested.

Pharmacokinetics

Microcrystalline cellulose is not absorbed in the gastrointestinal tract; it passes through the digestive system largely unchanged. It adds bulk to the stool, which may aid in promoting regular bowel movements. The substance is excreted in feces, where it contributes to dietary fiber intake.

Pregnancy

Data regarding the use of microcrystalline cellulose during pregnancy is limited. It is advisable to consult with healthcare professionals before use.

Breast-feeding

Microcrystalline cellulose is considered safe during breastfeeding, as it is not absorbed systemically.

Storage

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

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

• Used as an excipient in drug formulations
• Pleurodesis for the management of recurrent pleural effusions

Dosage

Children: Refer to specific guidelines for paediatric use, as dosing may differ based on age and clinical condition.

Adults: Refer to specific guidelines for the appropriate dosage in pleurodesis and other applications, as it may vary based on clinical context.

Mechanism of action

Talc exhibits very good absorptive properties, allowing it to absorb moisture and other substances effectively. This characteristic is particularly useful in pharmaceutical formulations, where it may enhance the stability and texture of the drug product.

Pharmacodynamics

Talc's primary pharmacodynamic effect is its ability to act as an inert filler and bulking agent in pharmaceutical preparations. It does not have any intrinsic pharmacological activity but serves to improve the physical properties of formulations, such as flowability and compressibility.

Pharmacokinetics

Talc is not absorbed systemically when used as an excipient or in medical procedures. Its effects are local, and it remains in the site of application, where it functions primarily as a mechanical agent. The pharmacokinetics of talc in the context of its use in pleurodesis involves its ability to promote adhesion of the pleural surfaces, thereby preventing fluid accumulation.

Pregnancy

Talc is classified as a substance with minimal systemic absorption, but safety during pregnancy has not been well established. Consult relevant guidelines.

Breast-feeding

Talc is not expected to be absorbed in significant amounts; however, caution is advised and consult guidelines.

Storage

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

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

The bacterial cell wall, which is located at the periphery of Gram-positive bacteria and within the periplasm of Gram-negative bacteria, comprises a glycopeptide polymer synthesized through cross-linking of glycans to peptide stems on alternating saccharides, which is known commonly as peptidoglycan. Cell wall formation, recycling, and remodelling require numerous enzymes, including a family of enzymes with similar active site character despite distinct and sometimes overlapping roles as carboxypeptidases, endopeptidases, transpeptidases, and transglycosylases, known as "penicillin-binding proteins" (PBPs). The number of PBPs differs between bacteria, in which some are considered essential and others redundant. In general, inhibition of one or more essential PBPs results in impaired cell wall homeostasis, loss of cell integrity, and is ultimately bactericidal. Cefixime is a cephalosporin and cephalosporins work by using their beta-lactam rings to inhibit bacterial cell wall synthesis by binding to the penicillin-binding proteins transpeptidases on bacteria. The inhibition of synthesis of the bacteria cell wall will cause lysis, particularly in fast growing organisms such as bacteria. Specifically, cephalosporins inhibit penicillin-sensitive enzymes responsible for the final 3D structure of the bacterial cell wall which in turn inhibit bacterial cell wall peptidoglycan synthesis.

Pharmacodynamics

Cefixime, a broad-spectrum antibiotic, is an orally-active third-generation semisynthetic cephalosporin. Like other cephalosporins, the antibacterial action of cefixime results from inhibition of cell wall synthesis. Also like other cephalosporins, cefixime is stable when in the presence of certain beta-lactamase enzymes, which means certain organisms resistant to penicillins and some cephalosporins due to the presence of beta-lactamases could be susceptible to cefixime. Use of cefixime can result in hypersensitivity reactions including anaphylactic/anaphylactoid reactions and _Clostridium difficile_-associated diarrhea (CDAD); it may also be associated with a fall in prothrombin activity. Cefixime doses should be adjusted for patients that have renal impairment and patients undergoing continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD), while patients on dialysis should be monitored while taking cefixime.

Mechanism of action

The mechanism by which methylene chloride induces mammary adenomas in the rat is important for human hazard assessment. Female Sprague- Dawley rats receiving methylene chloride have a high blood level of prolactin. In common with the response to other agents which act via hyperprolactinaemia, the methylene chloride-induced response is of benign neoplasms only. There is no evidence for the binding of methylene chloride to the DNA of other tissues and hence it seems unlikely that it will bind to mammary tissue when the primary site of metabolism is the liver. It seems most likely, therefore, that the increased incidence of mammary adenomas is the result of an indirect mechanism operating via hyperprolactinaemia. Dichloromethane (DCM) is a hepatic and pulmonary carcinogen in mice exposed to high doses by inhalation. It has been shown previously that the incidence of liver and lung tumors does not increase in rats or hamsters exposed to the dihaloalkane under conditions similar to those that produced tumors in mice. The biological consequences of DCM exposure to humans is therefore uncertain. The carcinogenic effects of DCM in the mouse are caused by the interaction with DNA of a glutathione (GSH) conjugate that is produced by the class theta glutathione S-transferase T1-1 (GST T1-1). The species specificity is thought to be due to the greater amount of transferase activity in mouse target organs and specific nuclear localization of GST T1-1 in target cells. This paper directly compares the relative capacity and locality of DCM activation in mouse and human tissues. The results show that mouse GST T1-1 is more efficient in catalyzing the conjugation of DCM with GSH than the orthologous human enzyme. In addition, the mouse expresses higher levels of the transferase than humans in hepatic tissue. Histochemical analysis confirmed the presence of GST T1-1 in the nucleus of mouse liver cells. However, in human liver GST T1-1 was detected in bile duct epithelial cells and hepatocyte nuclei but was also present in the cytoplasm. Taking this information into account, it is unlikely that humans have a sufficiently high capacity to activate DCM for this compound to be considered to represent a carcinogenic risk. Dichloromethane (DCM) is considered a probable human carcinogen. Laboratory studies have shown an increased incidence of lung and liver cancer in mice but not in rats or hamsters. Despite the correlation between metabolism of DCM by the glutathione-S-transferase (GST) pathway and the occurrence of tumors in different species, the mechanism of tumor induction by DCM metabolites produced through the GST pathway remains unclear. In this study a V79 cell line stably transfected with the murine GST theta 1 gene (mGSTT1) was compared to the parent cell line (MZ) to determine how the construct affects DCM metabolism and the sensitivity of the cell line to DNA damage and cytotoxicity. V79 cells were treated with DCM (2.5-10mM) or formaldehyde (150-600muM) for 2hr. Also, formaldehyde produced by V79 cytosol metabolism of DCM was measured spectrophotometrically. DNA damage and DNA-protein crosslinks were measured by the standard and proteinase K-modified alkaline single cell gel electrophoresis (SCG) assays. Cytotoxicity was assessed by trypan blue stain exclusion, the Live/Dead((R)) cell viability/cytotoxicity kit for animal cells, and the neutral red assay. After DCM treatment a significant concentration-dependent increase in tail moment in the V79 MZ cells was observed compared to a significant concentration-dependent decrease in tail moment in the V79 mGSTT1 cells. Post-incubation with proteinase K significantly increased DNA migrations in DCM-treated V79 mGSTT1 cells. DCM formed significantly higher levels of formaldehyde in the cytosol of the V79 mGSTT1 cells than in the cytosol of the V79 MZ cells. Results using the cytotoxicity assays were comparable using the trypan blue and Live/Dead((R)) assays, neither showing a difference in resp

Mechanism of action

It has very good absorptive properties.