BAYTRIL OTIC

Indications

• Bacterial infections
• Respiratory tract infections
• Urinary tract infections
• Skin infections
• Gastrointestinal infections

Dosage

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

Adults: Refer to the specific product guidelines for dosing information, as it can vary based on the indication and formulation used.

Mechanism of action

Enrofloxacin exerts its antibacterial effect through the inhibition of bacterial DNA gyrase and topoisomerase IV, which are essential enzymes for DNA replication and transcription. By interfering with these enzymes, enrofloxacin disrupts the normal function of the bacterial cell, leading to cell death.

Pharmacodynamics

Enrofloxacin has a bactericidal effect, meaning it kills bacteria rather than merely inhibiting their growth. Its activity is concentration-dependent, meaning that higher concentrations lead to more significant antibacterial effects. The drug has a broad spectrum of activity against many gram-negative bacteria, including Pseudomonas aeruginosa, as well as some gram-positive organisms.

Pharmacokinetics

Enrofloxacin is well-absorbed after oral administration, with peak plasma concentrations typically achieved within 1 to 2 hours. It is widely distributed throughout the body, including into tissues and fluids, and has good penetration into the central nervous system. The elimination half-life varies but is generally between 4 to 8 hours in humans. Enrofloxacin is primarily metabolized in the liver, and its metabolites, including ciprofloxacin, are also active against bacteria.

Contra-indications

• Hypersensitivity to enrofloxacin or any of its components
• Use in growing animals due to potential effects on cartilage development

Adverse effects

• Gastrointestinal disturbances such as vomiting and diarrhea
• Central nervous system effects including seizures and ataxia
• Tendon rupture or damage, particularly in larger breed dogs
• Possible cartilage damage in young animals

Interactions

• Antacids or products containing aluminum, magnesium, or iron may reduce the absorption of enrofloxacin
• Cationic agents may interfere with its antimicrobial activity
• Concurrent use with other nephrotoxic drugs may increase the risk of renal toxicity

Precautions

• Use with caution in animals with a history of seizures or renal impairment
• Monitor for signs of adverse reactions during therapy
• Not for use in animals with known hypersensitivity to fluoroquinolones

Pregnancy

Safety during pregnancy has not been established, use only if benefits outweigh risks.

Breast-feeding

Safety during lactation has not been fully established, use with caution.

Storage

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

Formulations

• Injectable solution
• Oral tablets
• Oral suspension

Indications

• Management of wounds
• Burn treatment
• Dental caries prevention
• Topical antiseptic
• Infection control in medical devices

Dosage

Children: Refer to BNF for Children for age-appropriate dosing recommendations.

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

Mechanism of action

Silver ions precipitate with chloride or phosphate anions and bind to proteins, leading to antibacterial effects by disrupting cell membranes. They can bind to peptidoglycans in bacterial cell walls, causing loss of structural integrity and function. Silver also binds to and oxidizes sulphydryl groups in enzymes, inhibiting metabolic processes. Additionally, silver ions may attach to bacterial DNA, inhibiting replication, and silver nanoparticles can generate reactive oxygen species, causing oxidative stress.

Pharmacodynamics

Silver exhibits broad-spectrum antimicrobial activity, effective against both Gram-positive and Gram-negative bacteria, including _Streptococcus mutans_, _Staphylococcus aureus_, and _Escherichia coli_. It has shown dose-dependent effects against methicillin-resistant Staphylococcus aureus (MRSA). Furthermore, silver compounds have demonstrated anti-inflammatory properties in models of skin inflammation and ulcerative colitis, suppressing pro-inflammatory cytokines and matrix metalloproteinases.

Pharmacokinetics

Silver does not have a well-defined pharmacokinetic profile due to its nature as a metal; however, it is known to bind extensively to proteins and tissues. Chronic exposure to silver can lead to accumulation and potential toxicity. The absorption and distribution of silver ions can vary based on the form of silver administered, with nanoparticles showing different properties compared to ionic silver.

Pregnancy

Safety during pregnancy has not been established. Use only if clearly needed.

Breast-feeding

Caution is advised as it is not known whether silver is excreted in human milk.

Storage

Store in a well-closed container, protected from light, at room temperature.

Formulations

• Silver nitrate
• Nanocrystalline silver

Indications

• Urinary tract infections
• Respiratory infections
• Gastrointestinal infections
• Skin and soft tissue infections

Dosage

Children: Refer to the BNF for Children for appropriate pediatric dosing guidelines based on age and weight.

Adults: Refer to the specific prescribing information or guidelines for appropriate dosing based on the condition being treated and patient factors.

Mechanism of action

Sulfacliazinc acts as a competitive inhibitor of the bacterial enzyme dihydropteroate synthase, which is crucial for the synthesis of folate. By blocking this enzyme, sulfacliazinc prevents the conversion of para-aminobenzoic acid (PABA) to dihydropteroic acid, a precursor of folic acid. This disruption leads to a depletion of folate levels in bacteria, ultimately inhibiting their growth and replication.

Pharmacodynamics

The pharmacodynamics of sulfacliazinc involves its bacteriostatic action against a wide range of Gram-positive and Gram-negative bacteria. The drug's efficacy is influenced by the local concentration at the site of infection and the susceptibility of the bacterial strain. Sulfacliazinc demonstrates time-dependent killing, meaning that the duration of exposure to the drug is critical for its antibacterial effect. Resistance mechanisms can include alterations in the target enzyme and increased production of PABA.

Pharmacokinetics

Sulfacliazinc is absorbed from the gastrointestinal tract, with peak plasma concentrations typically achieved within a few hours post-administration. The drug is widely distributed throughout body tissues and fluids, including the lungs, liver, and kidneys. Sulfacliazinc is metabolized in the liver and excreted primarily via the kidneys. Its half-life can vary depending on renal function, and dosage adjustments may be necessary in patients with impaired renal clearance.

Contra-indications

• Hypersensitivity to sulfonamides
• Severe renal impairment
• Porphyria

Adverse effects

• Rash
• Nausea
• Vomiting
• Agranulocytosis
• Stevens-Johnson syndrome
• Hepatic necrosis
• Cystalluria

Interactions

• May enhance the effects of anticoagulants
• May displace bilirubin from albumin in newborns
• Potential interaction with methotrexate leading to increased toxicity

Precautions

• Use with caution in patients with renal or hepatic impairment
• Monitor blood counts regularly due to the risk of bone marrow suppression
• Avoid in patients with G6PD deficiency

Pregnancy

Sulfacliazinc is generally not recommended during pregnancy due to potential risks to the fetus, including kernicterus.

Breast-feeding

Sulfacliazinc is excreted in breast milk, and caution is advised when administered to nursing mothers.

Storage

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

Formulations

• Tablets
• Oral suspension

Mechanism of action

To elucidate the possible mechanism of initiation of lipid peroxidation in silver nitrate treated erythrocytes, the effect of AgNO3 on Hb catalyzed peroxidation of phospholipid liposomes was studied. Ag+ significantly increases the rate of Hb-catalyzed peroxidation. The inhibition of this effect by superoxide dismutase and catalase suggests that superoxide radical and H2O2 are involved. It was demonstrated also that Ag+ potentiates the Hb autoxidation and increases the binding of Hb to the erythrocyte membrane. Silver nitrate exhibits antiseptic, germicidal, astringent, and caustic or escharotic activity. These effects may result from silver ions readily combining with sulfhydryl, carboxyl, phosphate, amino, and other biologically important chemical groups. When silver ions interact with proteins, physical properties of the protein are usually altered; the protein may be denatured and precipitation usually occurs. Silver ions act on the surface of bacteria causing substantial changes in the cell wall and membrane. The germicidal activity of silver nitrate may be attributed to precipitation of bacterial proteins by liberated silver ions.

Mechanism of action

The majority of released silver ions precipitate with chloride or phosphate anions or bind to albumins, macroglobulins, or tissue debris. While bound silver ions do not exert antibacterial actions, they may potentially play a role in silver toxicity in case of chronic exposure. Silver ions mediate antibacterial effects via disrupting the bacterial, fungal, and protozoal cell membranes; they bind to disulphide in membrane proteins, readily allowing penetration through the membranes and intracellular absorption via pinocytosis. They may also bind to negatively-charged peptidoglycans in the cell wall via electrostatic interactions, leading to disruption of membrane transport function and loss of structural integrity. Silver ions also bind to and oxidize sulphydryl groups (SH) in bacterial cytoplasmic enzymes to aberrate their function in metabolic processes. Silver nanoparticles may cause an increase in reactive oxygen species (ROS) inside the microbial cells leading to metal-induced oxidative stress and cell damage. They also modulate cellular signal system via inhibition of phosphorylation of essential bacterial proteins to eventually cause cell death. It is also reported that silver ions also attach to guanine in bacterial DNA, which inhibits DNA replication. While it is not fully understood, the mode of action of silver compounds in preventing and arresting dental caries is thought to involve inhibition of the demineralization process in addition to cytoplasmic and membrane function perturbation mentioned above. Silver compounds may directly interact with hydroxyapatite, a major tooth component. Light catalyzes the reduction of silver salts deposited in skin to metallic silver & it /is/ subsequently oxidized to silver sulfide; it is the deposition of the latter compound which accounts for the gray discoloration pathognomonic of argyria. /Silver and compounds/ Silver nanoparticles (nano-Ag) are potent and broad-spectrum antimicrobial agents. In this study, spherical nano-Ag (average diameter = 9.3 nm) particles were synthesized using a borohydride reduction method and the mode of their antibacterial action against E. coli was investigated by proteomic approaches (2-DE and MS identification), conducted in parallel to analyses involving solutions of Ag(+) ions. The proteomic data revealed that a short exposure of E. coli cells to antibacterial concentrations of nano-Ag resulted in an accumulation of envelope protein precursors, indicative of the dissipation of proton motive force. Consistent with these proteomic findings, nano-Ag were shown to destabilize the outer membrane, collapse the plasma membrane potential and deplete the levels of intracellular ATP. The mode of action of nano-Ag was also found to be similar to that of Ag(+) ions ... however, the effective concentrations of nano-Ag and Ag(+) ions were at nanomolar and micromolar levels, respectively. Nano-Ag appear to be an efficient physicochemical system conferring antimicrobial silver activities.

Pharmacodynamics

Silver exhibits a broad-spectrum antimicrobial activity. Silver ions were shown to mediate an effective antibacterial action against _Streptococcus mutans_, one of major bacteria present in the human oral cavity and one of etiological microorganism of dental caries. A study reported a dose-dependent antimicrobial activity of silver nanoparticles against MRSA and non-MRSA bacteria. Silver nanoparticles were also shown to mediate antibacterial activity against Gram-positive _S. aureus_ and Gram-negative _E. coli_ by inhibiting the growth. In experimental dinitrochlorobenzene-induced inflammatory models in porcine or murine skin, topical application of silver nitrate and nanocrystalline silver were shown to exert anti-inflammatory effects associated with lymphocyte apoptosis, decreased expression of pro-inflammatory cytokines, and reduced gelatinase activity. In a rat model of ulcerative colitis, orally or intracolonically administered nanocrystalline silver were shown to suppress matrix metalloproteinase (MMP-9), tumour necrosis factor (TNF), and interleukin-β (IL-β) and IL-12.